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ScoreLabel.javaAPI DocExample3226Mon Apr 19 07:23:02 BST 2004javathreads.examples.ch03.example8

ScoreLabel

public class ScoreLabel extends JLabel implements CharacterListener

Fields Summary
private volatile int
score
private int
char2type
private CharacterSource
generator
private CharacterSource
typist
private Lock
adminLock
private Lock
charLock
private Lock
scoreLock
Constructors Summary
public ScoreLabel(CharacterSource generator, CharacterSource typist)



          
        this.generator = generator;
        this.typist = typist;

        if (generator != null)
            generator.addCharacterListener(this);
        if (typist != null)
             typist.addCharacterListener(this);
public ScoreLabel()

        this(null, null);
Methods Summary
public voidnewCharacter(CharacterEvent ce)

        try {
            scoreLock.lock();
            charLock.lock();
            // Previous character not typed correctly - 1 point penalty
            if (ce.source == generator) {
                if (char2type != -1) {
                    score--;
                    setScore();
                }
                char2type = ce.character;
            }

            // If character is extraneous - 1 point penalty
            // If character does not match - 1 point penalty
            else {
                if (char2type != ce.character) {
                    score--;
                } else {
                    score++;
                    char2type = -1;
                }
                setScore();
            }
        } finally {
            scoreLock.unlock();
            charLock.unlock();
        }
public voidresetGenerator(CharacterSource newGenerator)

        try {
            adminLock.lock();
            if (generator != null)
                generator.removeCharacterListener(this);

            generator = newGenerator;
            if (generator != null)
                generator.addCharacterListener(this);
        } finally {
            adminLock.unlock();
        }
public voidresetScore()

        try {
            charLock.lock();
            scoreLock.lock();
            score = 0;
            char2type = -1;
            setScore();
        } finally {
            charLock.unlock();
            scoreLock.unlock();
        }
public voidresetTypist(CharacterSource newTypist)

        try {
            adminLock.lock();
            if (typist != null)
                typist.removeCharacterListener(this);

            typist = newTypist;
            if (typist != null)
                typist.addCharacterListener(this);
        } finally {
            adminLock.unlock();
        }
private voidsetScore()

        // This method will be explained later in chapter 7
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                setText(Integer.toString(score));
            }
        });