public void newCharacter(CharacterEvent ce) {
int oldChar2type;
// Previous character not typed correctly - 1 point penalty
if (ce.source == generator.get()) {
oldChar2type = char2type.getAndSet(ce.character); // 接收随机字母
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()) {
// 在此有个假设：即正在使用的该变量值不会被变更且程序代码完成时也是如此
// 所有已经被我们设定的具有特定值的变量就应当是那个值。
while (true) {
oldChar2type = char2type.get(); // 获取上次已接收到的随机字母
if (oldChar2type != ce.character) { // ce.character是用户输入的字母，现在作比较
score.decrementAndGet();
break;
} else if (char2type.compareAndSet(oldChar2type, -1)) {
score.incrementAndGet();
break;
}
}
setScore();
}
}
public void resetTypist(CharacterSource newTypist) {
CharacterSource oldTypist;
if (newTypist != null) newTypist.addCharacterListener(this);
oldTypist = typist.getAndSet(newTypist);
if (oldTypist != null) oldTypist.removeCharacterListener(this);
}
public void resetGenerator(CharacterSource newGenerator) {
/** 注意这个方法的算法更改逻辑 */
CharacterSource oldGenerator;
if (newGenerator != null) newGenerator.addCharacterListener(this);
oldGenerator = generator.getAndSet(newGenerator);
if (oldGenerator != null) oldGenerator.removeCharacterListener(this);
}