Rename Node to PtNodeArray

Bug: 10247660
Change-Id: I1a0ac19f58f96adb5efac5fd35c6404831618c99

19 files changed, 401 insertions, 380 deletions

diff --git a/java/src/com/android/inputmethod/latin/DictionaryWriter.java b/java/src/com/android/inputmethod/latin/DictionaryWriter.java
index 3b300a3fd..1765ce5f8 100644
--- a/java/src/com/android/inputmethod/latin/DictionaryWriter.java
+++ b/java/src/com/android/inputmethod/latin/DictionaryWriter.java
@@ -23,7 +23,7 @@ import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
 import com.android.inputmethod.latin.makedict.BinaryDictEncoder;
 import com.android.inputmethod.latin.makedict.FormatSpec;
 import com.android.inputmethod.latin.makedict.FusionDictionary;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.makedict.UnsupportedFormatException;
 import com.android.inputmethod.latin.utils.CollectionUtils;
@@ -51,7 +51,7 @@ public class DictionaryWriter extends AbstractDictionaryWriter {
     @Override
     public void clear() {
         final HashMap<String, String> attributes = CollectionUtils.newHashMap();
-        mFusionDictionary = new FusionDictionary(new Node(),
+        mFusionDictionary = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(attributes, false, false));
     }
 
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoder.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoder.java
index 767f4fc72..01cc8ac1e 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoder.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoder.java
@@ -20,7 +20,7 @@ import com.android.inputmethod.annotations.UsedForTesting;
 import com.android.inputmethod.latin.makedict.FormatSpec.FileHeader;
 import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
 import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.utils.JniUtils;
 
@@ -548,31 +548,31 @@ public final class BinaryDictDecoder {
     }
 
     /**
-     * Reads a single node from a buffer.
+     * Reads a single node array from a buffer.
      *
-     * This methods reads the file at the current position. A node is fully expected to start at
-     * the current position.
-     * This will recursively read other nodes into the structure, populating the reverse
+     * This methods reads the file at the current position. A node array is fully expected to start
+     * at the current position.
+     * This will recursively read other node arrays into the structure, populating the reverse
      * maps on the fly and using them to keep track of already read nodes.
      *
-     * @param buffer the buffer, correctly positioned at the start of a node.
+     * @param buffer the buffer, correctly positioned at the start of a node array.
      * @param headerSize the size, in bytes, of the file header.
-     * @param reverseNodeMap a mapping from addresses to already read nodes.
+     * @param reverseNodeArrayMap a mapping from addresses to already read node arrays.
      * @param reverseGroupMap a mapping from addresses to already read character groups.
      * @param options file format options.
-     * @return the read node with all his children already read.
+     * @return the read node array with all his children already read.
      */
-    private static Node readNode(final FusionDictionaryBufferInterface buffer, final int headerSize,
-            final Map<Integer, Node> reverseNodeMap, final Map<Integer, CharGroup> reverseGroupMap,
-            final FormatOptions options)
+    private static PtNodeArray readNodeArray(final FusionDictionaryBufferInterface buffer,
+            final int headerSize, final Map<Integer, PtNodeArray> reverseNodeArrayMap,
+            final Map<Integer, CharGroup> reverseGroupMap, final FormatOptions options)
             throws IOException {
-        final ArrayList<CharGroup> nodeContents = new ArrayList<CharGroup>();
-        final int nodeOrigin = buffer.position() - headerSize;
+        final ArrayList<CharGroup> nodeArrayContents = new ArrayList<CharGroup>();
+        final int nodeArrayOrigin = buffer.position() - headerSize;
 
         do { // Scan the linked-list node.
-            final int nodeHeadPosition = buffer.position() - headerSize;
+            final int nodeArrayHeadPosition = buffer.position() - headerSize;
             final int count = readCharGroupCount(buffer);
-            int groupOffset = nodeHeadPosition + BinaryDictIOUtils.getGroupCountSize(count);
+            int groupOffset = nodeArrayHeadPosition + BinaryDictIOUtils.getGroupCountSize(count);
             for (int i = count; i > 0; --i) { // Scan the array of CharGroup.
                 CharGroupInfo info = readCharGroup(buffer, groupOffset, options);
                 if (BinaryDictIOUtils.isMovedGroup(info.mFlags, options)) continue;
@@ -589,21 +589,21 @@ public final class BinaryDictDecoder {
                     }
                 }
                 if (BinaryDictIOUtils.hasChildrenAddress(info.mChildrenAddress)) {
-                    Node children = reverseNodeMap.get(info.mChildrenAddress);
+                    PtNodeArray children = reverseNodeArrayMap.get(info.mChildrenAddress);
                     if (null == children) {
                         final int currentPosition = buffer.position();
                         buffer.position(info.mChildrenAddress + headerSize);
-                        children = readNode(
-                                buffer, headerSize, reverseNodeMap, reverseGroupMap, options);
+                        children = readNodeArray(
+                                buffer, headerSize, reverseNodeArrayMap, reverseGroupMap, options);
                         buffer.position(currentPosition);
                     }
-                    nodeContents.add(
+                    nodeArrayContents.add(
                             new CharGroup(info.mCharacters, shortcutTargets, bigrams,
                                     info.mFrequency,
                                     0 != (info.mFlags & FormatSpec.FLAG_IS_NOT_A_WORD),
                                     0 != (info.mFlags & FormatSpec.FLAG_IS_BLACKLISTED), children));
                 } else {
-                    nodeContents.add(
+                    nodeArrayContents.add(
                             new CharGroup(info.mCharacters, shortcutTargets, bigrams,
                                     info.mFrequency,
                                     0 != (info.mFlags & FormatSpec.FLAG_IS_NOT_A_WORD),
@@ -624,11 +624,11 @@ public final class BinaryDictDecoder {
         } while (options.mSupportsDynamicUpdate &&
                 buffer.position() != FormatSpec.NO_FORWARD_LINK_ADDRESS);
 
-        final Node node = new Node(nodeContents);
-        node.mCachedAddressBeforeUpdate = nodeOrigin;
-        node.mCachedAddressAfterUpdate = nodeOrigin;
-        reverseNodeMap.put(node.mCachedAddressAfterUpdate, node);
-        return node;
+        final PtNodeArray nodeArray = new PtNodeArray(nodeArrayContents);
+        nodeArray.mCachedAddressBeforeUpdate = nodeArrayOrigin;
+        nodeArray.mCachedAddressAfterUpdate = nodeArrayOrigin;
+        reverseNodeArrayMap.put(nodeArray.mCachedAddressAfterUpdate, nodeArray);
+        return nodeArray;
     }
 
     /**
@@ -733,10 +733,10 @@ public final class BinaryDictDecoder {
         // Read header
         final FileHeader header = readHeader(reader.getBuffer());
 
-        Map<Integer, Node> reverseNodeMapping = new TreeMap<Integer, Node>();
+        Map<Integer, PtNodeArray> reverseNodeArrayMapping = new TreeMap<Integer, PtNodeArray>();
         Map<Integer, CharGroup> reverseGroupMapping = new TreeMap<Integer, CharGroup>();
-        final Node root = readNode(reader.getBuffer(), header.mHeaderSize, reverseNodeMapping,
-                reverseGroupMapping, header.mFormatOptions);
+        final PtNodeArray root = readNodeArray(reader.getBuffer(), header.mHeaderSize,
+                reverseNodeArrayMapping, reverseGroupMapping, header.mFormatOptions);
 
         FusionDictionary newDict = new FusionDictionary(root, header.mDictionaryOptions);
         if (null != dict) {
@@ -803,8 +803,6 @@ public final class BinaryDictDecoder {
     /**
      * Calculate bigram frequency from compressed value
      *
-     * @see #makeBigramFlags
-     *
      * @param unigramFrequency
      * @param bigramFrequency compressed frequency
      * @return approximate bigram frequency
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictEncoder.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictEncoder.java
index 85219e485..d9005b926 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictEncoder.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictEncoder.java
@@ -20,7 +20,7 @@ import com.android.inputmethod.latin.makedict.BinaryDictDecoder.CharEncoding;
 import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
 import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
 import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 
 import java.io.ByteArrayOutputStream;
@@ -78,12 +78,12 @@ public class BinaryDictEncoder {
     }
 
     /**
-     * Compute the binary size of the group count for a node
-     * @param node the node
+     * Compute the binary size of the group count for a node array.
+     * @param nodeArray the nodeArray
      * @return the size of the group count, either 1 or 2 bytes.
      */
-    private static int getGroupCountSize(final Node node) {
-        return BinaryDictIOUtils.getGroupCountSize(node.mData.size());
+    private static int getGroupCountSize(final PtNodeArray nodeArray) {
+        return BinaryDictIOUtils.getGroupCountSize(nodeArray.mData.size());
     }
 
     /**
@@ -138,15 +138,17 @@ public class BinaryDictEncoder {
     }
 
     /**
-     * Compute the maximum size of a node, assuming 3-byte addresses for everything, and caches
-     * it in the 'actualSize' member of the node.
+     * Compute the maximum size of each node of a node array, assuming 3-byte addresses for
+     * everything, and caches it in the `mCachedSize' member of the nodes; deduce the size of
+     * the containing node array, and cache it it its 'mCachedSize' member.
      *
-     * @param node the node to compute the maximum size of.
+     * @param nodeArray the node array to compute the maximum size of.
      * @param options file format options.
      */
-    private static void calculateNodeMaximumSize(final Node node, final FormatOptions options) {
-        int size = getGroupCountSize(node);
-        for (CharGroup g : node.mData) {
+    private static void calculateNodeArrayMaximumSize(final PtNodeArray nodeArray,
+            final FormatOptions options) {
+        int size = getGroupCountSize(nodeArray);
+        for (CharGroup g : nodeArray.mData) {
             final int groupSize = getCharGroupMaximumSize(g, options);
             g.mCachedSize = groupSize;
             size += groupSize;
@@ -154,7 +156,7 @@ public class BinaryDictEncoder {
         if (options.mSupportsDynamicUpdate) {
             size += FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
         }
-        node.mCachedSize = size;
+        nodeArray.mCachedSize = size;
     }
 
     /**
@@ -199,14 +201,16 @@ public class BinaryDictEncoder {
 
     // This method is responsible for finding a nice ordering of the nodes that favors run-time
     // cache performance and dictionary size.
-    /* package for tests */ static ArrayList<Node> flattenTree(final Node root) {
-        final int treeSize = FusionDictionary.countCharGroups(root);
+    /* package for tests */ static ArrayList<PtNodeArray> flattenTree(
+            final PtNodeArray rootNodeArray) {
+        final int treeSize = FusionDictionary.countCharGroups(rootNodeArray);
         MakedictLog.i("Counted nodes : " + treeSize);
-        final ArrayList<Node> flatTree = new ArrayList<Node>(treeSize);
-        return flattenTreeInner(flatTree, root);
+        final ArrayList<PtNodeArray> flatTree = new ArrayList<PtNodeArray>(treeSize);
+        return flattenTreeInner(flatTree, rootNodeArray);
     }
 
-    private static ArrayList<Node> flattenTreeInner(final ArrayList<Node> list, final Node node) {
+    private static ArrayList<PtNodeArray> flattenTreeInner(final ArrayList<PtNodeArray> list,
+            final PtNodeArray nodeArray) {
         // Removing the node is necessary if the tails are merged, because we would then
         // add the same node several times when we only want it once. A number of places in
         // the code also depends on any node being only once in the list.
@@ -224,8 +228,8 @@ public class BinaryDictEncoder {
         // this simple list.remove operation O(n*n) overall. On Android this overhead is very
         // high.
         // For future reference, the code to remove duplicate is a simple : list.remove(node);
-        list.add(node);
-        final ArrayList<CharGroup> branches = node.mData;
+        list.add(nodeArray);
+        final ArrayList<CharGroup> branches = nodeArray.mData;
         final int nodeSize = branches.size();
         for (CharGroup group : branches) {
             if (null != group.mChildren) flattenTreeInner(list, group.mChildren);
@@ -234,52 +238,60 @@ public class BinaryDictEncoder {
     }
 
     /**
-     * Get the offset from a position inside a current node to a target node, during update.
-     *
-     * If the current node is before the target node, the target node has not been updated yet,
-     * so we should return the offset from the old position of the current node to the old position
-     * of the target node. If on the other hand the target is before the current node, it already
-     * has been updated, so we should return the offset from the new position in the current node
-     * to the new position in the target node.
-     * @param currentNode the node containing the CharGroup where the offset will be written
-     * @param offsetFromStartOfCurrentNode the offset, in bytes, from the start of currentNode
-     * @param targetNode the target node to get the offset to
-     * @return the offset to the target node
+     * Get the offset from a position inside a current node array to a target node array, during
+     * update.
+     *
+     * If the current node array is before the target node array, the target node array has not
+     * been updated yet, so we should return the offset from the old position of the current node
+     * array to the old position of the target node array. If on the other hand the target is
+     * before the current node array, it already has been updated, so we should return the offset
+     * from the new position in the current node array to the new position in the target node
+     * array.
+     *
+     * @param currentNodeArray node array containing the CharGroup where the offset will be written
+     * @param offsetFromStartOfCurrentNodeArray offset, in bytes, from the start of currentNodeArray
+     * @param targetNodeArray the target node array to get the offset to
+     * @return the offset to the target node array
      */
-    private static int getOffsetToTargetNodeDuringUpdate(final Node currentNode,
-            final int offsetFromStartOfCurrentNode, final Node targetNode) {
-        final boolean isTargetBeforeCurrent = (targetNode.mCachedAddressBeforeUpdate
-                < currentNode.mCachedAddressBeforeUpdate);
+    private static int getOffsetToTargetNodeArrayDuringUpdate(final PtNodeArray currentNodeArray,
+            final int offsetFromStartOfCurrentNodeArray, final PtNodeArray targetNodeArray) {
+        final boolean isTargetBeforeCurrent = (targetNodeArray.mCachedAddressBeforeUpdate
+                < currentNodeArray.mCachedAddressBeforeUpdate);
         if (isTargetBeforeCurrent) {
-            return targetNode.mCachedAddressAfterUpdate
-                    - (currentNode.mCachedAddressAfterUpdate + offsetFromStartOfCurrentNode);
+            return targetNodeArray.mCachedAddressAfterUpdate
+                    - (currentNodeArray.mCachedAddressAfterUpdate
+                            + offsetFromStartOfCurrentNodeArray);
         } else {
-            return targetNode.mCachedAddressBeforeUpdate
-                    - (currentNode.mCachedAddressBeforeUpdate + offsetFromStartOfCurrentNode);
+            return targetNodeArray.mCachedAddressBeforeUpdate
+                    - (currentNodeArray.mCachedAddressBeforeUpdate
+                            + offsetFromStartOfCurrentNodeArray);
         }
     }
 
     /**
-     * Get the offset from a position inside a current node to a target CharGroup, during update.
-     * @param currentNode the node containing the CharGroup where the offset will be written
-     * @param offsetFromStartOfCurrentNode the offset, in bytes, from the start of currentNode
+     * Get the offset from a position inside a current node array to a target CharGroup, during
+     * update.
+     *
+     * @param currentNodeArray node array containing the CharGroup where the offset will be written
+     * @param offsetFromStartOfCurrentNodeArray offset, in bytes, from the start of currentNodeArray
      * @param targetCharGroup the target CharGroup to get the offset to
      * @return the offset to the target CharGroup
      */
     // TODO: is there any way to factorize this method with the one above?
-    private static int getOffsetToTargetCharGroupDuringUpdate(final Node currentNode,
-            final int offsetFromStartOfCurrentNode, final CharGroup targetCharGroup) {
-        final int oldOffsetBasePoint = currentNode.mCachedAddressBeforeUpdate
-                + offsetFromStartOfCurrentNode;
+    private static int getOffsetToTargetCharGroupDuringUpdate(final PtNodeArray currentNodeArray,
+            final int offsetFromStartOfCurrentNodeArray, final CharGroup targetCharGroup) {
+        final int oldOffsetBasePoint = currentNodeArray.mCachedAddressBeforeUpdate
+                + offsetFromStartOfCurrentNodeArray;
         final boolean isTargetBeforeCurrent = (targetCharGroup.mCachedAddressBeforeUpdate
                 < oldOffsetBasePoint);
-        // If the target is before the current node, then its address has already been updated.
-        // We can use the AfterUpdate member, and compare it to our own member after update.
-        // Otherwise, the AfterUpdate member is not updated yet, so we need to use the BeforeUpdate
-        // member, and of course we have to compare this to our own address before update.
+        // If the target is before the current node array, then its address has already been
+        // updated. We can use the AfterUpdate member, and compare it to our own member after
+        // update. Otherwise, the AfterUpdate member is not updated yet, so we need to use the
+        // BeforeUpdate member, and of course we have to compare this to our own address before
+        // update.
         if (isTargetBeforeCurrent) {
-            final int newOffsetBasePoint = currentNode.mCachedAddressAfterUpdate
-                    + offsetFromStartOfCurrentNode;
+            final int newOffsetBasePoint = currentNodeArray.mCachedAddressAfterUpdate
+                    + offsetFromStartOfCurrentNodeArray;
             return targetCharGroup.mCachedAddressAfterUpdate - newOffsetBasePoint;
         } else {
             return targetCharGroup.mCachedAddressBeforeUpdate - oldOffsetBasePoint;
@@ -287,26 +299,26 @@ public class BinaryDictEncoder {
     }
 
     /**
-     * Computes the actual node size, based on the cached addresses of the children nodes.
+     * Computes the actual node array size, based on the cached addresses of the children nodes.
      *
-     * Each node stores its tentative address. During dictionary address computing, these
-     * are not final, but they can be used to compute the node size (the node size depends
-     * on the address of the children because the number of bytes necessary to store an
-     * address depends on its numeric value. The return value indicates whether the node
+     * Each node array stores its tentative address. During dictionary address computing, these
+     * are not final, but they can be used to compute the node array size (the node array size
+     * depends on the address of the children because the number of bytes necessary to store an
+     * address depends on its numeric value. The return value indicates whether the node array
      * contents (as in, any of the addresses stored in the cache fields) have changed with
      * respect to their previous value.
      *
-     * @param node the node to compute the size of.
+     * @param nodeArray the node array to compute the size of.
      * @param dict the dictionary in which the word/attributes are to be found.
      * @param formatOptions file format options.
-     * @return false if none of the cached addresses inside the node changed, true otherwise.
+     * @return false if none of the cached addresses inside the node array changed, true otherwise.
      */
-    private static boolean computeActualNodeSize(final Node node, final FusionDictionary dict,
-            final FormatOptions formatOptions) {
+    private static boolean computeActualNodeArraySize(final PtNodeArray nodeArray,
+            final FusionDictionary dict, final FormatOptions formatOptions) {
         boolean changed = false;
-        int size = getGroupCountSize(node);
-        for (CharGroup group : node.mData) {
-            group.mCachedAddressAfterUpdate = node.mCachedAddressAfterUpdate + size;
+        int size = getGroupCountSize(nodeArray);
+        for (CharGroup group : nodeArray.mData) {
+            group.mCachedAddressAfterUpdate = nodeArray.mCachedAddressAfterUpdate + size;
             if (group.mCachedAddressAfterUpdate != group.mCachedAddressBeforeUpdate) {
                 changed = true;
             }
@@ -318,16 +330,16 @@ public class BinaryDictEncoder {
                 if (formatOptions.mSupportsDynamicUpdate) {
                     groupSize += FormatSpec.SIGNED_CHILDREN_ADDRESS_SIZE;
                 } else {
-                    groupSize += getByteSize(getOffsetToTargetNodeDuringUpdate(node,
+                    groupSize += getByteSize(getOffsetToTargetNodeArrayDuringUpdate(nodeArray,
                             groupSize + size, group.mChildren));
                 }
             }
             groupSize += getShortcutListSize(group.mShortcutTargets);
             if (null != group.mBigrams) {
                 for (WeightedString bigram : group.mBigrams) {
-                    final int offset = getOffsetToTargetCharGroupDuringUpdate(node,
+                    final int offset = getOffsetToTargetCharGroupDuringUpdate(nodeArray,
                             groupSize + size + FormatSpec.GROUP_FLAGS_SIZE,
-                            FusionDictionary.findWordInTree(dict.mRoot, bigram.mWord));
+                            FusionDictionary.findWordInTree(dict.mRootNodeArray, bigram.mWord));
                     groupSize += getByteSize(offset) + FormatSpec.GROUP_FLAGS_SIZE;
                 }
             }
@@ -337,49 +349,49 @@ public class BinaryDictEncoder {
         if (formatOptions.mSupportsDynamicUpdate) {
             size += FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
         }
-        if (node.mCachedSize != size) {
-            node.mCachedSize = size;
+        if (nodeArray.mCachedSize != size) {
+            nodeArray.mCachedSize = size;
             changed = true;
         }
         return changed;
     }
 
     /**
-     * Initializes the cached addresses of nodes from their size.
+     * Initializes the cached addresses of node arrays and their containing nodes from their size.
      *
-     * @param flatNodes the array of nodes.
+     * @param flatNodes the list of node arrays.
      * @param formatOptions file format options.
      * @return the byte size of the entire stack.
      */
-    private static int initializeNodesCachedAddresses(final ArrayList<Node> flatNodes,
+    private static int initializeNodeArraysCachedAddresses(final ArrayList<PtNodeArray> flatNodes,
             final FormatOptions formatOptions) {
-        int nodeOffset = 0;
-        for (final Node n : flatNodes) {
-            n.mCachedAddressBeforeUpdate = nodeOffset;
-            int groupCountSize = getGroupCountSize(n);
+        int nodeArrayOffset = 0;
+        for (final PtNodeArray nodeArray : flatNodes) {
+            nodeArray.mCachedAddressBeforeUpdate = nodeArrayOffset;
+            int groupCountSize = getGroupCountSize(nodeArray);
             int groupOffset = 0;
-            for (final CharGroup g : n.mData) {
+            for (final CharGroup g : nodeArray.mData) {
                 g.mCachedAddressBeforeUpdate = g.mCachedAddressAfterUpdate =
-                        groupCountSize + nodeOffset + groupOffset;
+                        groupCountSize + nodeArrayOffset + groupOffset;
                 groupOffset += g.mCachedSize;
             }
             final int nodeSize = groupCountSize + groupOffset
                     + (formatOptions.mSupportsDynamicUpdate
                             ? FormatSpec.FORWARD_LINK_ADDRESS_SIZE : 0);
-            nodeOffset += n.mCachedSize;
+            nodeArrayOffset += nodeArray.mCachedSize;
         }
-        return nodeOffset;
+        return nodeArrayOffset;
     }
 
     /**
-     * Updates the cached addresses of nodes after recomputing their new positions.
+     * Updates the cached addresses of node arrays after recomputing their new positions.
      *
-     * @param flatNodes the array of nodes.
+     * @param flatNodes the list of node arrays.
      */
-    private static void updateNodeCachedAddresses(final ArrayList<Node> flatNodes) {
-        for (final Node n : flatNodes) {
-            n.mCachedAddressBeforeUpdate = n.mCachedAddressAfterUpdate;
-            for (final CharGroup g : n.mData) {
+    private static void updateNodeArraysCachedAddresses(final ArrayList<PtNodeArray> flatNodes) {
+        for (final PtNodeArray nodeArray : flatNodes) {
+            nodeArray.mCachedAddressBeforeUpdate = nodeArray.mCachedAddressAfterUpdate;
+            for (final CharGroup g : nodeArray.mData) {
                 g.mCachedAddressBeforeUpdate = g.mCachedAddressAfterUpdate;
             }
         }
@@ -391,11 +403,11 @@ public class BinaryDictEncoder {
      * The parent addresses are used by some binary formats at write-to-disk time. Not all formats
      * need them. In particular, version 2 does not need them, and version 3 does.
      *
-     * @param flatNodes the flat array of nodes to fill in
+     * @param flatNodes the flat array of node arrays to fill in
      */
-    private static void computeParentAddresses(final ArrayList<Node> flatNodes) {
-        for (final Node node : flatNodes) {
-            for (final CharGroup group : node.mData) {
+    private static void computeParentAddresses(final ArrayList<PtNodeArray> flatNodes) {
+        for (final PtNodeArray nodeArray : flatNodes) {
+            for (final CharGroup group : nodeArray.mData) {
                 if (null != group.mChildren) {
                     // Assign my address to children's parent address
                     // Here BeforeUpdate and AfterUpdate addresses have the same value, so it
@@ -408,25 +420,25 @@ public class BinaryDictEncoder {
     }
 
     /**
-     * Compute the addresses and sizes of an ordered node array.
+     * Compute the addresses and sizes of an ordered list of node arrays.
      *
-     * This method takes a node array and will update its cached address and size values
-     * so that they can be written into a file. It determines the smallest size each of the
-     * nodes can be given the addresses of its children and attributes, and store that into
+     * This method takes a list of node arrays and will update their cached address and size
+     * values so that they can be written into a file. It determines the smallest size each of the
+     * nodes arrays can be given the addresses of its children and attributes, and store that into
      * each node.
      * The order of the node is given by the order of the array. This method makes no effort
      * to find a good order; it only mechanically computes the size this order results in.
      *
      * @param dict the dictionary
-     * @param flatNodes the ordered array of nodes
+     * @param flatNodes the ordered list of nodes arrays
      * @param formatOptions file format options.
      * @return the same array it was passed. The nodes have been updated for address and size.
      */
-    private static ArrayList<Node> computeAddresses(final FusionDictionary dict,
-            final ArrayList<Node> flatNodes, final FormatOptions formatOptions) {
+    private static ArrayList<PtNodeArray> computeAddresses(final FusionDictionary dict,
+            final ArrayList<PtNodeArray> flatNodes, final FormatOptions formatOptions) {
         // First get the worst possible sizes and offsets
-        for (final Node n : flatNodes) calculateNodeMaximumSize(n, formatOptions);
-        final int offset = initializeNodesCachedAddresses(flatNodes, formatOptions);
+        for (final PtNodeArray n : flatNodes) calculateNodeArrayMaximumSize(n, formatOptions);
+        final int offset = initializeNodeArraysCachedAddresses(flatNodes, formatOptions);
 
         MakedictLog.i("Compressing the array addresses. Original size : " + offset);
         MakedictLog.i("(Recursively seen size : " + offset + ")");
@@ -435,17 +447,19 @@ public class BinaryDictEncoder {
         boolean changesDone = false;
         do {
             changesDone = false;
-            int nodeStartOffset = 0;
-            for (final Node n : flatNodes) {
-                n.mCachedAddressAfterUpdate = nodeStartOffset;
-                final int oldNodeSize = n.mCachedSize;
-                final boolean changed = computeActualNodeSize(n, dict, formatOptions);
-                final int newNodeSize = n.mCachedSize;
-                if (oldNodeSize < newNodeSize) throw new RuntimeException("Increased size ?!");
-                nodeStartOffset += newNodeSize;
+            int nodeArrayStartOffset = 0;
+            for (final PtNodeArray nodeArray : flatNodes) {
+                nodeArray.mCachedAddressAfterUpdate = nodeArrayStartOffset;
+                final int oldNodeArraySize = nodeArray.mCachedSize;
+                final boolean changed = computeActualNodeArraySize(nodeArray, dict, formatOptions);
+                final int newNodeArraySize = nodeArray.mCachedSize;
+                if (oldNodeArraySize < newNodeArraySize) {
+                    throw new RuntimeException("Increased size ?!");
+                }
+                nodeArrayStartOffset += newNodeArraySize;
                 changesDone |= changed;
             }
-            updateNodeCachedAddresses(flatNodes);
+            updateNodeArraysCachedAddresses(flatNodes);
             ++passes;
             if (passes > MAX_PASSES) throw new RuntimeException("Too many passes - probably a bug");
         } while (changesDone);
@@ -453,10 +467,10 @@ public class BinaryDictEncoder {
         if (formatOptions.mSupportsDynamicUpdate) {
             computeParentAddresses(flatNodes);
         }
-        final Node lastNode = flatNodes.get(flatNodes.size() - 1);
+        final PtNodeArray lastNodeArray = flatNodes.get(flatNodes.size() - 1);
         MakedictLog.i("Compression complete in " + passes + " passes.");
         MakedictLog.i("After address compression : "
-                + (lastNode.mCachedAddressAfterUpdate + lastNode.mCachedSize));
+                + (lastNodeArray.mCachedAddressAfterUpdate + lastNodeArray.mCachedSize));
 
         return flatNodes;
     }
@@ -464,25 +478,25 @@ public class BinaryDictEncoder {
     /**
      * Sanity-checking method.
      *
-     * This method checks an array of node for juxtaposition, that is, it will do
-     * nothing if each node's cached address is actually the previous node's address
+     * This method checks a list of node arrays for juxtaposition, that is, it will do
+     * nothing if each node array's cached address is actually the previous node array's address
      * plus the previous node's size.
      * If this is not the case, it will throw an exception.
      *
-     * @param array the array node to check
+     * @param arrays the list of node arrays to check
      */
-    private static void checkFlatNodeArray(final ArrayList<Node> array) {
+    private static void checkFlatNodeArrayList(final ArrayList<PtNodeArray> arrays) {
         int offset = 0;
         int index = 0;
-        for (final Node n : array) {
+        for (final PtNodeArray nodeArray : arrays) {
             // BeforeUpdate and AfterUpdate addresses are the same here, so it does not matter
             // which we use.
-            if (n.mCachedAddressAfterUpdate != offset) {
+            if (nodeArray.mCachedAddressAfterUpdate != offset) {
                 throw new RuntimeException("Wrong address for node " + index
-                        + " : expected " + offset + ", got " + n.mCachedAddressAfterUpdate);
+                        + " : expected " + offset + ", got " + nodeArray.mCachedAddressAfterUpdate);
             }
             ++index;
-            offset += n.mCachedSize;
+            offset += nodeArray.mCachedSize;
         }
     }
 
@@ -707,26 +721,23 @@ public class BinaryDictEncoder {
     }
 
     /**
-     * Write a node to memory. The node is expected to have its final position cached.
+     * Write a node array to memory. The node array is expected to have its final position cached.
      *
-     * This can be an empty map, but the more is inside the faster the lookups will be. It can
-     * be carried on as long as nodes do not move.
-     *
-     * @param dict the dictionary the node is a part of (for relative offsets).
+     * @param dict the dictionary the node array is a part of (for relative offsets).
      * @param buffer the memory buffer to write to.
-     * @param node the node to write.
+     * @param nodeArray the node array to write.
      * @param formatOptions file format options.
      * @return the address of the END of the node.
      */
     @SuppressWarnings("unused")
     private static int writePlacedNode(final FusionDictionary dict, byte[] buffer,
-            final Node node, final FormatOptions formatOptions) {
+            final PtNodeArray nodeArray, final FormatOptions formatOptions) {
         // TODO: Make the code in common with BinaryDictIOUtils#writeCharGroup
-        int index = node.mCachedAddressAfterUpdate;
+        int index = nodeArray.mCachedAddressAfterUpdate;
 
-        final int groupCount = node.mData.size();
-        final int countSize = getGroupCountSize(node);
-        final int parentAddress = node.mCachedParentAddress;
+        final int groupCount = nodeArray.mData.size();
+        final int countSize = getGroupCountSize(nodeArray);
+        final int parentAddress = nodeArray.mCachedParentAddress;
         if (1 == countSize) {
             buffer[index++] = (byte)groupCount;
         } else if (2 == countSize) {
@@ -739,7 +750,7 @@ public class BinaryDictEncoder {
         }
         int groupAddress = index;
         for (int i = 0; i < groupCount; ++i) {
-            final CharGroup group = node.mData.get(i);
+            final CharGroup group = nodeArray.mData.get(i);
             if (index != group.mCachedAddressAfterUpdate) {
                 throw new RuntimeException("Bug: write index is not the same as the cached address "
                         + "of the group : " + index + " <> " + group.mCachedAddressAfterUpdate);
@@ -762,7 +773,7 @@ public class BinaryDictEncoder {
                 index = writeParentAddress(buffer, index, parentAddress, formatOptions);
             } else {
                 index = writeParentAddress(buffer, index, parentAddress
-                        + (node.mCachedAddressAfterUpdate - group.mCachedAddressAfterUpdate),
+                        + (nodeArray.mCachedAddressAfterUpdate - group.mCachedAddressAfterUpdate),
                         formatOptions);
             }
 
@@ -812,7 +823,7 @@ public class BinaryDictEncoder {
                 while (bigramIterator.hasNext()) {
                     final WeightedString bigram = bigramIterator.next();
                     final CharGroup target =
-                            FusionDictionary.findWordInTree(dict.mRoot, bigram.mWord);
+                            FusionDictionary.findWordInTree(dict.mRootNodeArray, bigram.mWord);
                     final int addressOfBigram = target.mCachedAddressAfterUpdate;
                     final int unigramFrequencyForThisWord = target.mFrequency;
                     ++groupAddress;
@@ -832,57 +843,58 @@ public class BinaryDictEncoder {
                     = FormatSpec.NO_FORWARD_LINK_ADDRESS;
             index += FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
         }
-        if (index != node.mCachedAddressAfterUpdate + node.mCachedSize) throw new RuntimeException(
-                "Not the same size : written "
-                + (index - node.mCachedAddressAfterUpdate) + " bytes from a node that should have "
-                + node.mCachedSize + " bytes");
+        if (index != nodeArray.mCachedAddressAfterUpdate + nodeArray.mCachedSize) {
+            throw new RuntimeException(
+                    "Not the same size : written " + (index - nodeArray.mCachedAddressAfterUpdate)
+                     + " bytes from a node that should have " + nodeArray.mCachedSize + " bytes");
+        }
         return index;
     }
 
     /**
-     * Dumps a collection of useful statistics about a node array.
+     * Dumps a collection of useful statistics about a list of node arrays.
      *
      * This prints purely informative stuff, like the total estimated file size, the
-     * number of nodes, of character groups, the repartition of each address size, etc
+     * number of node arrays, of character groups, the repartition of each address size, etc
      *
-     * @param nodes the node array.
+     * @param nodeArrays the list of node arrays.
      */
-    private static void showStatistics(ArrayList<Node> nodes) {
+    private static void showStatistics(ArrayList<PtNodeArray> nodeArrays) {
         int firstTerminalAddress = Integer.MAX_VALUE;
         int lastTerminalAddress = Integer.MIN_VALUE;
         int size = 0;
         int charGroups = 0;
         int maxGroups = 0;
         int maxRuns = 0;
-        for (final Node n : nodes) {
-            if (maxGroups < n.mData.size()) maxGroups = n.mData.size();
-            for (final CharGroup cg : n.mData) {
+        for (final PtNodeArray nodeArray : nodeArrays) {
+            if (maxGroups < nodeArray.mData.size()) maxGroups = nodeArray.mData.size();
+            for (final CharGroup cg : nodeArray.mData) {
                 ++charGroups;
                 if (cg.mChars.length > maxRuns) maxRuns = cg.mChars.length;
                 if (cg.mFrequency >= 0) {
-                    if (n.mCachedAddressAfterUpdate < firstTerminalAddress)
-                        firstTerminalAddress = n.mCachedAddressAfterUpdate;
-                    if (n.mCachedAddressAfterUpdate > lastTerminalAddress)
-                        lastTerminalAddress = n.mCachedAddressAfterUpdate;
+                    if (nodeArray.mCachedAddressAfterUpdate < firstTerminalAddress)
+                        firstTerminalAddress = nodeArray.mCachedAddressAfterUpdate;
+                    if (nodeArray.mCachedAddressAfterUpdate > lastTerminalAddress)
+                        lastTerminalAddress = nodeArray.mCachedAddressAfterUpdate;
                 }
             }
-            if (n.mCachedAddressAfterUpdate + n.mCachedSize > size) {
-                size = n.mCachedAddressAfterUpdate + n.mCachedSize;
+            if (nodeArray.mCachedAddressAfterUpdate + nodeArray.mCachedSize > size) {
+                size = nodeArray.mCachedAddressAfterUpdate + nodeArray.mCachedSize;
             }
         }
         final int[] groupCounts = new int[maxGroups + 1];
         final int[] runCounts = new int[maxRuns + 1];
-        for (final Node n : nodes) {
-            ++groupCounts[n.mData.size()];
-            for (final CharGroup cg : n.mData) {
+        for (final PtNodeArray nodeArray : nodeArrays) {
+            ++groupCounts[nodeArray.mData.size()];
+            for (final CharGroup cg : nodeArray.mData) {
                 ++runCounts[cg.mChars.length];
             }
         }
 
         MakedictLog.i("Statistics:\n"
                 + "  total file size " + size + "\n"
-                + "  " + nodes.size() + " nodes\n"
-                + "  " + charGroups + " groups (" + ((float)charGroups / nodes.size())
+                + "  " + nodeArrays.size() + " node arrays\n"
+                + "  " + charGroups + " groups (" + ((float)charGroups / nodeArrays.size())
                         + " groups per node)\n"
                 + "  first terminal at " + firstTerminalAddress + "\n"
                 + "  last terminal at " + lastTerminalAddress + "\n"
@@ -909,11 +921,12 @@ public class BinaryDictEncoder {
             final FusionDictionary dict, final FormatOptions formatOptions)
             throws IOException, UnsupportedFormatException {
 
-        // Addresses are limited to 3 bytes, but since addresses can be relative to each node, the
-        // structure itself is not limited to 16MB. However, if it is over 16MB deciding the order
-        // of the nodes becomes a quite complicated problem, because though the dictionary itself
-        // does not have a size limit, each node must still be within 16MB of all its children and
-        // parents. As long as this is ensured, the dictionary file may grow to any size.
+        // Addresses are limited to 3 bytes, but since addresses can be relative to each node
+        // array, the structure itself is not limited to 16MB. However, if it is over 16MB deciding
+        // the order of the node arrays becomes a quite complicated problem, because though the
+        // dictionary itself does not have a size limit, each node array must still be within 16MB
+        // of all its children and parents. As long as this is ensured, the dictionary file may
+        // grow to any size.
 
         final int version = formatOptions.mVersion;
         if (version < FormatSpec.MINIMUM_SUPPORTED_VERSION
@@ -964,23 +977,23 @@ public class BinaryDictEncoder {
 
         // Leave the choice of the optimal node order to the flattenTree function.
         MakedictLog.i("Flattening the tree...");
-        ArrayList<Node> flatNodes = flattenTree(dict.mRoot);
+        ArrayList<PtNodeArray> flatNodes = flattenTree(dict.mRootNodeArray);
 
         MakedictLog.i("Computing addresses...");
         computeAddresses(dict, flatNodes, formatOptions);
         MakedictLog.i("Checking array...");
-        if (DBG) checkFlatNodeArray(flatNodes);
+        if (DBG) checkFlatNodeArrayList(flatNodes);
 
         // Create a buffer that matches the final dictionary size.
-        final Node lastNode = flatNodes.get(flatNodes.size() - 1);
-        final int bufferSize = lastNode.mCachedAddressAfterUpdate + lastNode.mCachedSize;
+        final PtNodeArray lastNodeArray = flatNodes.get(flatNodes.size() - 1);
+        final int bufferSize = lastNodeArray.mCachedAddressAfterUpdate + lastNodeArray.mCachedSize;
         final byte[] buffer = new byte[bufferSize];
         int index = 0;
 
         MakedictLog.i("Writing file...");
         int dataEndOffset = 0;
-        for (Node n : flatNodes) {
-            dataEndOffset = writePlacedNode(dict, buffer, n, formatOptions);
+        for (PtNodeArray nodeArray : flatNodes) {
+            dataEndOffset = writePlacedNode(dict, buffer, nodeArray, formatOptions);
         }
 
         if (DBG) showStatistics(flatNodes);
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
index c013013e6..476d51b8e 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
@@ -59,7 +59,7 @@ public final class BinaryDictIOUtils {
     }
 
     /**
-     * Tours all node without recursive call.
+     * Retrieves all node arrays without recursive call.
      */
     private static void readUnigramsAndBigramsBinaryInner(
             final FusionDictionaryBufferInterface buffer, final int headerSize,
@@ -116,7 +116,7 @@ public final class BinaryDictIOUtils {
                 if (formatOptions.mSupportsDynamicUpdate) {
                     final int forwardLinkAddress = buffer.readUnsignedInt24();
                     if (forwardLinkAddress != FormatSpec.NO_FORWARD_LINK_ADDRESS) {
-                        // the node has a forward link.
+                        // The node array has a forward link.
                         p.mNumOfCharGroup = Position.NOT_READ_GROUPCOUNT;
                         p.mAddress = forwardLinkAddress;
                     } else {
@@ -126,7 +126,7 @@ public final class BinaryDictIOUtils {
                     stack.pop();
                 }
             } else {
-                // the node has more groups.
+                // The node array has more groups.
                 p.mAddress = buffer.position();
             }
 
@@ -139,14 +139,14 @@ public final class BinaryDictIOUtils {
 
     /**
      * Reads unigrams and bigrams from the binary file.
-     * Doesn't make the memory representation of the dictionary.
+     * Doesn't store a full memory representation of the dictionary.
      *
      * @param reader the reader.
      * @param words the map to store the address as a key and the word as a value.
      * @param frequencies the map to store the address as a key and the frequency as a value.
      * @param bigrams the map to store the address as a key and the list of address as a value.
-     * @throws IOException
-     * @throws UnsupportedFormatException
+     * @throws IOException if the file can't be read.
+     * @throws UnsupportedFormatException if the format of the file is not recognized.
      */
     public static void readUnigramsAndBigramsBinary(final BinaryDictReader reader,
             final Map<Integer, String> words, final Map<Integer, Integer> frequencies,
@@ -165,8 +165,8 @@ public final class BinaryDictIOUtils {
      * @param buffer the buffer to read.
      * @param word the word we search for.
      * @return the address of the terminal node.
-     * @throws IOException
-     * @throws UnsupportedFormatException
+     * @throws IOException if the file can't be read.
+     * @throws UnsupportedFormatException if the format of the file is not recognized.
      */
     @UsedForTesting
     public static int getTerminalPosition(final FusionDictionaryBufferInterface buffer,
@@ -224,9 +224,9 @@ public final class BinaryDictIOUtils {
                 }
 
                 // If we found the next char group, it is under the file pointer.
-                // But if not, we are at the end of this node so we expect to have
+                // But if not, we are at the end of this node array so we expect to have
                 // a forward link address that we need to consult and possibly resume
-                // search on the next node in the linked list.
+                // search on the next node array in the linked list.
                 if (foundNextCharGroup) break;
                 if (!header.mFormatOptions.mSupportsDynamicUpdate) {
                     return FormatSpec.NOT_VALID_WORD;
@@ -365,9 +365,10 @@ public final class BinaryDictIOUtils {
     }
 
     /**
-     * Write a char group to an output stream.
-     * A char group is an in-memory representation of a node in trie.
-     * A char group info is an on-disk representation of a node.
+     * Write a char group to an output stream from a CharGroupInfo.
+     * A char group is an in-memory representation of a node in the patricia trie.
+     * A char group info is a container for low-level information about how the
+     * char group is stored in the binary format.
      *
      * @param destination the stream to write.
      * @param info the char group info to be written.
@@ -427,7 +428,7 @@ public final class BinaryDictIOUtils {
 
         if (info.mBigrams != null) {
             // TODO: Consolidate this code with the code that computes the size of the bigram list
-            //        in BinaryDictEncoder#computeActualNodeSize
+            //        in BinaryDictEncoder#computeActualNodeArraySize
             for (int i = 0; i < info.mBigrams.size(); ++i) {
 
                 final int bigramFrequency = info.mBigrams.get(i).mFrequency;
@@ -479,14 +480,14 @@ public final class BinaryDictIOUtils {
     }
 
     /**
-     * Write a node to the stream.
+     * Write a node array to the stream.
      *
      * @param destination the stream to write.
-     * @param infos groups to be written.
+     * @param infos an array of CharGroupInfo to be written.
      * @return the size written, in bytes.
      * @throws IOException
      */
-    static int writeNode(final OutputStream destination, final CharGroupInfo[] infos)
+    static int writeNodes(final OutputStream destination, final CharGroupInfo[] infos)
             throws IOException {
         int size = getGroupCountSize(infos.length);
         switch (getGroupCountSize(infos.length)) {
@@ -604,12 +605,12 @@ public final class BinaryDictIOUtils {
     public static int getGroupCountSize(final int count) {
         if (FormatSpec.MAX_CHARGROUPS_FOR_ONE_BYTE_CHARGROUP_COUNT >= count) {
             return 1;
-        } else if (FormatSpec.MAX_CHARGROUPS_IN_A_NODE >= count) {
+        } else if (FormatSpec.MAX_CHARGROUPS_IN_A_PT_NODE_ARRAY >= count) {
             return 2;
         } else {
             throw new RuntimeException("Can't have more than "
-                    + FormatSpec.MAX_CHARGROUPS_IN_A_NODE + " groups in a node (found " + count
-                    + ")");
+                    + FormatSpec.MAX_CHARGROUPS_IN_A_PT_NODE_ARRAY + " groups in a node (found "
+                    + count + ")");
         }
     }
 
diff --git a/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java b/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java
index 4dbfcb77d..5d116d79c 100644
--- a/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java
+++ b/java/src/com/android/inputmethod/latin/makedict/DynamicBinaryDictIOUtils.java
@@ -86,7 +86,7 @@ public final class DynamicBinaryDictIOUtils {
         }
         final int flags = buffer.readUnsignedByte();
         if (BinaryDictIOUtils.isMovedGroup(flags, formatOptions)) {
-            // if the group is moved, the parent address is stored in the destination group.
+            // If the group is moved, the parent address is stored in the destination group.
             // We are guaranteed to process the destination group later, so there is no need to
             // update anything here.
             buffer.position(originalPosition);
@@ -101,10 +101,10 @@ public final class DynamicBinaryDictIOUtils {
     }
 
     /**
-     * Update parent addresses in a Node that is referred to by nodeOriginAddress.
+     * Update parent addresses in a node array stored at nodeOriginAddress.
      *
      * @param buffer the buffer to be modified.
-     * @param nodeOriginAddress the address of a modified Node.
+     * @param nodeOriginAddress the address of the node array to update.
      * @param newParentAddress the address to be written.
      * @param formatOptions file format options.
      */
@@ -154,7 +154,7 @@ public final class DynamicBinaryDictIOUtils {
      */
     private static int moveCharGroup(final OutputStream destination,
             final FusionDictionaryBufferInterface buffer, final CharGroupInfo info,
-            final int nodeOriginAddress, final int oldGroupAddress,
+            final int nodeArrayOriginAddress, final int oldGroupAddress,
             final FormatOptions formatOptions) throws IOException {
         updateParentAddress(buffer, oldGroupAddress, buffer.limit() + 1, formatOptions);
         buffer.position(oldGroupAddress);
@@ -163,15 +163,16 @@ public final class DynamicBinaryDictIOUtils {
         buffer.put((byte)(FormatSpec.FLAG_IS_MOVED | (currentFlags
                 & (~FormatSpec.MASK_MOVE_AND_DELETE_FLAG))));
         int size = FormatSpec.GROUP_FLAGS_SIZE;
-        updateForwardLink(buffer, nodeOriginAddress, buffer.limit(), formatOptions);
-        size += BinaryDictIOUtils.writeNode(destination, new CharGroupInfo[] { info });
+        updateForwardLink(buffer, nodeArrayOriginAddress, buffer.limit(), formatOptions);
+        size += BinaryDictIOUtils.writeNodes(destination, new CharGroupInfo[] { info });
         return size;
     }
+
     @SuppressWarnings("unused")
     private static void updateForwardLink(final FusionDictionaryBufferInterface buffer,
-            final int nodeOriginAddress, final int newNodeAddress,
+            final int nodeArrayOriginAddress, final int newNodeArrayAddress,
             final FormatOptions formatOptions) {
-        buffer.position(nodeOriginAddress);
+        buffer.position(nodeArrayOriginAddress);
         int jumpCount = 0;
         while (jumpCount++ < MAX_JUMPS) {
             final int count = BinaryDictDecoder.readCharGroupCount(buffer);
@@ -179,7 +180,7 @@ public final class DynamicBinaryDictIOUtils {
             final int forwardLinkAddress = buffer.readUnsignedInt24();
             if (forwardLinkAddress == FormatSpec.NO_FORWARD_LINK_ADDRESS) {
                 buffer.position(buffer.position() - FormatSpec.FORWARD_LINK_ADDRESS_SIZE);
-                BinaryDictIOUtils.writeSInt24ToBuffer(buffer, newNodeAddress);
+                BinaryDictIOUtils.writeSInt24ToBuffer(buffer, newNodeArrayAddress);
                 return;
             }
             buffer.position(forwardLinkAddress);
@@ -190,57 +191,59 @@ public final class DynamicBinaryDictIOUtils {
     }
 
     /**
-     * Move a group that is referred to by oldGroupOrigin to the tail of the file.
-     * And set the children address to the byte after the group.
+     * Move a group that is referred to by oldGroupOrigin to the tail of the file, and set the
+     * children address to the byte after the group
      *
-     * @param nodeOrigin the address of the tail of the file.
-     * @param characters
-     * @param length
-     * @param flags
-     * @param frequency
-     * @param parentAddress
-     * @param shortcutTargets
-     * @param bigrams
+     * @param fileEndAddress the address of the tail of the file.
+     * @param codePoints the characters to put inside the group.
+     * @param length how many code points to read from codePoints.
+     * @param flags the flags for this group.
+     * @param frequency the frequency of this terminal.
+     * @param parentAddress the address of the parent group of this group.
+     * @param shortcutTargets the shortcut targets for this group.
+     * @param bigrams the bigrams for this group.
      * @param destination the stream representing the tail of the file.
      * @param buffer the buffer representing the (constant-size) body of the file.
-     * @param oldNodeOrigin
-     * @param oldGroupOrigin
-     * @param formatOptions
+     * @param oldNodeArrayOrigin the origin of the old node array this group was a part of.
+     * @param oldGroupOrigin the old origin where this group used to be stored.
+     * @param formatOptions format options for this dictionary.
      * @return the size written, in bytes.
-     * @throws IOException
+     * @throws IOException if the file can't be accessed
      */
-    private static int moveGroup(final int nodeOrigin, final int[] characters, final int length,
-            final int flags, final int frequency, final int parentAddress,
+    private static int moveGroup(final int fileEndAddress, final int[] codePoints,
+            final int length, final int flags, final int frequency, final int parentAddress,
             final ArrayList<WeightedString> shortcutTargets,
             final ArrayList<PendingAttribute> bigrams, final OutputStream destination,
-            final FusionDictionaryBufferInterface buffer, final int oldNodeOrigin,
+            final FusionDictionaryBufferInterface buffer, final int oldNodeArrayOrigin,
             final int oldGroupOrigin, final FormatOptions formatOptions) throws IOException {
         int size = 0;
-        final int newGroupOrigin = nodeOrigin + 1;
-        final int[] writtenCharacters = Arrays.copyOfRange(characters, 0, length);
+        final int newGroupOrigin = fileEndAddress + 1;
+        final int[] writtenCharacters = Arrays.copyOfRange(codePoints, 0, length);
         final CharGroupInfo tmpInfo = new CharGroupInfo(newGroupOrigin, -1 /* endAddress */,
                 flags, writtenCharacters, frequency, parentAddress, FormatSpec.NO_CHILDREN_ADDRESS,
                 shortcutTargets, bigrams);
         size = BinaryDictIOUtils.computeGroupSize(tmpInfo, formatOptions);
         final CharGroupInfo newInfo = new CharGroupInfo(newGroupOrigin, newGroupOrigin + size,
                 flags, writtenCharacters, frequency, parentAddress,
-                nodeOrigin + 1 + size + FormatSpec.FORWARD_LINK_ADDRESS_SIZE, shortcutTargets,
+                fileEndAddress + 1 + size + FormatSpec.FORWARD_LINK_ADDRESS_SIZE, shortcutTargets,
                 bigrams);
-        moveCharGroup(destination, buffer, newInfo, oldNodeOrigin, oldGroupOrigin, formatOptions);
+        moveCharGroup(destination, buffer, newInfo, oldNodeArrayOrigin, oldGroupOrigin,
+                formatOptions);
         return 1 + size + FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
     }
 
     /**
      * Insert a word into a binary dictionary.
      *
-     * @param buffer
-     * @param destination
-     * @param word
-     * @param frequency
-     * @param bigramStrings
-     * @param shortcuts
-     * @throws IOException
-     * @throws UnsupportedFormatException
+     * @param buffer the buffer containing the existing dictionary.
+     * @param destination a stream to the underlying file, with the pointer at the end of the file.
+     * @param word the word to insert.
+     * @param frequency the frequency of the new word.
+     * @param bigramStrings bigram list, or null if none.
+     * @param shortcuts shortcut list, or null if none.
+     * @param isBlackListEntry whether this should be a blacklist entry.
+     * @throws IOException if the file can't be accessed.
+     * @throws UnsupportedFormatException if the existing dictionary is in an unexpected format.
      */
     // TODO: Support batch insertion.
     // TODO: Remove @UsedForTesting once UserHistoryDictionary is implemented by BinaryDictionary.
@@ -323,7 +326,7 @@ public final class DynamicBinaryDictIOUtils {
                                 currentInfo.mFlags, characters2, currentInfo.mFrequency,
                                 newNodeAddress + 1, currentInfo.mChildrenAddress,
                                 currentInfo.mShortcutTargets, currentInfo.mBigrams);
-                        BinaryDictIOUtils.writeNode(destination, new CharGroupInfo[] { newInfo2 });
+                        BinaryDictIOUtils.writeNodes(destination, new CharGroupInfo[] { newInfo2 });
                         return;
                     } else if (codePoints[wordPos + p] != currentInfo.mCharacters[p]) {
                         if (p > 0) {
@@ -386,7 +389,7 @@ public final class DynamicBinaryDictIOUtils {
                                     newNodeAddress + written, -1 /* endAddress */, flags,
                                     newCharacters, frequency, newNodeAddress + 1,
                                     FormatSpec.NO_CHILDREN_ADDRESS, shortcuts, bigrams);
-                            BinaryDictIOUtils.writeNode(destination,
+                            BinaryDictIOUtils.writeNodes(destination,
                                     new CharGroupInfo[] { suffixInfo, newInfo });
                             return;
                         }
@@ -438,7 +441,7 @@ public final class DynamicBinaryDictIOUtils {
                         final CharGroupInfo newInfo = new CharGroupInfo(newGroupAddress, -1, flags,
                                 characters, frequency, address, FormatSpec.NO_CHILDREN_ADDRESS,
                                 shortcuts, bigrams);
-                        BinaryDictIOUtils.writeNode(destination, new CharGroupInfo[] { newInfo });
+                        BinaryDictIOUtils.writeNodes(destination, new CharGroupInfo[] { newInfo });
                         return;
                     }
                     buffer.position(currentInfo.mChildrenAddress);
@@ -482,7 +485,7 @@ public final class DynamicBinaryDictIOUtils {
                 final CharGroupInfo newInfo = new CharGroupInfo(newNodeAddress + 1,
                         -1 /* endAddress */, flags, characters, frequency, nodeParentAddress,
                         FormatSpec.NO_CHILDREN_ADDRESS, shortcuts, bigrams);
-                BinaryDictIOUtils.writeNode(destination, new CharGroupInfo[]{ newInfo });
+                BinaryDictIOUtils.writeNodes(destination, new CharGroupInfo[]{ newInfo });
                 return;
             } else {
                 depth--;
diff --git a/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java b/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
index 9af66ed4c..5e331219c 100644
--- a/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
+++ b/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
@@ -60,7 +60,7 @@ public final class FormatSpec {
      */
 
     /*
-     * Array of Node(FusionDictionary.Node) layout is as follows:
+     * Node array (FusionDictionary.PtNodeArray) layout is as follows:
      *
      * g |
      * r | the number of groups, 1 or 2 bytes.
@@ -86,7 +86,7 @@ public final class FormatSpec {
      * linkaddress
      */
 
-    /* Node(CharGroup) layout is as follows:
+    /* Node (FusionDictionary.CharGroup) layout is as follows:
      *   | IF !SUPPORTS_DYNAMIC_UPDATE
      *   |   addressType                         xx     : mask with MASK_GROUP_ADDRESS_TYPE
      *   |                           2 bits, 00 = no children : FLAG_GROUP_ADDRESS_TYPE_NOADDRESS
@@ -251,7 +251,7 @@ public final class FormatSpec {
     static final int INVALID_CHARACTER = -1;
 
     static final int MAX_CHARGROUPS_FOR_ONE_BYTE_CHARGROUP_COUNT = 0x7F; // 127
-    static final int MAX_CHARGROUPS_IN_A_NODE = 0x7FFF; // 32767
+    static final int MAX_CHARGROUPS_IN_A_PT_NODE_ARRAY = 0x7FFF; // 32767
     static final int MAX_BIGRAMS_IN_A_GROUP = 10000;
 
     static final int MAX_TERMINAL_FREQUENCY = 255;
diff --git a/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java b/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java
index 118dc22b8..fce1c5cdd 100644
--- a/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java
+++ b/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java
@@ -37,14 +37,14 @@ public final class FusionDictionary implements Iterable<Word> {
     private static int CHARACTER_NOT_FOUND_INDEX = -1;
 
     /**
-     * A node of the dictionary, containing several CharGroups.
+     * A node array of the dictionary, containing several CharGroups.
      *
-     * A node is but an ordered array of CharGroups, which essentially contain all the
+     * A PtNodeArray is but an ordered array of CharGroups, which essentially contain all the
      * real information.
      * This class also contains fields to cache size and address, to help with binary
      * generation.
      */
-    public static final class Node {
+    public static final class PtNodeArray {
         ArrayList<CharGroup> mData;
         // To help with binary generation
         int mCachedSize = Integer.MIN_VALUE;
@@ -57,10 +57,10 @@ public final class FusionDictionary implements Iterable<Word> {
         int mCachedAddressAfterUpdate = Integer.MIN_VALUE;
         int mCachedParentAddress = 0;
 
-        public Node() {
+        public PtNodeArray() {
             mData = new ArrayList<CharGroup>();
         }
-        public Node(ArrayList<CharGroup> data) {
+        public PtNodeArray(ArrayList<CharGroup> data) {
             mData = data;
         }
     }
@@ -98,7 +98,7 @@ public final class FusionDictionary implements Iterable<Word> {
      * This is the central class of the in-memory representation. A CharGroup is what can
      * be seen as a traditional "trie node", except it can hold several characters at the
      * same time. A CharGroup essentially represents one or several characters in the middle
-     * of the trie trie; as such, it can be a terminal, and it can have children.
+     * of the trie tree; as such, it can be a terminal, and it can have children.
      * In this in-memory representation, whether the CharGroup is a terminal or not is represented
      * in the frequency, where NOT_A_TERMINAL (= -1) means this is not a terminal and any other
      * value is the frequency of this terminal. A terminal may have non-null shortcuts and/or
@@ -110,7 +110,7 @@ public final class FusionDictionary implements Iterable<Word> {
         ArrayList<WeightedString> mShortcutTargets;
         ArrayList<WeightedString> mBigrams;
         int mFrequency; // NOT_A_TERMINAL == mFrequency indicates this is not a terminal.
-        Node mChildren;
+        PtNodeArray mChildren;
         boolean mIsNotAWord; // Only a shortcut
         boolean mIsBlacklistEntry;
         // mCachedSize and mCachedAddressBefore/AfterUpdate are helpers for binary dictionary
@@ -137,7 +137,8 @@ public final class FusionDictionary implements Iterable<Word> {
 
         public CharGroup(final int[] chars, final ArrayList<WeightedString> shortcutTargets,
                 final ArrayList<WeightedString> bigrams, final int frequency,
-                final boolean isNotAWord, final boolean isBlacklistEntry, final Node children) {
+                final boolean isNotAWord, final boolean isBlacklistEntry,
+                final PtNodeArray children) {
             mChars = chars;
             mFrequency = frequency;
             mShortcutTargets = shortcutTargets;
@@ -149,7 +150,7 @@ public final class FusionDictionary implements Iterable<Word> {
 
         public void addChild(CharGroup n) {
             if (null == mChildren) {
-                mChildren = new Node();
+                mChildren = new PtNodeArray();
             }
             mChildren.mData.add(n);
         }
@@ -344,10 +345,10 @@ public final class FusionDictionary implements Iterable<Word> {
     }
 
     public final DictionaryOptions mOptions;
-    public final Node mRoot;
+    public final PtNodeArray mRootNodeArray;
 
-    public FusionDictionary(final Node root, final DictionaryOptions options) {
-        mRoot = root;
+    public FusionDictionary(final PtNodeArray rootNodeArray, final DictionaryOptions options) {
+        mRootNodeArray = rootNodeArray;
         mOptions = options;
     }
 
@@ -406,13 +407,13 @@ public final class FusionDictionary implements Iterable<Word> {
     }
 
     /**
-     * Sanity check for a node.
+     * Sanity check for a node array.
      *
-     * This method checks that all CharGroups in a node are ordered as expected.
+     * This method checks that all CharGroups in a node array are ordered as expected.
      * If they are, nothing happens. If they aren't, an exception is thrown.
      */
-    private void checkStack(Node node) {
-        ArrayList<CharGroup> stack = node.mData;
+    private void checkStack(PtNodeArray nodeArray) {
+        ArrayList<CharGroup> stack = nodeArray.mData;
         int lastValue = -1;
         for (int i = 0; i < stack.size(); ++i) {
             int currentValue = stack.get(i).mChars[0];
@@ -431,16 +432,16 @@ public final class FusionDictionary implements Iterable<Word> {
      * @param frequency the bigram frequency
      */
     public void setBigram(final String word1, final String word2, final int frequency) {
-        CharGroup charGroup = findWordInTree(mRoot, word1);
+        CharGroup charGroup = findWordInTree(mRootNodeArray, word1);
         if (charGroup != null) {
-            final CharGroup charGroup2 = findWordInTree(mRoot, word2);
+            final CharGroup charGroup2 = findWordInTree(mRootNodeArray, word2);
             if (charGroup2 == null) {
                 add(getCodePoints(word2), 0, null, false /* isNotAWord */,
                         false /* isBlacklistEntry */);
                 // The chargroup for the first word may have moved by the above insertion,
                 // if word1 and word2 share a common stem that happens not to have been
                 // a cutting point until now. In this case, we need to refresh charGroup.
-                charGroup = findWordInTree(mRoot, word1);
+                charGroup = findWordInTree(mRootNodeArray, word1);
             }
             charGroup.addBigram(word2, frequency);
         } else {
@@ -469,38 +470,38 @@ public final class FusionDictionary implements Iterable<Word> {
             return;
         }
 
-        Node currentNode = mRoot;
+        PtNodeArray currentNodeArray = mRootNodeArray;
         int charIndex = 0;
 
         CharGroup currentGroup = null;
         int differentCharIndex = 0; // Set by the loop to the index of the char that differs
-        int nodeIndex = findIndexOfChar(mRoot, word[charIndex]);
+        int nodeIndex = findIndexOfChar(mRootNodeArray, word[charIndex]);
         while (CHARACTER_NOT_FOUND_INDEX != nodeIndex) {
-            currentGroup = currentNode.mData.get(nodeIndex);
-            differentCharIndex = compareArrays(currentGroup.mChars, word, charIndex);
+            currentGroup = currentNodeArray.mData.get(nodeIndex);
+            differentCharIndex = compareCharArrays(currentGroup.mChars, word, charIndex);
             if (ARRAYS_ARE_EQUAL != differentCharIndex
                     && differentCharIndex < currentGroup.mChars.length) break;
             if (null == currentGroup.mChildren) break;
             charIndex += currentGroup.mChars.length;
             if (charIndex >= word.length) break;
-            currentNode = currentGroup.mChildren;
-            nodeIndex = findIndexOfChar(currentNode, word[charIndex]);
+            currentNodeArray = currentGroup.mChildren;
+            nodeIndex = findIndexOfChar(currentNodeArray, word[charIndex]);
         }
 
         if (CHARACTER_NOT_FOUND_INDEX == nodeIndex) {
             // No node at this point to accept the word. Create one.
-            final int insertionIndex = findInsertionIndex(currentNode, word[charIndex]);
+            final int insertionIndex = findInsertionIndex(currentNodeArray, word[charIndex]);
             final CharGroup newGroup = new CharGroup(
                     Arrays.copyOfRange(word, charIndex, word.length),
                     shortcutTargets, null /* bigrams */, frequency, isNotAWord, isBlacklistEntry);
-            currentNode.mData.add(insertionIndex, newGroup);
-            if (DBG) checkStack(currentNode);
+            currentNodeArray.mData.add(insertionIndex, newGroup);
+            if (DBG) checkStack(currentNodeArray);
         } else {
             // There is a word with a common prefix.
             if (differentCharIndex == currentGroup.mChars.length) {
                 if (charIndex + differentCharIndex >= word.length) {
                     // The new word is a prefix of an existing word, but the node on which it
-                    // should end already exists as is. Since the old CharNode was not a terminal,
+                    // should end already exists as is. Since the old CharGroup was not a terminal,
                     // make it one by filling in its frequency and other attributes
                     currentGroup.update(frequency, shortcutTargets, null, isNotAWord,
                             isBlacklistEntry);
@@ -511,7 +512,7 @@ public final class FusionDictionary implements Iterable<Word> {
                             Arrays.copyOfRange(word, charIndex + differentCharIndex, word.length),
                                     shortcutTargets, null /* bigrams */, frequency, isNotAWord,
                                     isBlacklistEntry);
-                    currentGroup.mChildren = new Node();
+                    currentGroup.mChildren = new PtNodeArray();
                     currentGroup.mChildren.mData.add(newNode);
                 }
             } else {
@@ -524,7 +525,7 @@ public final class FusionDictionary implements Iterable<Word> {
                 } else {
                     // Partial prefix match only. We have to replace the current node with a node
                     // containing the current prefix and create two new ones for the tails.
-                    Node newChildren = new Node();
+                    PtNodeArray newChildren = new PtNodeArray();
                     final CharGroup newOldWord = new CharGroup(
                             Arrays.copyOfRange(currentGroup.mChars, differentCharIndex,
                                     currentGroup.mChars.length), currentGroup.mShortcutTargets,
@@ -552,9 +553,9 @@ public final class FusionDictionary implements Iterable<Word> {
                                 > currentGroup.mChars[differentCharIndex] ? 1 : 0;
                         newChildren.mData.add(addIndex, newWord);
                     }
-                    currentNode.mData.set(nodeIndex, newParent);
+                    currentNodeArray.mData.set(nodeIndex, newParent);
                 }
-                if (DBG) checkStack(currentNode);
+                if (DBG) checkStack(currentNodeArray);
             }
         }
     }
@@ -576,7 +577,7 @@ public final class FusionDictionary implements Iterable<Word> {
      * @param dstOffset the offset in the right-hand side string.
      * @return the index at which the strings differ, or ARRAYS_ARE_EQUAL = 0 if they don't.
      */
-    private static int compareArrays(final int[] src, final int[] dst, int dstOffset) {
+    private static int compareCharArrays(final int[] src, final int[] dst, int dstOffset) {
         // We do NOT test the first char, because we come from a method that already
         // tested it.
         for (int i = 1; i < src.length; ++i) {
@@ -603,10 +604,10 @@ public final class FusionDictionary implements Iterable<Word> {
     final static private CharGroupComparator CHARGROUP_COMPARATOR = new CharGroupComparator();
 
     /**
-     * Finds the insertion index of a character within a node.
+     * Finds the insertion index of a character within a node array.
      */
-    private static int findInsertionIndex(final Node node, int character) {
-        final ArrayList<CharGroup> data = node.mData;
+    private static int findInsertionIndex(final PtNodeArray nodeArray, int character) {
+        final ArrayList<CharGroup> data = nodeArray.mData;
         final CharGroup reference = new CharGroup(new int[] { character },
                 null /* shortcutTargets */, null /* bigrams */, 0, false /* isNotAWord */,
                 false /* isBlacklistEntry */);
@@ -615,16 +616,16 @@ public final class FusionDictionary implements Iterable<Word> {
     }
 
     /**
-     * Find the index of a char in a node, if it exists.
+     * Find the index of a char in a node array, if it exists.
      *
-     * @param node the node to search in.
+     * @param nodeArray the node array to search in.
      * @param character the character to search for.
      * @return the position of the character if it's there, or CHARACTER_NOT_FOUND_INDEX = -1 else.
      */
-    private static int findIndexOfChar(final Node node, int character) {
-        final int insertionIndex = findInsertionIndex(node, character);
-        if (node.mData.size() <= insertionIndex) return CHARACTER_NOT_FOUND_INDEX;
-        return character == node.mData.get(insertionIndex).mChars[0] ? insertionIndex
+    private static int findIndexOfChar(final PtNodeArray nodeArray, int character) {
+        final int insertionIndex = findInsertionIndex(nodeArray, character);
+        if (nodeArray.mData.size() <= insertionIndex) return CHARACTER_NOT_FOUND_INDEX;
+        return character == nodeArray.mData.get(insertionIndex).mChars[0] ? insertionIndex
                 : CHARACTER_NOT_FOUND_INDEX;
     }
 
@@ -632,16 +633,16 @@ public final class FusionDictionary implements Iterable<Word> {
      * Helper method to find a word in a given branch.
      */
     @SuppressWarnings("unused")
-    public static CharGroup findWordInTree(Node node, final String string) {
+    public static CharGroup findWordInTree(PtNodeArray nodeArray, final String string) {
         int index = 0;
         final StringBuilder checker = DBG ? new StringBuilder() : null;
         final int[] codePoints = getCodePoints(string);
 
         CharGroup currentGroup;
         do {
-            int indexOfGroup = findIndexOfChar(node, codePoints[index]);
+            int indexOfGroup = findIndexOfChar(nodeArray, codePoints[index]);
             if (CHARACTER_NOT_FOUND_INDEX == indexOfGroup) return null;
-            currentGroup = node.mData.get(indexOfGroup);
+            currentGroup = nodeArray.mData.get(indexOfGroup);
 
             if (codePoints.length - index < currentGroup.mChars.length) return null;
             int newIndex = index;
@@ -653,9 +654,9 @@ public final class FusionDictionary implements Iterable<Word> {
 
             if (DBG) checker.append(new String(currentGroup.mChars, 0, currentGroup.mChars.length));
             if (index < codePoints.length) {
-                node = currentGroup.mChildren;
+                nodeArray = currentGroup.mChildren;
             }
-        } while (null != node && index < codePoints.length);
+        } while (null != nodeArray && index < codePoints.length);
 
         if (index < codePoints.length) return null;
         if (!currentGroup.isTerminal()) return null;
@@ -670,20 +671,20 @@ public final class FusionDictionary implements Iterable<Word> {
         if (null == s || "".equals(s)) {
             throw new RuntimeException("Can't search for a null or empty string");
         }
-        return null != findWordInTree(mRoot, s);
+        return null != findWordInTree(mRootNodeArray, s);
     }
 
     /**
      * Recursively count the number of character groups in a given branch of the trie.
      *
-     * @param node the parent node.
+     * @param nodeArray the parent node.
      * @return the number of char groups in all the branch under this node.
      */
-    public static int countCharGroups(final Node node) {
-        final int nodeSize = node.mData.size();
+    public static int countCharGroups(final PtNodeArray nodeArray) {
+        final int nodeSize = nodeArray.mData.size();
         int size = nodeSize;
         for (int i = nodeSize - 1; i >= 0; --i) {
-            CharGroup group = node.mData.get(i);
+            CharGroup group = nodeArray.mData.get(i);
             if (null != group.mChildren)
                 size += countCharGroups(group.mChildren);
         }
@@ -693,15 +694,15 @@ public final class FusionDictionary implements Iterable<Word> {
     /**
      * Recursively count the number of nodes in a given branch of the trie.
      *
-     * @param node the node to count.
+     * @param nodeArray the node array to count.
      * @return the number of nodes in this branch.
      */
-    public static int countNodes(final Node node) {
+    public static int countNodeArrays(final PtNodeArray nodeArray) {
         int size = 1;
-        for (int i = node.mData.size() - 1; i >= 0; --i) {
-            CharGroup group = node.mData.get(i);
+        for (int i = nodeArray.mData.size() - 1; i >= 0; --i) {
+            CharGroup group = nodeArray.mData.get(i);
             if (null != group.mChildren)
-                size += countNodes(group.mChildren);
+                size += countNodeArrays(group.mChildren);
         }
         return size;
     }
@@ -709,10 +710,10 @@ public final class FusionDictionary implements Iterable<Word> {
     // Recursively find out whether there are any bigrams.
     // This can be pretty expensive especially if there aren't any (we return as soon
     // as we find one, so it's much cheaper if there are bigrams)
-    private static boolean hasBigramsInternal(final Node node) {
-        if (null == node) return false;
-        for (int i = node.mData.size() - 1; i >= 0; --i) {
-            CharGroup group = node.mData.get(i);
+    private static boolean hasBigramsInternal(final PtNodeArray nodeArray) {
+        if (null == nodeArray) return false;
+        for (int i = nodeArray.mData.size() - 1; i >= 0; --i) {
+            CharGroup group = nodeArray.mData.get(i);
             if (null != group.mBigrams) return true;
             if (hasBigramsInternal(group.mChildren)) return true;
         }
@@ -729,7 +730,7 @@ public final class FusionDictionary implements Iterable<Word> {
     // find a more efficient way of doing this, without compromising too much on memory
     // and ease of use.
     public boolean hasBigrams() {
-        return hasBigramsInternal(mRoot);
+        return hasBigramsInternal(mRootNodeArray);
     }
 
     // Historically, the tails of the words were going to be merged to save space.
@@ -750,13 +751,13 @@ public final class FusionDictionary implements Iterable<Word> {
 //        MakedictLog.i("Merging nodes. Number of nodes : " + countNodes(root));
 //        MakedictLog.i("Number of groups : " + countCharGroups(root));
 //
-//        final HashMap<String, ArrayList<Node>> repository =
-//                  new HashMap<String, ArrayList<Node>>();
+//        final HashMap<String, ArrayList<PtNodeArray>> repository =
+//                  new HashMap<String, ArrayList<PtNodeArray>>();
 //        mergeTailsInner(repository, root);
 //
 //        MakedictLog.i("Number of different pseudohashes : " + repository.size());
 //        int size = 0;
-//        for (ArrayList<Node> a : repository.values()) {
+//        for (ArrayList<PtNodeArray> a : repository.values()) {
 //            size += a.size();
 //        }
 //        MakedictLog.i("Number of nodes after merge : " + (1 + size));
@@ -764,7 +765,7 @@ public final class FusionDictionary implements Iterable<Word> {
     }
 
     // The following methods are used by the deactivated mergeTails()
-//   private static boolean isEqual(Node a, Node b) {
+//   private static boolean isEqual(PtNodeArray a, PtNodeArray b) {
 //       if (null == a && null == b) return true;
 //       if (null == a || null == b) return false;
 //       if (a.data.size() != b.data.size()) return false;
@@ -781,21 +782,21 @@ public final class FusionDictionary implements Iterable<Word> {
 //       return true;
 //   }
 
-//   static private HashMap<String, ArrayList<Node>> mergeTailsInner(
-//           final HashMap<String, ArrayList<Node>> map, final Node node) {
-//       final ArrayList<CharGroup> branches = node.data;
+//   static private HashMap<String, ArrayList<PtNodeArray>> mergeTailsInner(
+//           final HashMap<String, ArrayList<PtNodeArray>> map, final PtNodeArray nodeArray) {
+//       final ArrayList<CharGroup> branches = nodeArray.data;
 //       final int nodeSize = branches.size();
 //       for (int i = 0; i < nodeSize; ++i) {
 //           CharGroup group = branches.get(i);
 //           if (null != group.children) {
 //               String pseudoHash = getPseudoHash(group.children);
-//               ArrayList<Node> similarList = map.get(pseudoHash);
+//               ArrayList<PtNodeArray> similarList = map.get(pseudoHash);
 //               if (null == similarList) {
-//                   similarList = new ArrayList<Node>();
+//                   similarList = new ArrayList<PtNodeArray>();
 //                   map.put(pseudoHash, similarList);
 //               }
 //               boolean merged = false;
-//               for (Node similar : similarList) {
+//               for (PtNodeArray similar : similarList) {
 //                   if (isEqual(group.children, similar)) {
 //                       group.children = similar;
 //                       merged = true;
@@ -811,9 +812,9 @@ public final class FusionDictionary implements Iterable<Word> {
 //       return map;
 //   }
 
-//  private static String getPseudoHash(final Node node) {
+//  private static String getPseudoHash(final PtNodeArray nodeArray) {
 //      StringBuilder s = new StringBuilder();
-//      for (CharGroup g : node.data) {
+//      for (CharGroup g : nodeArray.data) {
 //          s.append(g.frequency);
 //          for (int ch : g.chars) {
 //              s.append(Character.toChars(ch));
@@ -901,6 +902,6 @@ public final class FusionDictionary implements Iterable<Word> {
      */
     @Override
     public Iterator<Word> iterator() {
-        return new DictionaryIterator(mRoot.mData);
+        return new DictionaryIterator(mRootNodeArray.mData);
     }
 }
diff --git a/java/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtils.java b/java/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtils.java
index aed07fd16..cd03b3822 100644
--- a/java/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtils.java
+++ b/java/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtils.java
@@ -25,7 +25,7 @@ import com.android.inputmethod.latin.makedict.BinaryDictIOUtils;
 import com.android.inputmethod.latin.makedict.BinaryDictReader;
 import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
 import com.android.inputmethod.latin.makedict.FusionDictionary;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.PendingAttribute;
 import com.android.inputmethod.latin.makedict.UnsupportedFormatException;
 import com.android.inputmethod.latin.personalization.UserHistoryDictionaryBigramList;
@@ -78,7 +78,7 @@ public final class UserHistoryDictIOUtils {
     @UsedForTesting
     static FusionDictionary constructFusionDictionary(
             final BigramDictionaryInterface dict, final UserHistoryDictionaryBigramList bigrams) {
-        final FusionDictionary fusionDict = new FusionDictionary(new Node(),
+        final FusionDictionary fusionDict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(new HashMap<String, String>(), false,
                         false));
         int profTotal = 0;
@@ -102,7 +102,7 @@ public final class UserHistoryDictIOUtils {
                 if (word1 == null) { // unigram
                     fusionDict.add(word2, freq, null, false /* isNotAWord */);
                 } else { // bigram
-                    if (FusionDictionary.findWordInTree(fusionDict.mRoot, word1) == null) {
+                    if (FusionDictionary.findWordInTree(fusionDict.mRootNodeArray, word1) == null) {
                         fusionDict.add(word1, 2, null, false /* isNotAWord */);
                     }
                     fusionDict.setBigram(word1, word2, freq);
diff --git a/tests/src/com/android/inputmethod/latin/FusionDictionaryTests.java b/tests/src/com/android/inputmethod/latin/FusionDictionaryTests.java
index 65dfd2dde..cadd0f8f3 100644
--- a/tests/src/com/android/inputmethod/latin/FusionDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/FusionDictionaryTests.java
@@ -20,7 +20,7 @@ import android.test.AndroidTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
 import com.android.inputmethod.latin.makedict.FusionDictionary;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 
 import java.util.HashMap;
 
@@ -30,21 +30,21 @@ import java.util.HashMap;
 @SmallTest
 public class FusionDictionaryTests extends AndroidTestCase {
     public void testFindWordInTree() {
-        FusionDictionary dict = new FusionDictionary(new Node(),
+        FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(new HashMap<String,String>(), false, false));
 
         dict.add("abc", 10, null, false /* isNotAWord */);
-        assertNull(FusionDictionary.findWordInTree(dict.mRoot, "aaa"));
-        assertNotNull(FusionDictionary.findWordInTree(dict.mRoot, "abc"));
+        assertNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "aaa"));
+        assertNotNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "abc"));
 
         dict.add("aa", 10, null, false /* isNotAWord */);
-        assertNull(FusionDictionary.findWordInTree(dict.mRoot, "aaa"));
-        assertNotNull(FusionDictionary.findWordInTree(dict.mRoot, "aa"));
+        assertNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "aaa"));
+        assertNotNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "aa"));
 
         dict.add("babcd", 10, null, false /* isNotAWord */);
         dict.add("bacde", 10, null, false /* isNotAWord */);
-        assertNull(FusionDictionary.findWordInTree(dict.mRoot, "ba"));
-        assertNotNull(FusionDictionary.findWordInTree(dict.mRoot, "babcd"));
-        assertNotNull(FusionDictionary.findWordInTree(dict.mRoot, "bacde"));
+        assertNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "ba"));
+        assertNotNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "babcd"));
+        assertNotNull(FusionDictionary.findWordInTree(dict.mRootNodeArray, "bacde"));
     }
 }
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
index 9664779f0..6d37466b7 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderEncoderTests.java
@@ -25,7 +25,7 @@ import android.util.SparseArray;
 import com.android.inputmethod.latin.makedict.BinaryDictDecoder.FusionDictionaryBufferInterface;
 import com.android.inputmethod.latin.makedict.FormatSpec.FileHeader;
 import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.utils.CollectionUtils;
 
@@ -226,7 +226,7 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
 
         // check unigram
         for (final String word : words) {
-            final CharGroup cg = FusionDictionary.findWordInTree(dict.mRoot, word);
+            final CharGroup cg = FusionDictionary.findWordInTree(dict.mRootNodeArray, word);
             assertNotNull(cg);
         }
 
@@ -234,7 +234,8 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
         for (int i = 0; i < bigrams.size(); ++i) {
             final int w1 = bigrams.keyAt(i);
             for (final int w2 : bigrams.valueAt(i)) {
-                final CharGroup cg = FusionDictionary.findWordInTree(dict.mRoot, words.get(w1));
+                final CharGroup cg = FusionDictionary.findWordInTree(dict.mRootNodeArray,
+                        words.get(w1));
                 assertNotNull(words.get(w1) + "," + words.get(w2), cg.getBigram(words.get(w2)));
             }
         }
@@ -242,7 +243,8 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
         // check shortcut
         if (shortcutMap != null) {
             for (final Map.Entry<String, List<String>> entry : shortcutMap.entrySet()) {
-                final CharGroup group = FusionDictionary.findWordInTree(dict.mRoot, entry.getKey());
+                final CharGroup group = FusionDictionary.findWordInTree(dict.mRootNodeArray,
+                        entry.getKey());
                 for (final String word : entry.getValue()) {
                     assertNotNull("shortcut not found: " + entry.getKey() + ", " + word,
                             group.getShortcut(word));
@@ -297,7 +299,7 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
         }
         assertNotNull(file);
 
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(new HashMap<String,String>(), false, false));
         addUnigrams(words.size(), dict, words, shortcuts);
         addBigrams(dict, words, bigrams);
@@ -440,7 +442,7 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
         assertNotNull(file);
 
         // making the dictionary from lists of words.
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(
                         new HashMap<String, String>(), false, false));
         addUnigrams(words.size(), dict, words, null /* shortcutMap */);
@@ -538,7 +540,7 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
         }
         assertNotNull(file);
 
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(
                         new HashMap<String, String>(), false, false));
         addUnigrams(sWords.size(), dict, sWords, null /* shortcutMap */);
@@ -599,7 +601,7 @@ public class BinaryDictDecoderEncoderTests extends AndroidTestCase {
         }
         assertNotNull(file);
 
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(
                         new HashMap<String, String>(), false, false));
         addUnigrams(sWords.size(), dict, sWords, null /* shortcutMap */);
diff --git a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java
index f2476b2e6..011d711de 100644
--- a/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java
+++ b/tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtilsTests.java
@@ -24,7 +24,7 @@ import android.util.Log;
 import com.android.inputmethod.latin.makedict.BinaryDictDecoder.ByteBufferWrapper;
 import com.android.inputmethod.latin.makedict.BinaryDictDecoder.FusionDictionaryBufferInterface;
 import com.android.inputmethod.latin.makedict.FormatSpec.FileHeader;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.utils.CollectionUtils;
 
@@ -277,7 +277,7 @@ public class BinaryDictIOUtilsTests extends AndroidTestCase {
         }
 
         // set an initial dictionary.
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(new HashMap<String,String>(), false, false));
         dict.add("abcd", 10, null, false);
 
@@ -328,7 +328,7 @@ public class BinaryDictIOUtilsTests extends AndroidTestCase {
         }
 
         // set an initial dictionary.
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(new HashMap<String,String>(), false, false));
         dict.add("abcd", 10, null, false);
         dict.add("efgh", 15, null, false);
@@ -365,7 +365,7 @@ public class BinaryDictIOUtilsTests extends AndroidTestCase {
         assertNotNull(file);
 
         // set an initial dictionary.
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new FusionDictionary.DictionaryOptions(new HashMap<String, String>(), false,
                         false));
         dict.add("initial", 10, null, false);
diff --git a/tests/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtilsTests.java b/tests/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtilsTests.java
index ce62bf21a..fd5517665 100644
--- a/tests/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtilsTests.java
+++ b/tests/src/com/android/inputmethod/latin/utils/UserHistoryDictIOUtilsTests.java
@@ -86,7 +86,7 @@ public class UserHistoryDictIOUtilsTests extends AndroidTestCase
 
     private void checkWordInFusionDict(final FusionDictionary dict, final String word,
             final ArrayList<String> expectedBigrams) {
-        final CharGroup group = FusionDictionary.findWordInTree(dict.mRoot, word);
+        final CharGroup group = FusionDictionary.findWordInTree(dict.mRootNodeArray, word);
         assertNotNull(group);
         assertTrue(group.isTerminal());
 
diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/CombinedInputOutput.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/CombinedInputOutput.java
index 092ee767f..4b6716936 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/CombinedInputOutput.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/CombinedInputOutput.java
@@ -19,7 +19,7 @@ package com.android.inputmethod.latin.dicttool;
 import com.android.inputmethod.latin.makedict.FormatSpec;
 import com.android.inputmethod.latin.makedict.FusionDictionary;
 import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.makedict.Word;
 
@@ -117,7 +117,7 @@ public class CombinedInputOutput {
         final boolean processLigatures =
                 FRENCH_LIGATURE_PROCESSING_OPTION.equals(attributes.get(OPTIONS_TAG));
         attributes.remove(OPTIONS_TAG);
-        final FusionDictionary dict = new FusionDictionary(new Node(), new DictionaryOptions(
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(), new DictionaryOptions(
                 attributes, processUmlauts, processLigatures));
 
         String line;
diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Diff.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Diff.java
index 5c3e87e10..d790d0652 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Diff.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Diff.java
@@ -121,7 +121,8 @@ public class Diff extends Dicttool.Command {
     private static void diffWords(final FusionDictionary dict0, final FusionDictionary dict1) {
         boolean hasDifferences = false;
         for (final Word word0 : dict0) {
-            final CharGroup word1 = FusionDictionary.findWordInTree(dict1.mRoot, word0.mWord);
+            final CharGroup word1 = FusionDictionary.findWordInTree(dict1.mRootNodeArray,
+                    word0.mWord);
             if (null == word1) {
                 // This word is not in dict1
                 System.out.println("Deleted: " + word0.mWord + " " + word0.mFrequency);
@@ -150,7 +151,8 @@ public class Diff extends Dicttool.Command {
             }
         }
         for (final Word word1 : dict1) {
-            final CharGroup word0 = FusionDictionary.findWordInTree(dict0.mRoot, word1.mWord);
+            final CharGroup word0 = FusionDictionary.findWordInTree(dict0.mRootNodeArray,
+                    word1.mWord);
             if (null == word0) {
                 // This word is not in dict0
                 System.out.println("Added: " + word1.mWord + " " + word1.mFrequency);
diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Info.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Info.java
index f2894544f..fa8c5f776 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Info.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/Info.java
@@ -65,7 +65,7 @@ public class Info extends Dicttool.Command {
 
     private static void showWordInfo(final FusionDictionary dict, final String word,
             final boolean plumbing) {
-        final CharGroup group = FusionDictionary.findWordInTree(dict.mRoot, word);
+        final CharGroup group = FusionDictionary.findWordInTree(dict.mRootNodeArray, word);
         if (null == group) {
             System.out.println(word + " is not in the dictionary");
             return;
diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/XmlDictInputOutput.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/XmlDictInputOutput.java
index 1fd2cba7a..4e99bf979 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/XmlDictInputOutput.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/XmlDictInputOutput.java
@@ -18,7 +18,7 @@ package com.android.inputmethod.latin.dicttool;
 
 import com.android.inputmethod.latin.makedict.FusionDictionary;
 import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 import com.android.inputmethod.latin.makedict.Word;
 
@@ -124,8 +124,8 @@ public class XmlDictInputOutput {
                         GERMAN_UMLAUT_PROCESSING_OPTION.equals(optionsString);
                 final boolean processLigatures =
                         FRENCH_LIGATURE_PROCESSING_OPTION.equals(optionsString);
-                mDictionary = new FusionDictionary(new Node(), new DictionaryOptions(attributes,
-                        processUmlauts, processLigatures));
+                mDictionary = new FusionDictionary(new PtNodeArray(),
+                        new DictionaryOptions(attributes, processUmlauts, processLigatures));
             } else {
                 mState = UNKNOWN;
             }
diff --git a/tools/dicttool/tests/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtilsTests.java b/tools/dicttool/tests/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtilsTests.java
index 01fadfc82..3bda77fe9 100644
--- a/tools/dicttool/tests/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtilsTests.java
+++ b/tools/dicttool/tests/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtilsTests.java
@@ -22,7 +22,7 @@ import com.android.inputmethod.latin.makedict.BinaryDictReader;
 import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
 import com.android.inputmethod.latin.makedict.FusionDictionary;
 import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.UnsupportedFormatException;
 
 import junit.framework.TestCase;
@@ -42,7 +42,7 @@ public class BinaryDictOffdeviceUtilsTests extends TestCase {
 
     public void testGetRawDictWorks() throws IOException, UnsupportedFormatException {
         // Create a thrice-compressed dictionary file.
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new DictionaryOptions(new HashMap<String, String>(),
                         false /* germanUmlautProcessing */, false /* frenchLigatureProcessing */));
         dict.add("foo", TEST_FREQ, null, false /* isNotAWord */);
@@ -72,7 +72,8 @@ public class BinaryDictOffdeviceUtilsTests extends TestCase {
         final FusionDictionary resultDict = BinaryDictDecoder.readDictionaryBinary(reader,
                 null /* dict : an optional dictionary to add words to, or null */);
         assertEquals("Dictionary can't be read back correctly",
-                FusionDictionary.findWordInTree(resultDict.mRoot, "foo").getFrequency(), TEST_FREQ);
+                FusionDictionary.findWordInTree(resultDict.mRootNodeArray, "foo").getFrequency(),
+                TEST_FREQ);
     }
 
     public void testGetRawDictFails() throws IOException {
diff --git a/tools/dicttool/tests/com/android/inputmethod/latin/makedict/BinaryDictEncoderFlattenTreeTests.java b/tools/dicttool/tests/com/android/inputmethod/latin/makedict/BinaryDictEncoderFlattenTreeTests.java
index 2fcfb5e15..fe6738303 100644
--- a/tools/dicttool/tests/com/android/inputmethod/latin/makedict/BinaryDictEncoderFlattenTreeTests.java
+++ b/tools/dicttool/tests/com/android/inputmethod/latin/makedict/BinaryDictEncoderFlattenTreeTests.java
@@ -17,7 +17,7 @@
 package com.android.inputmethod.latin.makedict;
 
 import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 
 import junit.framework.TestCase;
 
@@ -31,7 +31,7 @@ public class BinaryDictEncoderFlattenTreeTests extends TestCase {
     // Test the flattened array contains the expected number of nodes, and
     // that it does not contain any duplicates.
     public void testFlattenNodes() {
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new DictionaryOptions(new HashMap<String, String>(),
                         false /* germanUmlautProcessing */, false /* frenchLigatureProcessing */));
         dict.add("foo", 1, null, false /* isNotAWord */);
@@ -39,10 +39,10 @@ public class BinaryDictEncoderFlattenTreeTests extends TestCase {
         dict.add("ftb", 1, null, false /* isNotAWord */);
         dict.add("bar", 1, null, false /* isNotAWord */);
         dict.add("fool", 1, null, false /* isNotAWord */);
-        final ArrayList<Node> result = BinaryDictEncoder.flattenTree(dict.mRoot);
+        final ArrayList<PtNodeArray> result = BinaryDictEncoder.flattenTree(dict.mRootNodeArray);
         assertEquals(4, result.size());
         while (!result.isEmpty()) {
-            final Node n = result.remove(0);
+            final PtNodeArray n = result.remove(0);
             assertFalse("Flattened array contained the same node twice", result.contains(n));
         }
     }
diff --git a/tools/dicttool/tests/com/android/inputmethod/latin/makedict/FusionDictionaryTest.java b/tools/dicttool/tests/com/android/inputmethod/latin/makedict/FusionDictionaryTest.java
index 8efb4a4b9..22c0ceb4c 100644
--- a/tools/dicttool/tests/com/android/inputmethod/latin/makedict/FusionDictionaryTest.java
+++ b/tools/dicttool/tests/com/android/inputmethod/latin/makedict/FusionDictionaryTest.java
@@ -19,7 +19,7 @@ package com.android.inputmethod.latin.makedict;
 import com.android.inputmethod.latin.makedict.FusionDictionary;
 import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
 import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
+import com.android.inputmethod.latin.makedict.FusionDictionary.PtNodeArray;
 import com.android.inputmethod.latin.makedict.Word;
 
 import junit.framework.TestCase;
@@ -72,7 +72,7 @@ public class FusionDictionaryTest extends TestCase {
         assertNotNull(dict);
         for (final String word : words) {
             if (--limit < 0) return;
-            final CharGroup cg = FusionDictionary.findWordInTree(dict.mRoot, word);
+            final CharGroup cg = FusionDictionary.findWordInTree(dict.mRootNodeArray, word);
             assertNotNull(cg);
         }
     }
@@ -95,7 +95,7 @@ public class FusionDictionaryTest extends TestCase {
     // Test the flattened array contains the expected number of nodes, and
     // that it does not contain any duplicates.
     public void testFusion() {
-        final FusionDictionary dict = new FusionDictionary(new Node(),
+        final FusionDictionary dict = new FusionDictionary(new PtNodeArray(),
                 new DictionaryOptions(new HashMap<String, String>(),
                         false /* germanUmlautProcessing */, false /* frenchLigatureProcessing */));
         final long time = System.currentTimeMillis();