Add ArraysCompatUtils.binarySearch

Until API version 9, java.util.Arrays.binarySearch(int[], int, int,
int) doesn't exist.

Change-Id: Ife0ed4fbac642eda069e7b6f6b8dd30e0cd5fdee

2 files changed, 53 insertions, 2 deletions

diff --git a/java/src/com/android/inputmethod/compat/ArraysCompatUtils.java b/java/src/com/android/inputmethod/compat/ArraysCompatUtils.java
new file mode 100644
index 000000000..f6afbcfe2
--- /dev/null
+++ b/java/src/com/android/inputmethod/compat/ArraysCompatUtils.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.compat;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+
+public class ArraysCompatUtils {
+    private static final Method METHOD_Arrays_binarySearch = CompatUtils
+            .getMethod(Arrays.class, "binarySearch", int[].class, int.class, int.class, int.class);
+
+    public static int binarySearch(int[] array, int startIndex, int endIndex, int value) {
+        if (METHOD_Arrays_binarySearch != null) {
+            final Object index = CompatUtils.invoke(null, 0, METHOD_Arrays_binarySearch,
+                    array, startIndex, endIndex, value);
+            return (Integer)index;
+        } else {
+            return compatBinarySearch(array, startIndex, endIndex, value);
+        }
+    }
+
+    /* package */ static int compatBinarySearch(int[] array, int startIndex, int endIndex,
+            int value) {
+        if (startIndex > endIndex) throw new IllegalArgumentException();
+        if (startIndex < 0 || endIndex > array.length) throw new ArrayIndexOutOfBoundsException();
+
+        final int work[] = new int[endIndex - startIndex];
+        System.arraycopy(array, startIndex, work, 0, work.length);
+        final int index = Arrays.binarySearch(work, value);
+        if (index >= 0) {
+            return index + startIndex;
+        } else {
+            return ~(~index + startIndex);
+        }
+    }
+}
diff --git a/java/src/com/android/inputmethod/latin/spellcheck/SpellChecker.java b/java/src/com/android/inputmethod/latin/spellcheck/SpellChecker.java
index e3407a269..63c6d69d7 100644
--- a/java/src/com/android/inputmethod/latin/spellcheck/SpellChecker.java
+++ b/java/src/com/android/inputmethod/latin/spellcheck/SpellChecker.java
@@ -19,6 +19,7 @@ package com.android.inputmethod.latin.spellcheck;
 import android.content.Context;
 import android.content.res.Resources;
 
+import com.android.inputmethod.compat.ArraysCompatUtils;
 import com.android.inputmethod.latin.Dictionary;
 import com.android.inputmethod.latin.Dictionary.DataType;
 import com.android.inputmethod.latin.Dictionary.WordCallback;
@@ -26,7 +27,6 @@ import com.android.inputmethod.latin.DictionaryFactory;
 import com.android.inputmethod.latin.Utils;
 import com.android.inputmethod.latin.WordComposer;
 
-import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
@@ -64,13 +64,14 @@ public class SpellChecker {
         private int[] mScores = new int[DEFAULT_SUGGESTION_LENGTH];
         private int mLength = 0;
 
+        @Override
         synchronized public boolean addWord(char[] word, int wordOffset, int wordLength, int score,
                 int dicTypeId, DataType dataType) {
             if (mLength >= mScores.length) {
                 final int newLength = mScores.length * 2;
                 mScores = new int[newLength];
             }
-            final int positionIndex = Arrays.binarySearch(mScores, 0, mLength, score);
+            final int positionIndex = ArraysCompatUtils.binarySearch(mScores, 0, mLength, score);
             // binarySearch returns the index if the element exists, and -<insertion index> - 1
             // if it doesn't. See documentation for binarySearch.
             final int insertionIndex = positionIndex >= 0 ? positionIndex : -positionIndex - 1;