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ScoreLabel.javaAPI DocExample3015Mon Apr 05 13:09:26 BST 2004javathreads.examples.ch05.example1

ScoreLabel

public class ScoreLabel extends JLabel implements CharacterListener

Fields Summary
private AtomicInteger
score
private AtomicInteger
char2type
private AtomicReference
generator
private AtomicReference
typist
Constructors Summary
public ScoreLabel(CharacterSource generator, CharacterSource typist)


          
        this.generator = new AtomicReference(generator);
        this.typist = new AtomicReference(typist);

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

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

        int oldChar2type;
 
        // Previous character not typed correctly - 1 point penalty
        if (ce.source == generator.get()) {
            oldChar2type = char2type.getAndSet(ce.character);

            if (oldChar2type != -1) {
                score.decrementAndGet();
                setScore();
            }
        }
        // If character is extraneous - 1 point penalty
        // If character does not match - 1 point penalty
        else if (ce.source == typist.get()) {
            while (true) {
                oldChar2type = char2type.get();

                if (oldChar2type != ce.character) {
                    score.decrementAndGet();
                    break;
                } else if (char2type.compareAndSet(oldChar2type, -1)) {
                    score.incrementAndGet();
                    break;
                }
            }

            setScore();
        }
public voidresetGenerator(CharacterSource newGenerator)

        CharacterSource oldGenerator;

        if (newGenerator != null)
            newGenerator.addCharacterListener(this);

        oldGenerator = generator.getAndSet(newGenerator);
        if (oldGenerator != null)
            oldGenerator.removeCharacterListener(this);
public voidresetScore()

        score.set(0);
        char2type.set(-1);
        setScore();
public voidresetTypist(CharacterSource newTypist)

        CharacterSource oldTypist;

        if (newTypist != null)
            newTypist.addCharacterListener(this);

        oldTypist = typist.getAndSet(newTypist);
        if (oldTypist != null)
            oldTypist.removeCharacterListener(this);
private voidsetScore()

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