/ocr/translate/src/com/google/marvin/translate/GoogleTranslate.java

  1/*
  2 * Copyright (C) 2009 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 */
 16package com.google.marvin.translate;
 17
 18import android.util.Log;
 19
 20import org.json.JSONException;
 21import org.json.JSONObject;
 22
 23import java.io.BufferedReader;
 24import java.io.IOException;
 25import java.io.InputStreamReader;
 26import java.net.HttpURLConnection;
 27import java.net.URL;
 28import java.net.URLEncoder;
 29
 30/**
 31 * Connects to the AJAX-accessible Google Translate backend for online
 32 * translation.
 33 * 
 34 * @author alanv@google.com (Alan Viverette)
 35 */
 36public class GoogleTranslate extends Thread {
 37  private static final String TAG = "GoogleTranslate";
 38
 39  private static final String TRANSLATE_URL =
 40      "http://ajax.googleapis.com/ajax/services/language/translate";
 41
 42  private static final String QUERY_PARAM = "q";
 43  private static final String VERSION_PARAM = "v";
 44  private static final String LANGPAIR_PARAM = "langpair";
 45  private static final String LANGPAIR_SEPARATOR = "%7C";
 46  private static final String VERSION = "1.0";
 47
 48  private static final int TIMEOUT = 5000;
 49
 50  private String mStrUrl;
 51  private TranslationListener mCallback;
 52
 53  public interface TranslationListener {
 54    public void onComplete(String result);
 55
 56    public void onError(int code, String error);
 57  }
 58
 59  /**
 60   * Translates a query from a source language to a destination language in a
 61   * separate thread. Takes a TranslationListener that returns the translation
 62   * result (or error status).
 63   * 
 64   * @param query The text to translate.
 65   * @param source The source language code.
 66   * @param target The target language code.
 67   * @param onComplete The translation completion callback.
 68   */
 69  public GoogleTranslate(String query, String source, String target, TranslationListener onComplete) {
 70
 71    query = URLEncoder.encode(query);
 72    source = URLEncoder.encode(source);
 73    target = URLEncoder.encode(target);
 74
 75    String strUrl = TRANSLATE_URL + "?";
 76    strUrl += QUERY_PARAM + "=" + query + "&";
 77    strUrl += VERSION_PARAM + "=" + VERSION + "&";
 78    strUrl += LANGPAIR_PARAM + "=" + source + LANGPAIR_SEPARATOR + target;
 79
 80    mStrUrl = strUrl;
 81    mCallback = onComplete;
 82  }
 83
 84  @Override
 85  public void run() {
 86    if (mCallback == null) {
 87      return;
 88    }
 89
 90    try {
 91      Log.i(TAG, "Connecting to " + mStrUrl);
 92      URL url = new URL(mStrUrl);
 93
 94      Log.i(TAG, "Opening connection with " + TIMEOUT + "ms timeout");
 95      HttpURLConnection conn = (HttpURLConnection) url.openConnection();
 96      conn.setRequestMethod("GET");
 97      conn.setDoOutput(true);
 98      conn.setReadTimeout(TIMEOUT);
 99      conn.connect();
100
101      Log.i(TAG, "Reading content");
102      InputStreamReader reader = new InputStreamReader(conn.getInputStream());
103      BufferedReader buffer = new BufferedReader(reader);
104      String content = "";
105      String line;
106
107      while ((line = buffer.readLine()) != null) {
108        content += line;
109      }
110
111      Log.i(TAG, "Received content:\n" + content);
112
113      conn.disconnect();
114
115      Log.i(TAG, "Interpreting JSON content");
116      JSONObject json = new JSONObject(content.toString());
117      int responseStatus = json.getInt("responseStatus");
118
119      if (responseStatus == 200) {
120        JSONObject responseData = json.getJSONObject("responseData");
121        String translatedText = responseData.getString("translatedText");
122
123        mCallback.onComplete(translatedText);
124      } else {
125        String responseDetails = json.getString("responseDetails");
126
127        mCallback.onError(responseStatus, responseDetails);
128      }
129    } catch (IOException e) {
130      mCallback.onError(0, e.toString());
131    } catch (JSONException e) {
132      mCallback.onError(0, e.toString());
133    }
134
135    mCallback = null;
136  }
137}