Swing and threads - An Introduction to Graphical User Interfaces with Java Swing - page 239

(a) (b)

Figure 20.1 The results of applications (a) BlockingFrame and (b) NonBlockingFrame

the GUI appears to be blocked. The console output commands are operations that
do not require any graphical components and are not put into the event queue.
Therefore they are performed right away and appear as expected. The code for
BlockingFrame is listed below and the resulting display is shown in Figure 20.1.

File: its/Blocking/BlockingFrame.java

package its.Blocking; 1.

2.
3.

import its.SimpleFrame.SimpleFrame;

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import java.awt.event.ActionEvent;

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import java.awt.event.ActionListener;

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import javax.swing.JLabel;

7.

import javax.swing.JMenu;

8.

import javax.swing.JMenuBar;

9.

import javax.swing.JMenuItem;

10.
11.

public class BlockingFrame extends SimpleFrame

12.

{

13.
14.

private JLabel display;

15.
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public BlockingFrame(){

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display = new JLabel("Nothing happened");

this .getContentPane().add(display); 18.

19.
20.

JMenuBar menuBar = new JMenuBar();

this .setJMenuBar(menuBar); 21.

JMenu menu = new JMenu("Menu1"); 22.

menuBar.add(menu); 23.

JMenuItem startItem = new JMenuItem("Start"); 24.