listing29.5.java

来自「java 完全探索的随书源码」· Java 代码 · 共 36 行

   // setter method for the Columns property.
   public synchronized void setWidth( int newWidth )
   throws PropertyVetoException {
      int oldWidth = Width;
      vetoAgent.fireVetoableChange( "width", new Integer( oldWidth ),
                                    new Integer( newWidth ) );
      // no one vetoed, so change the property.
      Width = newWidth;
      setColumns( Width );
      Component p = getParent();
      if ( p != null ) {
         p.invalidate();
         p.doLayout();
      }
      changeAgent.firePropertyChange( "width", new Integer( oldWidth ),
                                      new Integer( newWidth ) );
   }

   // getter method for the Columns property.
   public synchronized int getWidth() {
      return Width;
   }

   // these two methods allow this Bean to have constrained properties.
   public void addVetoableChangeListener( VetoableChangeListener l ) {
      vetoAgent.addVetoableChangeListener( l );
   }

   public void removeVetoableChangeListener( VetoableChangeListener l ) {
      vetoAgent.removeVetoableChangeListener( l );
   }

   protected VetoableChangeSupport vetoAgent = 
     new VetoableChangeSupport( this );