/ocr/ocrservice/src/com/googlecode/eyesfree/ocr/service/LanguageManager.java

  1/*
  2 * Copyright (C) 2011 Google Inc.
  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
 17package com.googlecode.eyesfree.ocr.service;
 18
 19import android.content.Context;
 20import android.content.Intent;
 21import android.content.res.Resources;
 22
 23import com.googlecode.eyesfree.ocr.R;
 24import com.googlecode.eyesfree.ocr.client.Intents;
 25import com.googlecode.eyesfree.ocr.client.Language;
 26
 27import java.io.File;
 28import java.io.FilenameFilter;
 29import java.lang.ref.WeakReference;
 30import java.util.ArrayList;
 31import java.util.Collections;
 32import java.util.List;
 33import java.util.Map;
 34import java.util.TreeMap;
 35
 36/**
 37 * Provides a list of installed languages.
 38 *
 39 * @author alanv@google.com (Alan Viverette)
 40 */
 41public class LanguageManager {
 42    private static final String TESSDATA = "tessdata";
 43    private static final String EXTENSION = ".traineddata";
 44    private static final String ENGLISH_UNKNOWN = "Unknown (%s)";
 45    private static final String ISO6391_UNKNOWN = "??";
 46
 47    private File mDatapath;
 48    private File mTessdata;
 49
 50    private Map<String, Language> mSupported;
 51    private List<Language> mAvailable;
 52    private WeakReference<Context> mContext;
 53
 54    public LanguageManager(Context context) {
 55        mContext = new WeakReference<Context>(context);
 56        mSupported = new TreeMap<String, Language>();
 57        mAvailable = new ArrayList<Language>();
 58    }
 59
 60    public boolean loadLanguages() {
 61        Context context = mContext.get();
 62
 63        if (context == null)
 64            return false;
 65
 66        mDatapath = context.getExternalFilesDir(null);
 67
 68        if (mDatapath == null) {
 69            return false;
 70        }
 71
 72        mTessdata = new File(mDatapath, TESSDATA);
 73
 74        loadSupported();
 75        loadAvailable();
 76
 77        // Broadcast intent to let everyone know we've updated the language list
 78        Intent intent = new Intent(Intents.Actions.LANGUAGES_UPDATED);
 79        context.sendBroadcast(intent);
 80
 81        return true;
 82    }
 83
 84    public Map<String, Language> getSupported() {
 85        return mSupported;
 86    }
 87
 88    /**
 89     * Returns the list of available languages. You must call loadLanguages()
 90     * prior to calling this method.
 91     *
 92     * @return the list of available languages
 93     */
 94    public List<Language> getAvailable() {
 95        return mAvailable;
 96    }
 97
 98    /**
 99     * Returns the directory containing tessdata. You must call loadLanguages()
100     * prior to calling this method.
101     *
102     * @return the directory containing tessdata
103     */
104    public File getDatapath() {
105        return mDatapath;
106    }
107
108    /**
109     * Returns the tessdata directory. You must call loadLanguages() prior to
110     * calling this method.
111     *
112     * @return the tessdata directory
113     */
114    public File getTessdata() {
115        return mTessdata;
116    }
117
118    // *******************
119    // * Private methods *
120    // *******************
121
122    private void loadSupported() {
123        mSupported.clear();
124
125        Context context = mContext.get();
126
127        if (context == null)
128            return;
129
130        Resources res = context.getResources();
131
132        String[] english = res.getStringArray(R.array.english);
133        String[] iso6391 = res.getStringArray(R.array.iso_639_1);
134        String[] iso6392 = res.getStringArray(R.array.iso_639_2);
135
136        for (int i = 0; i < english.length; i++) {
137            Language lang = new Language(english[i], iso6391[i], iso6392[i]);
138
139            mSupported.put(iso6392[i], lang);
140        }
141    }
142
143    private void loadAvailable() {
144        mAvailable.clear();
145
146        if (mTessdata == null)
147            return;
148
149        String[] files = mTessdata.list(trainedDataFilter);
150
151        if (files == null)
152            return;
153
154        for (String file : files) {
155            int lastIndex = file.lastIndexOf('.');
156            String iso6392 = file.substring(0, lastIndex);
157            Language lang = mSupported.get(iso6392);
158
159            if (lang == null) {
160                String english = String.format(ENGLISH_UNKNOWN, iso6392);
161                lang = new Language(english, ISO6391_UNKNOWN, iso6392);
162            }
163
164            mAvailable.add(lang);
165        }
166
167        Collections.sort(mAvailable);
168    }
169
170    // *******************
171    // * Private classes *
172    // *******************
173
174    private FilenameFilter trainedDataFilter = new FilenameFilter() {
175        @Override
176        public boolean accept(File dir, String filename) {
177            return filename.endsWith(EXTENSION);
178        }
179    };
180}