SE450: Action Example [14/55] Previous pageContentsNext page

file:horstmann/ch10_command/CommandTester.java [source] [doc-public] [doc-private]
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package horstmann.ch10_command;
import java.awt.BorderLayout;

import javax.swing.Action;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JTextArea;
import javax.swing.JToolBar;

/**
   This program demonstrates action objects. Two actions
   insert greetings into a text area. Each action can be
   triggered by a menu item or toolbar button. When an
   action is carried out, the opposite action becomes enabled.
 */
public class CommandTester
{
  public static void main(String[] args)
  {
    JFrame frame = new JFrame();
    JMenuBar bar = new JMenuBar();
    frame.setJMenuBar(bar);
    JMenu menu = new JMenu("Say");
    bar.add(menu);
    JToolBar toolBar = new JToolBar();
    frame.add(toolBar, BorderLayout.NORTH);
    JTextArea textArea = new JTextArea(10, 40);
    frame.add(textArea, BorderLayout.CENTER);

    GreetingAction helloAction = new GreetingAction(
        "Hello, World", textArea);
    helloAction.putValue(Action.NAME, "Hello");
    helloAction.putValue(Action.SMALL_ICON,
        new ImageIcon("hello.png"));

    GreetingAction goodbyeAction = new GreetingAction(
        "Goodbye, World", textArea);
    goodbyeAction.putValue(Action.NAME, "Goodbye");
    goodbyeAction.putValue(Action.SMALL_ICON,
        new ImageIcon("goodbye.png"));

    helloAction.setOpposite(goodbyeAction);
    goodbyeAction.setOpposite(helloAction);
    goodbyeAction.setEnabled(false);

    menu.add(helloAction);
    menu.add(goodbyeAction);

    toolBar.add(helloAction);
    toolBar.add(goodbyeAction);

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
  }
}

file:horstmann/ch10_command/GreetingAction.java [source] [doc-public] [doc-private]
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package horstmann.ch10_command;
import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JTextArea;

/**
   This action places a greeting into a text field
   and afterwards disables itself and enables its
   opposite action.
 */
@SuppressWarnings("serial")
public class GreetingAction extends AbstractAction
{
  /**
      Constructs a greeting action.
      @param greeting the string to add to the text area
      @param textArea the text area to which to add the greeting
   */
  public GreetingAction(String greeting, JTextArea textArea)
  {
    this.greeting = greeting;
    this.textArea = textArea;
  }

  /**
      Sets the opposite action.
      @param action the action to be enabled after this action was
      carried out
   */
  public void setOpposite(Action action)
  {
    oppositeAction = action;
  }

  public void actionPerformed(ActionEvent event)
  {
    textArea.append(greeting);
    textArea.append("\n");
    if (oppositeAction != null)
    {
      setEnabled(false);
      oppositeAction.setEnabled(true);
    }
  }

  private String greeting;
  private JTextArea textArea;
  private Action oppositeAction;
}

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