1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.inputmethod.latin;
18
19import java.util.Locale;
20import java.util.concurrent.TimeUnit;
21
22import android.content.Context;
23import android.util.Log;
24
25/**
26 * Cache for dictionary facilitators of multiple locales.
27 * This class automatically creates and releases up to 3 facilitator instances using LRU policy.
28 */
29public class DictionaryFacilitatorLruCache {
30    private static final String TAG = "DictionaryFacilitatorLruCache";
31    private static final int WAIT_FOR_LOADING_MAIN_DICT_IN_MILLISECONDS = 1000;
32    private static final int MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT = 5;
33
34    private final Context mContext;
35    private final String mDictionaryNamePrefix;
36    private final Object mLock = new Object();
37    private final DictionaryFacilitator mDictionaryFacilitator;
38    private boolean mUseContactsDictionary;
39    private Locale mLocale;
40
41    public DictionaryFacilitatorLruCache(final Context context, final String dictionaryNamePrefix) {
42        mContext = context;
43        mDictionaryNamePrefix = dictionaryNamePrefix;
44        mDictionaryFacilitator = DictionaryFacilitatorProvider.getDictionaryFacilitator(
45                true /* isNeededForSpellChecking */);
46    }
47
48    private static void waitForLoadingMainDictionary(
49            final DictionaryFacilitator dictionaryFacilitator) {
50        for (int i = 0; i < MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT; i++) {
51            try {
52                dictionaryFacilitator.waitForLoadingMainDictionaries(
53                        WAIT_FOR_LOADING_MAIN_DICT_IN_MILLISECONDS, TimeUnit.MILLISECONDS);
54                return;
55            } catch (final InterruptedException e) {
56                Log.i(TAG, "Interrupted during waiting for loading main dictionary.", e);
57                if (i < MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT - 1) {
58                    Log.i(TAG, "Retry", e);
59                } else {
60                    Log.w(TAG, "Give up retrying. Retried "
61                            + MAX_RETRY_COUNT_FOR_WAITING_FOR_LOADING_DICT + " times.", e);
62                }
63            }
64        }
65    }
66
67    private void resetDictionariesForLocaleLocked() {
68        // Nothing to do if the locale is null.  This would be the case before any get() calls.
69        if (mLocale != null) {
70          // Note: Given that personalized dictionaries are not used here; we can pass null account.
71          mDictionaryFacilitator.resetDictionaries(mContext, mLocale,
72              mUseContactsDictionary, false /* usePersonalizedDicts */,
73              false /* forceReloadMainDictionary */, null /* account */,
74              mDictionaryNamePrefix, null /* listener */);
75        }
76    }
77
78    public void setUseContactsDictionary(final boolean useContactsDictionary) {
79        synchronized (mLock) {
80            if (mUseContactsDictionary == useContactsDictionary) {
81                // The value has not been changed.
82                return;
83            }
84            mUseContactsDictionary = useContactsDictionary;
85            resetDictionariesForLocaleLocked();
86            waitForLoadingMainDictionary(mDictionaryFacilitator);
87        }
88    }
89
90    public DictionaryFacilitator get(final Locale locale) {
91        synchronized (mLock) {
92            if (!mDictionaryFacilitator.isForLocale(locale)) {
93                mLocale = locale;
94                resetDictionariesForLocaleLocked();
95            }
96            waitForLoadingMainDictionary(mDictionaryFacilitator);
97            return mDictionaryFacilitator;
98        }
99    }
100
101    public void closeDictionaries() {
102        synchronized (mLock) {
103            mDictionaryFacilitator.closeDictionaries();
104        }
105    }
106}
107