java设计模式(2)--观察者模式Swing 多线程事件处理进度条和Observer的一个具体应用

适合使用环境: 当自身发生改变时，通知其它对象，其他对象会跟着改变。例如：swing中分页的程序，当你点击上一页下一页时需要重新激发事件，从数据库获得新数据时，等。

Swing的事件处理中，对于非常费时的处理如果不用多线程会造成主界面的阻塞，即界面一片白色，这样非常不好的，也是不提倡的，而起用多线程进行事件 处理又面临一个问题即如果通知用户事件处理的进度，是否处理完成，所以最好在处理的过程中给用户一提示，标明处理的进度信息。这种提示可以用进度条的信息 来表示出来，以下就是一个用进度条来标示事件进度的一个简单实例，这个例子中还使用了Observer模式
进度窗口：
package pro;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Observable;
import java.util.Observer;

import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JProgressBar;

public class Progress extends javax.swing.JDialog implements ActionListener {
    /**
     *
     */
    private static final long serialVersionUID = 1L;

    private JProgressBar pro_JPB;

    private JPanel btn_JP;

    private JButton cancel_JB;

    private JLabel show_JL;

    NewJFrame jf;

    public Progress(NewJFrame frame) {
        super(frame, true);
        this.jf = frame;
        initGUI();
    }

    set se = new set();

    private void initGUI() {
        try {

            se.addObserver(new setObserver());
            BorderLayout thisLayout = new BorderLayout();
            getContentPane().setLayout(thisLayout);
            {
                show_JL = new JLabel();
                getContentPane().add(show_JL, BorderLayout.NORTH);
                show_JL.setPreferredSize(new java.awt.Dimension(354, 22));
            }
            {
                pro_JPB = new JProgressBar();
                pro_JPB.setMinimum(0);
                pro_JPB.setMaximum(100);
                getContentPane().add(pro_JPB, BorderLayout.CENTER);
                pro_JPB.setPreferredSize(new java.awt.Dimension(392, 27));
            }
            {
                btn_JP = new JPanel();
                getContentPane().add(btn_JP, BorderLayout.SOUTH);
                {
                    cancel_JB = new JButton();
                    btn_JP.add(cancel_JB);
                    cancel_JB.setText(""u53d6"u6d88");
                    cancel_JB.addActionListener(this);
                }
            }
            this.setBackground(Color.DARK_GRAY.brighter());
            this.setUndecorated(true);
            this.setSize(392, 90);
            this.setLocationRelativeTo(null);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void setMinmum(int i) {
        pro_JPB.setMinimum(i);
    }

    public void setMaxmem(int i) {
        pro_JPB.setMaximum(i);
    }

    public void setVal(int i) {
        se.setPrice(i);
    }

    /**
     *
     * set Class->function:观察者模式的具体应用
     * 2007-4-17
     */
    class set extends Observable {
        private int price;

        public int getPrice() {
            return price;
        }

        public void setPrice(int price) {
            this.price = price;
            setChanged();
            notifyObservers(new Integer(price));
        }

    }

    class setObserver implements Observer {
        public void update(Observable obj, Object arg) {
            if (arg instanceof Integer) {
                int i = ((Integer) arg).intValue();
                pro_JPB.setValue(i);
                show_JL.setText((i - pro_JPB.getMinimum()) * 100
                        / (float) (pro_JPB.getMaximum() - pro_JPB.getMinimum())
                        + "%");
            }
        }

    }

    public void actionPerformed(ActionEvent e) {
        jf.setTh_Flag(false);
        this.setVisible(false);
    }

}

主程序：
package pro;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.WindowConstants;

public class NewJFrame extends javax.swing.JFrame {
    /**
     *
     */
    private static final long serialVersionUID = 1L;

    private JPanel cen_JP;

    private JButton jb;

    public static void main(String[] args) {
        NewJFrame inst = new NewJFrame();
        inst.setVisible(true);
    }

    public NewJFrame() {
        super();
        initGUI();
    }

    Progress pro;

    private void initGUI() {
        try {
            setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
            {
                cen_JP = new JPanel();
                getContentPane().add(cen_JP, BorderLayout.CENTER);
                {
                    jb = new JButton();
                    cen_JP.add(jb);
                    jb.setText("jButton1");
                    jbAction ja = new jbAction();
                    pro = new Progress(this);
                    jb.addActionListener(ja);
                }
            }
            pack();
            setSize(400, 300);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    boolean th_Flag = true;

    class jbAction implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            pro.setMaxmem(100);
            pro.setMinmum(0);
            new Thread() {
                public void run() {
                    for (int i = 1; i < 100; i++) {
                        if (!isTh_Flag()) {
                            setTh_Flag(true);

                            break;
                        }
                        try {
                            Thread.sleep(1000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        pro.setVal(i);
                        System.out.println("===" + i);
                    }
                }
            }.start();
            pro.setVal(0);
            pro.setVisible(true);
        }

    }

    public boolean isTh_Flag() {
        return th_Flag;
    }

    public void setTh_Flag(boolean th_Flag) {
        this.th_Flag = th_Flag;
    }
}