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 
17 package com.android.inputmethod.latin;
18 
19 import java.util.Locale;
20 import java.util.concurrent.TimeUnit;
21 
22 import android.content.Context;
23 import 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  */
29 public 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 
DictionaryFacilitatorLruCache(final Context context, final String dictionaryNamePrefix)41     public DictionaryFacilitatorLruCache(final Context context, final String dictionaryNamePrefix) {
42         mContext = context;
43         mDictionaryNamePrefix = dictionaryNamePrefix;
44         mDictionaryFacilitator = DictionaryFacilitatorProvider.getDictionaryFacilitator(
45                 true /* isNeededForSpellChecking */);
46     }
47 
waitForLoadingMainDictionary( final DictionaryFacilitator dictionaryFacilitator)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 
resetDictionariesForLocaleLocked()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 
setUseContactsDictionary(final boolean useContactsDictionary)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 
get(final Locale locale)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 
closeDictionaries()101     public void closeDictionaries() {
102         synchronized (mLock) {
103             mDictionaryFacilitator.closeDictionaries();
104         }
105     }
106 }
107