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