LatinIME/java/src/com/android/inputmethod/latin/Dictionary.java

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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.android.inputmethod.latin;
import com.android.inputmethod.keyboard.ProximityInfo;
/**
* Abstract base class for a dictionary that can do a fuzzy search for words based on a set of key
* strokes.
*/
public abstract class Dictionary {
/**
* The weight to give to a word if it's length is the same as the number of typed characters.
*/
protected static final int FULL_WORD_SCORE_MULTIPLIER = 2;
public static final int UNIGRAM = 0;
public static final int BIGRAM = 1;
public static final int NOT_A_PROBABILITY = -1;
/**
* Interface to be implemented by classes requesting words to be fetched from the dictionary.
* @see #getWords(WordComposer, CharSequence, WordCallback, ProximityInfo)
*/
public interface WordCallback {
/**
* Adds a word to a list of suggestions. The word is expected to be ordered based on
* the provided score.
* @param word the character array containing the word
* @param wordOffset starting offset of the word in the character array
* @param wordLength length of valid characters in the character array
* @param score the score of occurrence. This is normalized between 1 and 255, but
* can exceed those limits
* @param dicTypeId of the dictionary where word was from
* @param dataType tells type of this data, either UNIGRAM or BIGRAM
* @return true if the word was added, false if no more words are required
*/
boolean addWord(char[] word, int wordOffset, int wordLength, int score, int dicTypeId,
int dataType);
}
/**
* Searches for words in the dictionary that match the characters in the composer. Matched
* words are added through the callback object.
* @param composer the key sequence to match
* @param prevWordForBigrams the previous word, or null if none
* @param callback the callback object to send matched words to as possible candidates
* @param proximityInfo the object for key proximity. May be ignored by some implementations.
* @see WordCallback#addWord(char[], int, int, int, int, int)
*/
abstract public void getWords(final WordComposer composer,
final CharSequence prevWordForBigrams, final WordCallback callback,
final ProximityInfo proximityInfo);
/**
* Searches for pairs in the bigram dictionary that matches the previous word and all the
* possible words following are added through the callback object.
* @param composer the key sequence to match
* @param previousWord the word before
* @param callback the callback object to send possible word following previous word
*/
public void getBigrams(final WordComposer composer, final CharSequence previousWord,
final WordCallback callback) {
// empty base implementation
}
/**
* Checks if the given word occurs in the dictionary
* @param word the word to search for. The search should be case-insensitive.
* @return true if the word exists, false otherwise
*/
abstract public boolean isValidWord(CharSequence word);
public int getFrequency(CharSequence word) {
return NOT_A_PROBABILITY;
}
/**
* Compares the contents of the character array with the typed word and returns true if they
* are the same.
* @param word the array of characters that make up the word
* @param length the number of valid characters in the character array
* @param typedWord the word to compare with
* @return true if they are the same, false otherwise.
*/
protected boolean same(final char[] word, final int length, final CharSequence typedWord) {
if (typedWord.length() != length) {
return false;
}
for (int i = 0; i < length; i++) {
if (word[i] != typedWord.charAt(i)) {
return false;
}
}
return true;
}
/**
* Override to clean up any resources.
*/
public void close() {
// empty base implementation
}
/**
* Subclasses may override to indicate that this Dictionary is not yet properly initialized.
*/
public boolean isInitialized() {
return true;
}
}