Create DictionaryFacilitatorLruCache.

This class is separated from AndroidSpellCheckerService

Bug: 16547557

Change-Id: I3e58521207395588cecb2977234b89067d6da8c3

1 files changed, 156 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/DictionaryFacilitatorLruCache.java b/java/src/com/android/inputmethod/latin/DictionaryFacilitatorLruCache.java
new file mode 100644
index 000000000..fa0265d86
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/DictionaryFacilitatorLruCache.java
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2014 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.latin;
+
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.concurrent.TimeUnit;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+
+import android.content.Context;
+import android.util.Log;
+import android.util.LruCache;
+
+/**
+ * Cache for dictionary facilitators of multiple locales.
+ * This class automatically creates and releases facilitator instances using LRU policy.
+ */
+public class DictionaryFacilitatorLruCache {
+    private static final String TAG = DictionaryFacilitatorLruCache.class.getSimpleName();
+    private static final int WAIT_FOR_LOADING_MAIN_DICT_IN_MILLISECONDS = 1000;
+    private static final int MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT = 5;
+
+    /**
+     * Class extends LruCache. This class tracks cached locales and closes evicted dictionaries by
+     * overriding entryRemoved.
+     */
+    private static class DictionaryFacilitatorLruCacheInner extends
+            LruCache<Locale, DictionaryFacilitator> {
+        private final HashSet<Locale> mCachedLocales;
+        public DictionaryFacilitatorLruCacheInner(final HashSet<Locale> cachedLocales,
+                final int maxSize) {
+            super(maxSize);
+            mCachedLocales = cachedLocales;
+        }
+
+        @Override
+        protected void entryRemoved(boolean evicted, Locale key,
+                DictionaryFacilitator oldValue, DictionaryFacilitator newValue) {
+            if (oldValue != null && oldValue != newValue) {
+                oldValue.closeDictionaries();
+            }
+            if (key != null && newValue == null) {
+                // Remove locale from the cache when the dictionary facilitator for the locale is
+                // evicted and new facilitator is not set for the locale.
+                mCachedLocales.remove(key);
+                if (size() >= maxSize()) {
+                    Log.w(TAG, "DictionaryFacilitator for " + key.toString()
+                            + " has been evicted due to cache size limit."
+                            + " size: " + size() + ", maxSize: " + maxSize());
+                }
+            }
+        }
+    }
+
+    private final Context mContext;
+    private final HashSet<Locale> mCachedLocales = new HashSet<>();
+    private final String mDictionaryNamePrefix;
+    private final DictionaryFacilitatorLruCacheInner mLruCache;
+    private final Object mLock = new Object();
+    private boolean mUseContactsDictionary = false;
+
+    public DictionaryFacilitatorLruCache(final Context context, final int maxSize,
+            final String dictionaryNamePrefix) {
+        mContext = context;
+        mLruCache = new DictionaryFacilitatorLruCacheInner(mCachedLocales, maxSize);
+        mDictionaryNamePrefix = dictionaryNamePrefix;
+    }
+
+    private void waitForLoadingMainDictionary(final DictionaryFacilitator dictionaryFacilitator) {
+        for (int i = 0; i < MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT; i++) {
+            try {
+                dictionaryFacilitator.waitForLoadingMainDictionary(
+                        WAIT_FOR_LOADING_MAIN_DICT_IN_MILLISECONDS, TimeUnit.MILLISECONDS);
+                return;
+            } catch (final InterruptedException e) {
+                Log.i(TAG, "Interrupted during waiting for loading main dictionary.", e);
+                if (i < MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT - 1) {
+                    Log.i(TAG, "Retry", e);
+                } else {
+                    Log.w(TAG, "Give up retrying. Retried "
+                            + MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT + " times.", e);
+                }
+            }
+        }
+    }
+
+    private void resetDictionariesForLocaleLocked(final DictionaryFacilitator dictionaryFacilitator,
+            final Locale locale) {
+        dictionaryFacilitator.resetDictionariesWithDictNamePrefix(mContext, locale,
+                mUseContactsDictionary, false /* usePersonalizedDicts */,
+                false /* forceReloadMainDictionary */, null /* listener */,
+                mDictionaryNamePrefix);
+    }
+
+    public void setUseContactsDictionary(final boolean useContectsDictionary) {
+        if (mUseContactsDictionary == useContectsDictionary) {
+            // The value has not been changed.
+            return;
+        }
+        synchronized (mLock) {
+            mUseContactsDictionary = useContectsDictionary;
+            for (final Locale locale : mCachedLocales) {
+                final DictionaryFacilitator dictionaryFacilitator = mLruCache.get(locale);
+                resetDictionariesForLocaleLocked(dictionaryFacilitator, locale);
+                waitForLoadingMainDictionary(dictionaryFacilitator);
+            }
+        }
+    }
+
+    public DictionaryFacilitator get(final Locale locale) {
+        DictionaryFacilitator dictionaryFacilitator = mLruCache.get(locale);
+        if (dictionaryFacilitator != null) {
+            // dictionary falicitator for the locale is in the cache.
+            return dictionaryFacilitator;
+        }
+        synchronized (mLock) {
+            dictionaryFacilitator = mLruCache.get(locale);
+            if (dictionaryFacilitator != null) {
+                return dictionaryFacilitator;
+            }
+            dictionaryFacilitator = new DictionaryFacilitator();
+            resetDictionariesForLocaleLocked(dictionaryFacilitator, locale);
+            waitForLoadingMainDictionary(dictionaryFacilitator);
+            mLruCache.put(locale, dictionaryFacilitator);
+            mCachedLocales.add(locale);
+            return dictionaryFacilitator;
+        }
+    }
+
+    public void evictAll() {
+        synchronized (mLock) {
+            mLruCache.evictAll();
+            mCachedLocales.clear();
+        }
+    }
+
+    @UsedForTesting
+    HashSet<Locale> getCachedLocalesForTesting() {
+        return mCachedLocales;
+    }
+}