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 * Whether or not to replicate the typed word in the suggested list, even if it's valid. 28 */ 29 protected static final boolean INCLUDE_TYPED_WORD_IF_VALID = false; 30 31 /** 32 * The weight to give to a word if it's length is the same as the number of typed characters. 33 */ 34 protected static final int FULL_WORD_SCORE_MULTIPLIER = 2; 35 36 public static enum DataType { 37 UNIGRAM, BIGRAM 38 } 39 40 /** 41 * Interface to be implemented by classes requesting words to be fetched from the dictionary. 42 * @see #getWords(WordComposer, WordCallback) 43 */ 44 public interface WordCallback { 45 /** 46 * Adds a word to a list of suggestions. The word is expected to be ordered based on 47 * the provided score. 48 * @param word the character array containing the word 49 * @param wordOffset starting offset of the word in the character array 50 * @param wordLength length of valid characters in the character array 51 * @param score the score of occurrence. This is normalized between 1 and 255, but 52 * can exceed those limits 53 * @param dicTypeId of the dictionary where word was from 54 * @param dataType tells type of this data 55 * @return true if the word was added, false if no more words are required 56 */ addWord(char[] word, int wordOffset, int wordLength, int score, int dicTypeId, DataType dataType)57 boolean addWord(char[] word, int wordOffset, int wordLength, int score, int dicTypeId, 58 DataType dataType); 59 } 60 61 /** 62 * Searches for words in the dictionary that match the characters in the composer. Matched 63 * words are added through the callback object. 64 * @param composer the key sequence to match 65 * @param callback the callback object to send matched words to as possible candidates 66 * @param proximityInfo the object for key proximity. May be ignored by some implementations. 67 * @see WordCallback#addWord(char[], int, int, int, int, DataType) 68 */ getWords(final WordComposer composer, final WordCallback callback, final ProximityInfo proximityInfo)69 abstract public void getWords(final WordComposer composer, final WordCallback callback, 70 final ProximityInfo proximityInfo); 71 72 /** 73 * Searches for pairs in the bigram dictionary that matches the previous word and all the 74 * possible words following are added through the callback object. 75 * @param composer the key sequence to match 76 * @param previousWord the word before 77 * @param callback the callback object to send possible word following previous word 78 */ getBigrams(final WordComposer composer, final CharSequence previousWord, final WordCallback callback)79 public void getBigrams(final WordComposer composer, final CharSequence previousWord, 80 final WordCallback callback) { 81 // empty base implementation 82 } 83 84 /** 85 * Checks if the given word occurs in the dictionary 86 * @param word the word to search for. The search should be case-insensitive. 87 * @return true if the word exists, false otherwise 88 */ isValidWord(CharSequence word)89 abstract public boolean isValidWord(CharSequence word); 90 91 /** 92 * Compares the contents of the character array with the typed word and returns true if they 93 * are the same. 94 * @param word the array of characters that make up the word 95 * @param length the number of valid characters in the character array 96 * @param typedWord the word to compare with 97 * @return true if they are the same, false otherwise. 98 */ same(final char[] word, final int length, final CharSequence typedWord)99 protected boolean same(final char[] word, final int length, final CharSequence typedWord) { 100 if (typedWord.length() != length) { 101 return false; 102 } 103 for (int i = 0; i < length; i++) { 104 if (word[i] != typedWord.charAt(i)) { 105 return false; 106 } 107 } 108 return true; 109 } 110 111 /** 112 * Override to clean up any resources. 113 */ close()114 public void close() { 115 // empty base implementation 116 } 117 } 118