Page 167 - The Definitive Guide to Building Java Robots

Preston_5564C05.fm Page 148 Tuesday, September 20, 2005 5:13 AM

148 CHAPTER 5 ■ SPEECH

Code Objective

The objective here is to use the JNI native class to synthesize speech.

Code Discussion

This class has a static block that calls the QuadTTS.dll. This DLL must be in the path; I put it in
the c:\windows\system32 directory. The constructor is just a default QuadmoreTTS() and is
excluded from the source. I have the three methods from the native code at my disposal—
SpeakDarling(), setVoice(), and getVoiceToken()—but currently, I’m only using SpeakDarling().
See Example 5-8.

Example 5-8. QuadmoreTTS.java
package com.scottpreston.javarobot.chapter5;

public class QuadmoreTTS {

// this is a DLL in system path QuadTTS.dll
static {
System.loadLibrary("QuadTTS");
}

// native method
public native boolean SpeakDarling(String strInput);
// native method
public native boolean setVoiceToken(String s);
// native method
public native String getVoiceToken();

// sample program
public static void main(String args[]) {
QuadmoreTTS v = new QuadmoreTTS();
boolean result = v.SpeakDarling("Java Robots Are Cool!");
System.out.println("done!");
}
}

I could use the QuadmoreTTS class in my programs, but I decided to create a wrapper
class that implements the JVoice interface of my other text-to-speech classes.
There are two fields—one is the QuadmoreTTS class I created in the previous example,
and the other is a static instance of the MicrosoftVoice—because I only want one program at a
time accessing the voice synthesis engine.
Next, I implement the following methods from JVoice: open(), close(), and speak(). While
open() and close() do nothing, speak() calls the native class SpeakDarling() method. If there’s
an error from this class, I’ve thrown an exception.
The sample program, main(), says the same phrase done earlier in the last two speech
implementation classes. See Example 5-9.