1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 5 * use this file except in compliance with the License. You may obtain a copy of 6 * 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, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations under 14 * the License. 15 */ 16 17 package com.android.inputmethod.latin; 18 19 import com.android.inputmethod.keyboard.ProximityInfo; 20 21 /** 22 * Abstract base class for a dictionary that can do a fuzzy search for words based on a set of key 23 * strokes. 24 */ 25 public abstract class Dictionary { 26 /** 27 * The weight to give to a word if it's length is the same as the number of typed characters. 28 */ 29 protected static final int FULL_WORD_SCORE_MULTIPLIER = 2; 30 31 public static final int UNIGRAM = 0; 32 public static final int BIGRAM = 1; 33 34 public static final int NOT_A_PROBABILITY = -1; 35 /** 36 * Interface to be implemented by classes requesting words to be fetched from the dictionary. 37 * @see #getWords(WordComposer, CharSequence, WordCallback, ProximityInfo) 38 */ 39 public interface WordCallback { 40 /** 41 * Adds a word to a list of suggestions. The word is expected to be ordered based on 42 * the provided score. 43 * @param word the character array containing the word 44 * @param wordOffset starting offset of the word in the character array 45 * @param wordLength length of valid characters in the character array 46 * @param score the score of occurrence. This is normalized between 1 and 255, but 47 * can exceed those limits 48 * @param dicTypeId of the dictionary where word was from 49 * @param dataType tells type of this data, either UNIGRAM or BIGRAM 50 * @return true if the word was added, false if no more words are required 51 */ addWord(char[] word, int wordOffset, int wordLength, int score, int dicTypeId, int dataType)52 boolean addWord(char[] word, int wordOffset, int wordLength, int score, int dicTypeId, 53 int dataType); 54 } 55 56 /** 57 * Searches for words in the dictionary that match the characters in the composer. Matched 58 * words are added through the callback object. 59 * @param composer the key sequence to match 60 * @param prevWordForBigrams the previous word, or null if none 61 * @param callback the callback object to send matched words to as possible candidates 62 * @param proximityInfo the object for key proximity. May be ignored by some implementations. 63 * @see WordCallback#addWord(char[], int, int, int, int, int) 64 */ getWords(final WordComposer composer, final CharSequence prevWordForBigrams, final WordCallback callback, final ProximityInfo proximityInfo)65 abstract public void getWords(final WordComposer composer, 66 final CharSequence prevWordForBigrams, final WordCallback callback, 67 final ProximityInfo proximityInfo); 68 69 /** 70 * Searches for pairs in the bigram dictionary that matches the previous word and all the 71 * possible words following are added through the callback object. 72 * @param composer the key sequence to match 73 * @param previousWord the word before 74 * @param callback the callback object to send possible word following previous word 75 */ getBigrams(final WordComposer composer, final CharSequence previousWord, final WordCallback callback)76 public void getBigrams(final WordComposer composer, final CharSequence previousWord, 77 final WordCallback callback) { 78 // empty base implementation 79 } 80 81 /** 82 * Checks if the given word occurs in the dictionary 83 * @param word the word to search for. The search should be case-insensitive. 84 * @return true if the word exists, false otherwise 85 */ isValidWord(CharSequence word)86 abstract public boolean isValidWord(CharSequence word); 87 getFrequency(CharSequence word)88 public int getFrequency(CharSequence word) { 89 return NOT_A_PROBABILITY; 90 } 91 92 /** 93 * Compares the contents of the character array with the typed word and returns true if they 94 * are the same. 95 * @param word the array of characters that make up the word 96 * @param length the number of valid characters in the character array 97 * @param typedWord the word to compare with 98 * @return true if they are the same, false otherwise. 99 */ same(final char[] word, final int length, final CharSequence typedWord)100 protected boolean same(final char[] word, final int length, final CharSequence typedWord) { 101 if (typedWord.length() != length) { 102 return false; 103 } 104 for (int i = 0; i < length; i++) { 105 if (word[i] != typedWord.charAt(i)) { 106 return false; 107 } 108 } 109 return true; 110 } 111 112 /** 113 * Override to clean up any resources. 114 */ close()115 public void close() { 116 // empty base implementation 117 } 118 } 119