textreader.java

来自「java 完全探索的随书源码」· Java 代码 · 共 94 行

import java.awt.*;
import java.awt.event.*;
import java.beans.*;
public class TextReader extends TextField {
   // default constructor for this Bean.  This is the constructor that an
   // application builder (such aslike Visual Basic) would use.
   public TextReader() {
      this( "", 40 );
   }

   // custom constructor for this Bean.  This is the constructor that you
   // would likely use if you were doing your coding from scratch.
   public TextReader( String InputText, int Width ) {
      super( InputText, Width );
      this.InputText = InputText;
      this.Width = Width;
      setEditable( true );

      // update the InputText property when the enter key is
      // pressed within the TextField
      this.addActionListener( new ActionListener() {
        public void actionPerformed( ActionEvent e ) {
          setInputText(getText());
        }
      });
   }

   // this Bean's properties.
   protected String InputText;
   protected int Width;

   // getter method for the InputText property.
   public synchronized String getInputText() {
     return InputText;
   }

   // setter method for the InputText property.
   public synchronized void setInputText( String newText ) {
      String oldText = InputText;
      InputText = newText;
      setText( InputText );
      changeAgent.firePropertyChange( "inputText", new String( oldText ),
                                      new String( newText ) );
   }

   // these two methods allow this Bean to have bound properties.
   public void addPropertyChangeListener( PropertyChangeListener l ) {
      changeAgent.addPropertyChangeListener( l );
   }

   public void removePropertyChangeListener( PropertyChangeListener l ) {
      changeAgent.removePropertyChangeListener( l );
   }

   protected PropertyChangeSupport changeAgent =
     new PropertyChangeSupport( this );

  // 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 );

}