speech/tts/TextToSpeech.java

/*
 * Copyright (C) 2009 Google Inc.
 *
 * 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 android.speech.tts;

import android.speech.tts.ITts;
import android.speech.tts.ITtsCallback;

import android.annotation.SdkConstant;
import android.annotation.SdkConstant.SdkConstantType;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.media.AudioManager;
import android.os.IBinder;
import android.os.RemoteException;
import android.util.Log;

import java.util.HashMap;
import java.util.Locale;

/**
 *
 * Synthesizes speech from text for immediate playback or to create a sound file.
 * <p>A TextToSpeech instance can only be used to synthesize text once it has completed its
 * initialization. Implement the {@link TextToSpeech.OnInitListener} to be
 * notified of the completion of the initialization.<br>
 * When you are done using the TextToSpeech instance, call the {@link #shutdown()} method
 * to release the native resources used by the TextToSpeech engine.
 *
 */
public class TextToSpeech {

    private static final String TAG = "TextToSpeech";

    /**
     * Denotes a successful operation.
     */
    public static final int SUCCESS                = 0;
    /**
     * Denotes a generic operation failure.
     */
    public static final int ERROR                  = -1;

    /**
     * Queue mode where all entries in the playback queue (media to be played
     * and text to be synthesized) are dropped and replaced by the new entry.
     */
    public static final int QUEUE_FLUSH = 0;
    /**
     * Queue mode where the new entry is added at the end of the playback queue.
     */
    public static final int QUEUE_ADD = 1;


    /**
     * Denotes the language is available exactly as specified by the locale.
     */
    public static final int LANG_COUNTRY_VAR_AVAILABLE = 2;


    /**
     * Denotes the language is available for the language and country specified
     * by the locale, but not the variant.
     */
    public static final int LANG_COUNTRY_AVAILABLE = 1;


    /**
     * Denotes the language is available for the language by the locale,
     * but not the country and variant.
     */
    public static final int LANG_AVAILABLE = 0;

    /**
     * Denotes the language data is missing.
     */
    public static final int LANG_MISSING_DATA = -1;

    /**
     * Denotes the language is not supported.
     */
    public static final int LANG_NOT_SUPPORTED = -2;


    /**
     * Broadcast Action: The TextToSpeech synthesizer has completed processing
     * of all the text in the speech queue.
     */
    @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
    public static final String ACTION_TTS_QUEUE_PROCESSING_COMPLETED =
            "android.speech.tts.TTS_QUEUE_PROCESSING_COMPLETED";


    /**
     * Interface definition of a callback to be invoked indicating the completion of the
     * TextToSpeech engine initialization.
     */
    public interface OnInitListener {
        /**
         * Called to signal the completion of the TextToSpeech engine initialization.
         * @param status {@link TextToSpeech#SUCCESS} or {@link TextToSpeech#ERROR}.
         */
        public void onInit(int status);
    }

    /**
     * Interface definition of a callback to be invoked indicating the TextToSpeech engine has
     * completed synthesizing an utterance with an utterance ID set.
     *
     */
    public interface OnUtteranceCompletedListener {
        /**
         * Called to signal the completion of the synthesis of the utterance that was identified
         * with the string parameter. This identifier is the one originally passed in the
         * parameter hashmap of the synthesis request in
         * {@link TextToSpeech#speak(String, int, HashMap)} or
         * {@link TextToSpeech#synthesizeToFile(String, HashMap, String)} with the
         * {@link TextToSpeech.Engine#KEY_PARAM_UTTERANCE_ID} key.
         * @param utteranceId the identifier of the utterance.
         */
        public void onUtteranceCompleted(String utteranceId);
    }


    /**
     * Internal constants for the TextToSpeech functionality
     *
     */
    public class Engine {
        // default values for a TTS engine when settings are not found in the provider
        /**
         * {@hide}
         */
        public static final int DEFAULT_RATE = 100; // 1x
        /**
         * {@hide}
         */
        public static final int DEFAULT_PITCH = 100;// 1x
        /**
         * {@hide}
         */
        public static final float DEFAULT_VOLUME = 1.0f;
        /**
         * {@hide}
         */
        protected static final String DEFAULT_VOLUME_STRING = "1.0";
        /**
         * {@hide}
         */
        public static final float DEFAULT_PAN = 0.0f;
        /**
         * {@hide}
         */
        protected static final String DEFAULT_PAN_STRING = "0.0";

        /**
         * {@hide}
         */
        public static final int USE_DEFAULTS = 0; // false
        /**
         * {@hide}
         */
        public static final String DEFAULT_SYNTH = "com.svox.pico";

        // default values for rendering
        /**
         * Default audio stream used when playing synthesized speech.
         */
        public static final int DEFAULT_STREAM = AudioManager.STREAM_MUSIC;

        // return codes for a TTS engine's check data activity
        /**
         * Indicates success when checking the installation status of the resources used by the
         * TextToSpeech engine with the {@link #ACTION_CHECK_TTS_DATA} intent.
         */
        public static final int CHECK_VOICE_DATA_PASS = 1;
        /**
         * Indicates failure when checking the installation status of the resources used by the
         * TextToSpeech engine with the {@link #ACTION_CHECK_TTS_DATA} intent.
         */
        public static final int CHECK_VOICE_DATA_FAIL = 0;
        /**
         * Indicates erroneous data when checking the installation status of the resources used by
         * the TextToSpeech engine with the {@link #ACTION_CHECK_TTS_DATA} intent.
         */
        public static final int CHECK_VOICE_DATA_BAD_DATA = -1;
        /**
         * Indicates missing resources when checking the installation status of the resources used
         * by the TextToSpeech engine with the {@link #ACTION_CHECK_TTS_DATA} intent.
         */
        public static final int CHECK_VOICE_DATA_MISSING_DATA = -2;
        /**
         * Indicates missing storage volume when checking the installation status of the resources
         * used by the TextToSpeech engine with the {@link #ACTION_CHECK_TTS_DATA} intent.
         */
        public static final int CHECK_VOICE_DATA_MISSING_VOLUME = -3;

        // intents to ask engine to install data or check its data
        /**
         * Activity Action: Triggers the platform TextToSpeech engine to
         * start the activity that installs the resource files on the device
         * that are required for TTS to be operational. Since the installation
         * of the data can be interrupted or declined by the user, the application
         * shouldn't expect successful installation upon return from that intent,
         * and if need be, should check installation status with
         * {@link #ACTION_CHECK_TTS_DATA}.
         */
        @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
        public static final String ACTION_INSTALL_TTS_DATA =
                "android.speech.tts.engine.INSTALL_TTS_DATA";

        /**
         * Broadcast Action: broadcast to signal the completion of the installation of
         * the data files used by the synthesis engine. Success or failure is indicated in the
         * {@link #EXTRA_TTS_DATA_INSTALLED} extra.
         */
        @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
        public static final String ACTION_TTS_DATA_INSTALLED =
                "android.speech.tts.engine.TTS_DATA_INSTALLED";
        /**
         * Activity Action: Starts the activity from the platform TextToSpeech
         * engine to verify the proper installation and availability of the
         * resource files on the system. Upon completion, the activity will
         * return one of the following codes:
         * {@link #CHECK_VOICE_DATA_PASS},
         * {@link #CHECK_VOICE_DATA_FAIL},
         * {@link #CHECK_VOICE_DATA_BAD_DATA},
         * {@link #CHECK_VOICE_DATA_MISSING_DATA}, or
         * {@link #CHECK_VOICE_DATA_MISSING_VOLUME}.
         * <p> Moreover, the data received in the activity result will contain the following
         * fields:
         * <ul>
         *   <li>{@link #EXTRA_VOICE_DATA_ROOT_DIRECTORY} which
         *       indicates the path to the location of the resource files,</li>
         *   <li>{@link #EXTRA_VOICE_DATA_FILES} which contains
         *       the list of all the resource files,</li>
         *   <li>and {@link #EXTRA_VOICE_DATA_FILES_INFO} which
         *       contains, for each resource file, the description of the language covered by
         *       the file in the xxx-YYY format, where xxx is the 3-letter ISO language code,
         *       and YYY is the 3-letter ISO country code.</li>
         * </ul>
         */
        @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
        public static final String ACTION_CHECK_TTS_DATA =
                "android.speech.tts.engine.CHECK_TTS_DATA";

        // extras for a TTS engine's check data activity
        /**
         * Extra information received with the {@link #ACTION_CHECK_TTS_DATA} intent where
         * the TextToSpeech engine specifies the path to its resources.
         */
        public static final String EXTRA_VOICE_DATA_ROOT_DIRECTORY = "dataRoot";
        /**
         * Extra information received with the {@link #ACTION_CHECK_TTS_DATA} intent where
         * the TextToSpeech engine specifies the file names of its resources under the
         * resource path.
         */
        public static final String EXTRA_VOICE_DATA_FILES = "dataFiles";
        /**
         * Extra information received with the {@link #ACTION_CHECK_TTS_DATA} intent where
         * the TextToSpeech engine specifies the locale associated with each resource file.
         */
        public static final String EXTRA_VOICE_DATA_FILES_INFO = "dataFilesInfo";
        /**
         * Extra information received with the {@link #ACTION_CHECK_TTS_DATA} intent where
         * the TextToSpeech engine returns an ArrayList<String> of all the available voices.
         * The format of each voice is: lang-COUNTRY-variant where COUNTRY and variant are
         * optional (ie, "eng" or "eng-USA" or "eng-USA-FEMALE").
         */
        public static final String EXTRA_AVAILABLE_VOICES = "availableVoices";
        /**
         * Extra information received with the {@link #ACTION_CHECK_TTS_DATA} intent where
         * the TextToSpeech engine returns an ArrayList<String> of all the unavailable voices.
         * The format of each voice is: lang-COUNTRY-variant where COUNTRY and variant are
         * optional (ie, "eng" or "eng-USA" or "eng-USA-FEMALE").
         */
        public static final String EXTRA_UNAVAILABLE_VOICES = "unavailableVoices";
        /**
         * Extra information sent with the {@link #ACTION_CHECK_TTS_DATA} intent where the
         * caller indicates to the TextToSpeech engine which specific sets of voice data to
         * check for by sending an ArrayList<String> of the voices that are of interest.
         * The format of each voice is: lang-COUNTRY-variant where COUNTRY and variant are
         * optional (ie, "eng" or "eng-USA" or "eng-USA-FEMALE").
         */
        public static final String EXTRA_CHECK_VOICE_DATA_FOR = "checkVoiceDataFor";

        // extras for a TTS engine's data installation
        /**
         * Extra information received with the {@link #ACTION_TTS_DATA_INSTALLED} intent.
         * It indicates whether the data files for the synthesis engine were successfully
         * installed. The installation was initiated with the  {@link #ACTION_INSTALL_TTS_DATA}
         * intent. The possible values for this extra are
         * {@link TextToSpeech#SUCCESS} and {@link TextToSpeech#ERROR}.
         */
        public static final String EXTRA_TTS_DATA_INSTALLED = "dataInstalled";

        // keys for the parameters passed with speak commands. Hidden keys are used internally
        // to maintain engine state for each TextToSpeech instance.
        /**
         * {@hide}
         */
        public static final String KEY_PARAM_RATE = "rate";
        /**
         * {@hide}
         */
        public static final String KEY_PARAM_LANGUAGE = "language";
        /**
         * {@hide}
         */
        public static final String KEY_PARAM_COUNTRY = "country";
        /**
         * {@hide}
         */
        public static final String KEY_PARAM_VARIANT = "variant";
        /**
         * {@hide}
         */
        public static final String KEY_PARAM_ENGINE = "engine";
        /**
         * {@hide}
         */
        public static final String KEY_PARAM_PITCH = "pitch";
        /**
         * Parameter key to specify the audio stream type to be used when speaking text
         * or playing back a file.
         * @see TextToSpeech#speak(String, int, HashMap)
         * @see TextToSpeech#playEarcon(String, int, HashMap)
         */
        public static final String KEY_PARAM_STREAM = "streamType";
        /**
         * Parameter key to identify an utterance in the
         * {@link TextToSpeech.OnUtteranceCompletedListener} after text has been
         * spoken, a file has been played back or a silence duration has elapsed.
         * @see TextToSpeech#speak(String, int, HashMap)
         * @see TextToSpeech#playEarcon(String, int, HashMap)
         * @see TextToSpeech#synthesizeToFile(String, HashMap, String)
         */
        public static final String KEY_PARAM_UTTERANCE_ID = "utteranceId";
        /**
         * Parameter key to specify the speech volume relative to the current stream type
         * volume used when speaking text. Volume is specified as a float ranging from 0 to 1
         * where 0 is silence, and 1 is the maximum volume (the default behavior).
         * @see TextToSpeech#speak(String, int, HashMap)
         * @see TextToSpeech#playEarcon(String, int, HashMap)
         */
        public static final String KEY_PARAM_VOLUME = "volume";
        /**
         * Parameter key to specify how the speech is panned from left to right when speaking text.
         * Pan is specified as a float ranging from -1 to +1 where -1 maps to a hard-left pan,
         * 0 to center (the default behavior), and +1 to hard-right.
         * @see TextToSpeech#speak(String, int, HashMap)
         * @see TextToSpeech#playEarcon(String, int, HashMap)
         */
        public static final String KEY_PARAM_PAN = "pan";

        // key positions in the array of cached parameters
        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_RATE = 0;
        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_LANGUAGE = 2;
        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_COUNTRY = 4;
        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_VARIANT = 6;
        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_STREAM = 8;
        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_UTTERANCE_ID = 10;

        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_ENGINE = 12;

        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_PITCH = 14;

        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_VOLUME = 16;

        /**
         * {@hide}
         */
        protected static final int PARAM_POSITION_PAN = 18;


        /**
         * {@hide}
         * Total number of cached speech parameters.
         * This number should be equal to (max param position/2) + 1.
         */
        protected static final int NB_CACHED_PARAMS = 10;
    }

    /**
     * Connection needed for the TTS.
     */
    private ServiceConnection mServiceConnection;

    private ITts mITts = null;
    private ITtsCallback mITtscallback = null;
    private Context mContext = null;
    private String mPackageName = "";
    private OnInitListener mInitListener = null;
    private boolean mStarted = false;
    private final Object mStartLock = new Object();
    /**
     * Used to store the cached parameters sent along with each synthesis request to the
     * TTS service.
     */
    private String[] mCachedParams;

    /**
     * The constructor for the TextToSpeech class.
     * This will also initialize the associated TextToSpeech engine if it isn't already running.
     *
     * @param context
     *            The context this instance is running in.
     * @param listener
     *            The {@link TextToSpeech.OnInitListener} that will be called when the
     *            TextToSpeech engine has initialized.
     */
    public TextToSpeech(Context context, OnInitListener listener) {
        mContext = context;
        mPackageName = mContext.getPackageName();
        mInitListener = listener;

        mCachedParams = new String[2*Engine.NB_CACHED_PARAMS]; // store key and value
        mCachedParams[Engine.PARAM_POSITION_RATE] = Engine.KEY_PARAM_RATE;
        mCachedParams[Engine.PARAM_POSITION_LANGUAGE] = Engine.KEY_PARAM_LANGUAGE;
        mCachedParams[Engine.PARAM_POSITION_COUNTRY] = Engine.KEY_PARAM_COUNTRY;
        mCachedParams[Engine.PARAM_POSITION_VARIANT] = Engine.KEY_PARAM_VARIANT;
        mCachedParams[Engine.PARAM_POSITION_STREAM] = Engine.KEY_PARAM_STREAM;
        mCachedParams[Engine.PARAM_POSITION_UTTERANCE_ID] = Engine.KEY_PARAM_UTTERANCE_ID;
        mCachedParams[Engine.PARAM_POSITION_ENGINE] = Engine.KEY_PARAM_ENGINE;
        mCachedParams[Engine.PARAM_POSITION_PITCH] = Engine.KEY_PARAM_PITCH;
        mCachedParams[Engine.PARAM_POSITION_VOLUME] = Engine.KEY_PARAM_VOLUME;
        mCachedParams[Engine.PARAM_POSITION_PAN] = Engine.KEY_PARAM_PAN;

        // Leave all defaults that are shown in Settings uninitialized/at the default
        // so that the values set in Settings will take effect if the application does
        // not try to change these settings itself.
        mCachedParams[Engine.PARAM_POSITION_RATE + 1] = "";
        mCachedParams[Engine.PARAM_POSITION_LANGUAGE + 1] = "";
        mCachedParams[Engine.PARAM_POSITION_COUNTRY + 1] = "";
        mCachedParams[Engine.PARAM_POSITION_VARIANT + 1] = "";
        mCachedParams[Engine.PARAM_POSITION_STREAM + 1] =
                String.valueOf(Engine.DEFAULT_STREAM);
        mCachedParams[Engine.PARAM_POSITION_UTTERANCE_ID + 1] = "";
        mCachedParams[Engine.PARAM_POSITION_ENGINE + 1] = "";
        mCachedParams[Engine.PARAM_POSITION_PITCH + 1] = "100";
        mCachedParams[Engine.PARAM_POSITION_VOLUME + 1] = Engine.DEFAULT_VOLUME_STRING;
        mCachedParams[Engine.PARAM_POSITION_PAN + 1] = Engine.DEFAULT_PAN_STRING;

        initTts();
    }


    private void initTts() {
        mStarted = false;

        // Initialize the TTS, run the callback after the binding is successful
        mServiceConnection = new ServiceConnection() {
            public void onServiceConnected(ComponentName name, IBinder service) {
                synchronized(mStartLock) {
                    mITts = ITts.Stub.asInterface(service);
                    mStarted = true;
                    // Cache the default engine and current language
                    setEngineByPackageName(getDefaultEngine());
                    setLanguage(getLanguage());
                    if (mInitListener != null) {
                        // TODO manage failures and missing resources
                        mInitListener.onInit(SUCCESS);
                    }
                }
            }

            public void onServiceDisconnected(ComponentName name) {
                synchronized(mStartLock) {
                    mITts = null;
                    mInitListener = null;
                    mStarted = false;
                }
            }
        };

        Intent intent = new Intent("android.intent.action.START_TTS_SERVICE");
        intent.addCategory("android.intent.category.TTS");
        boolean bound = mContext.bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
        if (!bound) {
            Log.e("TextToSpeech.java", "initTts() failed to bind to service");
            if (mInitListener != null) {
                mInitListener.onInit(ERROR);
            }
        } else {
            // initialization listener will be called inside ServiceConnection
            Log.i("TextToSpeech.java", "initTts() successfully bound to service");
        }
        // TODO handle plugin failures
    }


    /**
     * Releases the resources used by the TextToSpeech engine.
     * It is good practice for instance to call this method in the onDestroy() method of an Activity
     * so the TextToSpeech engine can be cleanly stopped.
     */
    public void shutdown() {
        try {
            mContext.unbindService(mServiceConnection);
        } catch (IllegalArgumentException e) {
            // Do nothing and fail silently since an error here indicates that
            // binding never succeeded in the first place.
        }
    }


    /**
     * Adds a mapping between a string of text and a sound resource in a
     * package. After a call to this method, subsequent calls to
     * {@link #speak(String, int, HashMap)} will play the specified sound resource
     * if it is available, or synthesize the text it is missing.
     *
     * @param text
     *            The string of text. Example: <code>"south_south_east"</code>
     *
     * @param packagename
     *            Pass the packagename of the application that contains the
     *            resource. If the resource is in your own application (this is
     *            the most common case), then put the packagename of your
     *            application here.<br/>
     *            Example: <b>"com.google.marvin.compass"</b><br/>
     *            The packagename can be found in the AndroidManifest.xml of
     *            your application.
     *            <p>
     *            <code>&lt;manifest xmlns:android=&quot;...&quot;
     *      package=&quot;<b>com.google.marvin.compass</b>&quot;&gt;</code>
     *            </p>
     *
     * @param resourceId
     *            Example: <code>R.raw.south_south_east</code>
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int addSpeech(String text, String packagename, int resourceId) {
        synchronized(mStartLock) {
            if (!mStarted) {
                return ERROR;
            }
            try {
                mITts.addSpeech(mPackageName, text, packagename, resourceId);
                return SUCCESS;
            } catch (RemoteException e) {
                restart("addSpeech", e);
            } catch (NullPointerException e) {
                restart("addSpeech", e);
            } catch (IllegalStateException e) {
                restart("addSpeech", e);
            }
            return ERROR;
        }
    }

    /**
     * Adds a mapping between a string of text and a sound file. Using this, it
     * is possible to add custom pronounciations for a string of text.
     * After a call to this method, subsequent calls to {@link #speak(String, int, HashMap)}
     * will play the specified sound resource if it is available, or synthesize the text it is
     * missing.
     *
     * @param text
     *            The string of text. Example: <code>"south_south_east"</code>
     * @param filename
     *            The full path to the sound file (for example:
     *            "/sdcard/mysounds/hello.wav")
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int addSpeech(String text, String filename) {
        synchronized (mStartLock) {
            if (!mStarted) {
                return ERROR;
            }
            try {
                mITts.addSpeechFile(mPackageName, text, filename);
                return SUCCESS;
            } catch (RemoteException e) {
                restart("addSpeech", e);
            } catch (NullPointerException e) {
                restart("addSpeech", e);
            } catch (IllegalStateException e) {
                restart("addSpeech", e);
            }
            return ERROR;
        }
    }


    /**
     * Adds a mapping between a string of text and a sound resource in a
     * package. Use this to add custom earcons.
     *
     * @see #playEarcon(String, int, HashMap)
     *
     * @param earcon The name of the earcon.
     *            Example: <code>"[tick]"</code><br/>
     *
     * @param packagename
     *            the package name of the application that contains the
     *            resource. This can for instance be the package name of your own application.
     *            Example: <b>"com.google.marvin.compass"</b><br/>
     *            The package name can be found in the AndroidManifest.xml of
     *            the application containing the resource.
     *            <p>
     *            <code>&lt;manifest xmlns:android=&quot;...&quot;
     *      package=&quot;<b>com.google.marvin.compass</b>&quot;&gt;</code>
     *            </p>
     *
     * @param resourceId
     *            Example: <code>R.raw.tick_snd</code>
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int addEarcon(String earcon, String packagename, int resourceId) {
        synchronized(mStartLock) {
            if (!mStarted) {
                return ERROR;
            }
            try {
                mITts.addEarcon(mPackageName, earcon, packagename, resourceId);
                return SUCCESS;
            } catch (RemoteException e) {
                restart("addEarcon", e);
            } catch (NullPointerException e) {
                restart("addEarcon", e);
            } catch (IllegalStateException e) {
                restart("addEarcon", e);
            }
            return ERROR;
        }
    }


    /**
     * Adds a mapping between a string of text and a sound file.
     * Use this to add custom earcons.
     *
     * @see #playEarcon(String, int, HashMap)
     *
     * @param earcon
     *            The name of the earcon.
     *            Example: <code>"[tick]"</code>
     * @param filename
     *            The full path to the sound file (for example:
     *            "/sdcard/mysounds/tick.wav")
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int addEarcon(String earcon, String filename) {
        synchronized (mStartLock) {
            if (!mStarted) {
                return ERROR;
            }
            try {
                mITts.addEarconFile(mPackageName, earcon, filename);
                return SUCCESS;
            } catch (RemoteException e) {
                restart("addEarcon", e);
            } catch (NullPointerException e) {
                restart("addEarcon", e);
            } catch (IllegalStateException e) {
                restart("addEarcon", e);
            }
            return ERROR;
        }
    }


    /**
     * Speaks the string using the specified queuing strategy and speech
     * parameters.
     *
     * @param text
     *            The string of text to be spoken.
     * @param queueMode
     *            The queuing strategy to use.
     *            {@link #QUEUE_ADD} or {@link #QUEUE_FLUSH}.
     * @param params
     *            The list of parameters to be used. Can be null if no parameters are given.
     *            They are specified using a (key, value) pair, where the key can be
     *            {@link Engine#KEY_PARAM_STREAM} or
     *            {@link Engine#KEY_PARAM_UTTERANCE_ID}.
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int speak(String text, int queueMode, HashMap<String,String> params)
    {
        synchronized (mStartLock) {
            int result = ERROR;
            Log.i("TextToSpeech.java - speak", "speak text of length " + text.length());
            if (!mStarted) {
                Log.e("TextToSpeech.java - speak", "service isn't started");
                return result;
            }
            try {
                if ((params != null) && (!params.isEmpty())) {
                    setCachedParam(params, Engine.KEY_PARAM_STREAM, Engine.PARAM_POSITION_STREAM);
                    setCachedParam(params, Engine.KEY_PARAM_UTTERANCE_ID,
                            Engine.PARAM_POSITION_UTTERANCE_ID);
                    setCachedParam(params, Engine.KEY_PARAM_ENGINE, Engine.PARAM_POSITION_ENGINE);
                    setCachedParam(params, Engine.KEY_PARAM_VOLUME, Engine.PARAM_POSITION_VOLUME);
                    setCachedParam(params, Engine.KEY_PARAM_PAN, Engine.PARAM_POSITION_PAN);
                }
                result = mITts.speak(mPackageName, text, queueMode, mCachedParams);
            } catch (RemoteException e) {
                restart("speak", e);
            } catch (NullPointerException e) {
                restart("speak", e);
            } catch (IllegalStateException e) {
                restart("speak", e);
            } finally {
                resetCachedParams();
            }
            return result;
        }
    }


    /**
     * Plays the earcon using the specified queueing mode and parameters.
     *
     * @param earcon
     *            The earcon that should be played
     * @param queueMode
     *            {@link #QUEUE_ADD} or {@link #QUEUE_FLUSH}.
     * @param params
     *            The list of parameters to be used. Can be null if no parameters are given.
     *            They are specified using a (key, value) pair, where the key can be
     *            {@link Engine#KEY_PARAM_STREAM} or
     *            {@link Engine#KEY_PARAM_UTTERANCE_ID}.
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int playEarcon(String earcon, int queueMode,
            HashMap<String,String> params) {
        synchronized (mStartLock) {
            int result = ERROR;
            if (!mStarted) {
                return result;
            }
            try {
                if ((params != null) && (!params.isEmpty())) {
                    String extra = params.get(Engine.KEY_PARAM_STREAM);
                    if (extra != null) {
                        mCachedParams[Engine.PARAM_POSITION_STREAM + 1] = extra;
                    }
                    setCachedParam(params, Engine.KEY_PARAM_STREAM, Engine.PARAM_POSITION_STREAM);
                    setCachedParam(params, Engine.KEY_PARAM_UTTERANCE_ID,
                            Engine.PARAM_POSITION_UTTERANCE_ID);
                }
                result = mITts.playEarcon(mPackageName, earcon, queueMode, null);
            } catch (RemoteException e) {
                restart("playEarcon", e);
            } catch (NullPointerException e) {
                restart("playEarcon", e);
            } catch (IllegalStateException e) {
                restart("playEarcon", e);
            } finally {
                resetCachedParams();
            }
            return result;
        }
    }

    /**
     * Plays silence for the specified amount of time using the specified
     * queue mode.
     *
     * @param durationInMs
     *            A long that indicates how long the silence should last.
     * @param queueMode
     *            {@link #QUEUE_ADD} or {@link #QUEUE_FLUSH}.
     * @param params
     *            The list of parameters to be used. Can be null if no parameters are given.
     *            They are specified using a (key, value) pair, where the key can be
     *            {@link Engine#KEY_PARAM_UTTERANCE_ID}.
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int playSilence(long durationInMs, int queueMode, HashMap<String,String> params) {
        synchronized (mStartLock) {
            int result = ERROR;
            if (!mStarted) {
                return result;
            }
            try {
                if ((params != null) && (!params.isEmpty())) {
                    setCachedParam(params, Engine.KEY_PARAM_UTTERANCE_ID,
                            Engine.PARAM_POSITION_UTTERANCE_ID);
                }
                result = mITts.playSilence(mPackageName, durationInMs, queueMode, mCachedParams);
            } catch (RemoteException e) {
                restart("playSilence", e);
            } catch (NullPointerException e) {
                restart("playSilence", e);
            } catch (IllegalStateException e) {
                restart("playSilence", e);
            } finally {
                resetCachedParams();
            }
            return result;
        }
    }


    /**
     * Returns whether or not the TextToSpeech engine is busy speaking.
     *
     * @return Whether or not the TextToSpeech engine is busy speaking.
     */
    public boolean isSpeaking() {
        synchronized (mStartLock) {
            if (!mStarted) {
                return false;
            }
            try {
                return mITts.isSpeaking();
            } catch (RemoteException e) {
                restart("isSpeaking", e);
            } catch (NullPointerException e) {
                restart("isSpeaking", e);
            } catch (IllegalStateException e) {
                restart("isSpeaking", e);
            }
            return false;
        }
    }


    /**
     * Interrupts the current utterance (whether played or rendered to file) and discards other
     * utterances in the queue.
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int stop() {
        synchronized (mStartLock) {
            int result = ERROR;
            if (!mStarted) {
                return result;
            }
            try {
                result = mITts.stop(mPackageName);
            } catch (RemoteException e) {
                restart("stop", e);
            } catch (NullPointerException e) {
                restart("stop", e);
            } catch (IllegalStateException e) {
                restart("stop", e);
            }
            return result;
        }
    }


    /**
     * Sets the speech rate for the TextToSpeech engine.
     *
     * This has no effect on any pre-recorded speech.
     *
     * @param speechRate
     *            The speech rate for the TextToSpeech engine. 1 is the normal speed,
     *            lower values slow down the speech (0.5 is half the normal speech rate),
     *            greater values accelerate it (2 is twice the normal speech rate).
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int setSpeechRate(float speechRate) {
        synchronized (mStartLock) {
            int result = ERROR;
            if (!mStarted) {
                return result;
            }
            try {
                if (speechRate > 0) {
                    int rate = (int)(speechRate*100);
                    mCachedParams[Engine.PARAM_POSITION_RATE + 1] = String.valueOf(rate);
                    // the rate is not set here, instead it is cached so it will be associated
                    // with all upcoming utterances.
                    if (speechRate > 0.0f) {
                        result = SUCCESS;
                    } else {
                        result = ERROR;
                    }
                }
            } catch (NullPointerException e) {
                restart("setSpeechRate", e);
            } catch (IllegalStateException e) {
                restart("setSpeechRate", e);
            }
            return result;
        }
    }


    /**
     * Sets the speech pitch for the TextToSpeech engine.
     *
     * This has no effect on any pre-recorded speech.
     *
     * @param pitch
     *            The pitch for the TextToSpeech engine. 1 is the normal pitch,
     *            lower values lower the tone of the synthesized voice,
     *            greater values increase it.
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int setPitch(float pitch) {
        synchronized (mStartLock) {
            int result = ERROR;
            if (!mStarted) {
                return result;
            }
            try {
                // the pitch is not set here, instead it is cached so it will be associated
                // with all upcoming utterances.
                if (pitch > 0) {
                    int p = (int)(pitch*100);
                    mCachedParams[Engine.PARAM_POSITION_PITCH + 1] = String.valueOf(p);
                    result = SUCCESS;
                }
            } catch (NullPointerException e) {
                restart("setPitch", e);
            } catch (IllegalStateException e) {
                restart("setPitch", e);
            }
            return result;
        }
    }


    /**
     * Sets the language for the TextToSpeech engine.
     * The TextToSpeech engine will try to use the closest match to the specified
     * language as represented by the Locale, but there is no guarantee that the exact same Locale
     * will be used. Use {@link #isLanguageAvailable(Locale)} to check the level of support
     * before choosing the language to use for the next utterances.
     *
     * @param loc
     *            The locale describing the language to be used.
     *
     * @return code indicating the support status for the locale. See {@link #LANG_AVAILABLE},
     *         {@link #LANG_COUNTRY_AVAILABLE}, {@link #LANG_COUNTRY_VAR_AVAILABLE},
     *         {@link #LANG_MISSING_DATA} and {@link #LANG_NOT_SUPPORTED}.
     */
    public int setLanguage(Locale loc) {
        synchronized (mStartLock) {
            int result = LANG_NOT_SUPPORTED;
            if (!mStarted) {
                return result;
            }
            if (loc == null) {
                return result;
            }
            try {
                String language = loc.getISO3Language();
                String country = loc.getISO3Country();
                String variant = loc.getVariant();
                // Check if the language, country, variant are available, and cache
                // the available parts.
                // Note that the language is not actually set here, instead it is cached so it
                // will be associated with all upcoming utterances.
                result = mITts.isLanguageAvailable(language, country, variant, mCachedParams);
                if (result >= LANG_AVAILABLE){
                    mCachedParams[Engine.PARAM_POSITION_LANGUAGE + 1] = language;
                    if (result >= LANG_COUNTRY_AVAILABLE){
                        mCachedParams[Engine.PARAM_POSITION_COUNTRY + 1] = country;
                    } else {
                        mCachedParams[Engine.PARAM_POSITION_COUNTRY + 1] = "";
                    }
                    if (result >= LANG_COUNTRY_VAR_AVAILABLE){
                        mCachedParams[Engine.PARAM_POSITION_VARIANT + 1] = variant;
                    } else {
                        mCachedParams[Engine.PARAM_POSITION_VARIANT + 1] = "";
                    }
                }
            } catch (RemoteException e) {
                restart("setLanguage", e);
            } catch (NullPointerException e) {
                restart("setLanguage", e);
            } catch (IllegalStateException e) {
                restart("setLanguage", e);
            }
            return result;
        }
    }


    /**
     * Returns a Locale instance describing the language currently being used by the TextToSpeech
     * engine.
     * @return language, country (if any) and variant (if any) used by the engine stored in a Locale
     *     instance, or null is the TextToSpeech engine has failed.
     */
    public Locale getLanguage() {
        synchronized (mStartLock) {
            if (!mStarted) {
                return null;
            }
            try {
                // Only do a call to the native synth if there is nothing in the cached params
                if (mCachedParams[Engine.PARAM_POSITION_LANGUAGE + 1].length() < 1){
                    String[] locStrings = mITts.getLanguage();
                    if ((locStrings != null) && (locStrings.length == 3)) {
                        return new Locale(locStrings[0], locStrings[1], locStrings[2]);
                    } else {
                        return null;
                    }
                } else {
                    return new Locale(mCachedParams[Engine.PARAM_POSITION_LANGUAGE + 1],
                            mCachedParams[Engine.PARAM_POSITION_COUNTRY + 1],
                            mCachedParams[Engine.PARAM_POSITION_VARIANT + 1]);
                }
            } catch (RemoteException e) {
                restart("getLanguage", e);
            } catch (NullPointerException e) {
                restart("getLanguage", e);
            } catch (IllegalStateException e) {
                restart("getLanguage", e);
            }
            return null;
        }
    }

    /**
     * Checks if the specified language as represented by the Locale is available and supported.
     *
     * @param loc
     *            The Locale describing the language to be used.
     *
     * @return code indicating the support status for the locale. See {@link #LANG_AVAILABLE},
     *         {@link #LANG_COUNTRY_AVAILABLE}, {@link #LANG_COUNTRY_VAR_AVAILABLE},
     *         {@link #LANG_MISSING_DATA} and {@link #LANG_NOT_SUPPORTED}.
     */
    public int isLanguageAvailable(Locale loc) {
        synchronized (mStartLock) {
            int result = LANG_NOT_SUPPORTED;
            if (!mStarted) {
                return result;
            }
            try {
                result = mITts.isLanguageAvailable(loc.getISO3Language(),
                        loc.getISO3Country(), loc.getVariant(), mCachedParams);
            } catch (RemoteException e) {
                restart("isLanguageAvailable", e);
            } catch (NullPointerException e) {
                restart("isLanguageAvailable", e);
            } catch (IllegalStateException e) {
                restart("isLanguageAvailable", e);
            }
            return result;
        }
    }


    /**
     * Synthesizes the given text to a file using the specified parameters.
     *
     * @param text
     *            The String of text that should be synthesized
     * @param params
     *            The list of parameters to be used. Can be null if no parameters are given.
     *            They are specified using a (key, value) pair, where the key can be
     *            {@link Engine#KEY_PARAM_UTTERANCE_ID}.
     * @param filename
     *            The string that gives the full output filename; it should be
     *            something like "/sdcard/myappsounds/mysound.wav".
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int synthesizeToFile(String text, HashMap<String,String> params,
            String filename) {
        Log.i("TextToSpeech.java", "synthesizeToFile()");
        synchronized (mStartLock) {
            int result = ERROR;
            Log.i("TextToSpeech.java - synthesizeToFile", "synthesizeToFile text of length "
                    + text.length());
            if (!mStarted) {
                Log.e("TextToSpeech.java - synthesizeToFile", "service isn't started");
                return result;
            }
            try {
                if ((params != null) && (!params.isEmpty())) {
                    // no need to read the stream type here
                    setCachedParam(params, Engine.KEY_PARAM_UTTERANCE_ID,
                            Engine.PARAM_POSITION_UTTERANCE_ID);
                    setCachedParam(params, Engine.KEY_PARAM_ENGINE, Engine.PARAM_POSITION_ENGINE);
                }
                result = mITts.synthesizeToFile(mPackageName, text, mCachedParams, filename) ?
                        SUCCESS : ERROR;
            } catch (RemoteException e) {
                restart("synthesizeToFile", e);
            } catch (NullPointerException e) {
                restart("synthesizeToFile", e);
            } catch (IllegalStateException e) {
                restart("synthesizeToFile", e);
            } finally {
                resetCachedParams();
            }
            return result;
        }
    }


    /**
     * Convenience method to reset the cached parameters to the current default values
     * if they are not persistent between calls to the service.
     */
    private void resetCachedParams() {
        mCachedParams[Engine.PARAM_POSITION_STREAM + 1] =
                String.valueOf(Engine.DEFAULT_STREAM);
        mCachedParams[Engine.PARAM_POSITION_UTTERANCE_ID+ 1] = "";
        mCachedParams[Engine.PARAM_POSITION_VOLUME + 1] = Engine.DEFAULT_VOLUME_STRING;
        mCachedParams[Engine.PARAM_POSITION_PAN + 1] = Engine.DEFAULT_PAN_STRING;
    }

    /**
     * Convenience method to save a parameter in the cached parameter array, at the given index,
     * for a property saved in the given hashmap.
     */
    private void setCachedParam(HashMap<String,String> params, String key, int keyIndex) {
        String extra = params.get(key);
        if (extra != null) {
            mCachedParams[keyIndex+1] = extra;
        }
    }

    /**
     * Sets the OnUtteranceCompletedListener that will fire when an utterance completes.
     *
     * @param listener
     *            The OnUtteranceCompletedListener
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int setOnUtteranceCompletedListener(
            final OnUtteranceCompletedListener listener) {
        synchronized (mStartLock) {
            int result = ERROR;
            if (!mStarted) {
                return result;
            }
            mITtscallback = new ITtsCallback.Stub() {
                public void utteranceCompleted(String utteranceId) throws RemoteException {
                    if (listener != null) {
                        listener.onUtteranceCompleted(utteranceId);
                    }
                }
            };
            try {
                result = mITts.registerCallback(mPackageName, mITtscallback);
            } catch (RemoteException e) {
                restart("registerCallback", e);
            } catch (NullPointerException e) {
                restart("registerCallback", e);
            } catch (IllegalStateException e) {
                restart("registerCallback", e);
            }
            return result;
        }
    }

    /**
     * Sets the speech synthesis engine to be used by its packagename.
     *
     * @param enginePackageName
     *            The packagename for the synthesis engine (ie, "com.svox.pico")
     *
     * @return Code indicating success or failure. See {@link #ERROR} and {@link #SUCCESS}.
     */
    public int setEngineByPackageName(String enginePackageName) {
        synchronized (mStartLock) {
            int result = TextToSpeech.ERROR;
            if (!mStarted) {
                return result;
            }
            try {
                result = mITts.setEngineByPackageName(enginePackageName);
                if (result == TextToSpeech.SUCCESS){
                    mCachedParams[Engine.PARAM_POSITION_ENGINE + 1] = enginePackageName;
                }
            } catch (RemoteException e) {
                restart("setEngineByPackageName", e);
            } catch (NullPointerException e) {
                restart("setEngineByPackageName", e);
            } catch (IllegalStateException e) {
                restart("setEngineByPackageName", e);
            }
            return result;
        }
    }


    /**
     * Gets the packagename of the default speech synthesis engine.
     *
     * @return Packagename of the TTS engine that the user has chosen as their default.
     */
    public String getDefaultEngine() {
        synchronized (mStartLock) {
            String engineName = "";
            if (!mStarted) {
                return engineName;
            }
            try {
                engineName = mITts.getDefaultEngine();
            } catch (RemoteException e) {
                restart("getDefaultEngine", e);
            } catch (NullPointerException e) {
                restart("getDefaultEngine", e);
            } catch (IllegalStateException e) {
                restart("getDefaultEngine", e);
            }
            return engineName;
        }
    }


    /**
     * Returns whether or not the user is forcing their defaults to override the
     * Text-To-Speech settings set by applications.
     *
     * @return Whether or not defaults are enforced.
     */
    public boolean areDefaultsEnforced() {
        synchronized (mStartLock) {
            boolean defaultsEnforced = false;
            if (!mStarted) {
                return defaultsEnforced;
            }
            try {
                defaultsEnforced = mITts.areDefaultsEnforced();
            } catch (RemoteException e) {
                restart("areDefaultsEnforced", e);
            } catch (NullPointerException e) {
                restart("areDefaultsEnforced", e);
            } catch (IllegalStateException e) {
                restart("areDefaultsEnforced", e);
            }
            return defaultsEnforced;
        }
    }

    /**
     * Restarts the TTS after a failure.
     */
    private void restart(String method, Exception e) {
        // TTS died; restart it.
        Log.e(TAG, method, e);
        mStarted = false;
        initTts();
    }
}