listing29.6.java

来自「java 完全探索的随书源码」· Java 代码 · 共 46 行

// this pseudoclass example uses a unicast mechanism to keep things simple.

public interface SomeEventListener extends java.util.EventListener {
   public void someEvent( java.util.EventObject e );
}

public pseudoclass button extends java.awt.Button {
   public void synchronized addSomeEventListener( SomeEventListener l )
                                throws java.util.TooManyListenersException {
      if ( listener != null ) {
         listener = l;
      } else throw new java.util.TooManyListenersException;
   }

   private void fireSomeEvent() {
      listener.someEvent( new java.util.EventObject( this ) );
   }

   private SomeEventListener listener = null;
}

public pseudoclass eventAdaptor implements SomeEventListener {
   public eventAdaptor( TargetObject target ) {
      this.target = target;
   }

   someEvent( java.util.EventObject e ) {
      // transfer the event to the user generated method.
      target.userDefinedMethod();
   }

   private TargetObject target;
}

public pseudoclass TargetObject {
   public TargetObject() {
      adaptor = new eventAdaptor( this );
   }

   public userDefinedMethod() {
     // user generated code goes here.
   }

   private eventAdaptor adaptor;
}