同步与List

private List listeners = new ArrayList();

 

public void addCharacterListener(CharacterListener cl) {

  synchronized(listeners) {
      listeners.add(cl);
  }
} 

public void removeCharacterListener(CharacterListener cl) {
  synchronized(listeners) {
    listeners.remove(cl);
  }
}

public void fireNewCharacter(CharacterSource source, int c) {
    CharacterEvent ce = new CharacterEvent(source, c);
    CharacterListener[] cl;
    synchronized(listeners) {
        cl = (CharacterListener[])listeners.toArray(new CharacterListener[0]);
    }
    for(int i=0; i<cl.length; i++)
        cl[i].newCharacter(ce);
}