1/*
2 * Copyright (C) 2012 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.personalization;
18
19import android.util.Log;
20
21import com.android.inputmethod.annotations.UsedForTesting;
22import com.android.inputmethod.latin.utils.CollectionUtils;
23
24import java.util.HashMap;
25import java.util.Set;
26
27/**
28 * A store of bigrams which will be updated when the user history dictionary is closed
29 * All bigrams including stale ones in SQL DB should be stored in this class to avoid adding stale
30 * bigrams when we write to the SQL DB.
31 */
32@UsedForTesting
33public final class UserHistoryDictionaryBigramList {
34    public static final byte FORGETTING_CURVE_INITIAL_VALUE = 0;
35    private static final String TAG = UserHistoryDictionaryBigramList.class.getSimpleName();
36    private static final HashMap<String, Byte> EMPTY_BIGRAM_MAP = CollectionUtils.newHashMap();
37    private final HashMap<String, HashMap<String, Byte>> mBigramMap = CollectionUtils.newHashMap();
38    private int mSize = 0;
39
40    public void evictAll() {
41        mSize = 0;
42        mBigramMap.clear();
43    }
44
45    /**
46     * Called when the user typed a word.
47     */
48    @UsedForTesting
49    public void addBigram(String word1, String word2) {
50        addBigram(word1, word2, FORGETTING_CURVE_INITIAL_VALUE);
51    }
52
53    /**
54     * Called when loaded from the SQL DB.
55     */
56    public void addBigram(String word1, String word2, byte fcValue) {
57        if (DecayingExpandableBinaryDictionaryBase.DBG_SAVE_RESTORE) {
58            Log.d(TAG, "--- add bigram: " + word1 + ", " + word2 + ", " + fcValue);
59        }
60        final HashMap<String, Byte> map;
61        if (mBigramMap.containsKey(word1)) {
62            map = mBigramMap.get(word1);
63        } else {
64            map = CollectionUtils.newHashMap();
65            mBigramMap.put(word1, map);
66        }
67        if (!map.containsKey(word2)) {
68            ++mSize;
69            map.put(word2, fcValue);
70        }
71    }
72
73    /**
74     * Called when inserted to the SQL DB.
75     */
76    public void updateBigram(String word1, String word2, byte fcValue) {
77        if (DecayingExpandableBinaryDictionaryBase.DBG_SAVE_RESTORE) {
78            Log.d(TAG, "--- update bigram: " + word1 + ", " + word2 + ", " + fcValue);
79        }
80        final HashMap<String, Byte> map;
81        if (mBigramMap.containsKey(word1)) {
82            map = mBigramMap.get(word1);
83        } else {
84            return;
85        }
86        if (!map.containsKey(word2)) {
87            return;
88        }
89        map.put(word2, fcValue);
90    }
91
92    public int size() {
93        return mSize;
94    }
95
96    public boolean isEmpty() {
97        return mBigramMap.isEmpty();
98    }
99
100    public boolean containsKey(String word) {
101        return mBigramMap.containsKey(word);
102    }
103
104    public Set<String> keySet() {
105        return mBigramMap.keySet();
106    }
107
108    public HashMap<String, Byte> getBigrams(String word1) {
109        if (mBigramMap.containsKey(word1)) return mBigramMap.get(word1);
110        // TODO: lower case according to locale
111        final String lowerWord1 = word1.toLowerCase();
112        if (mBigramMap.containsKey(lowerWord1)) return mBigramMap.get(lowerWord1);
113        return EMPTY_BIGRAM_MAP;
114    }
115
116    public boolean removeBigram(String word1, String word2) {
117        final HashMap<String, Byte> set = getBigrams(word1);
118        if (set.isEmpty()) {
119            return false;
120        }
121        if (set.containsKey(word2)) {
122            set.remove(word2);
123            --mSize;
124            return true;
125        }
126        return false;
127    }
128}
129