sender.java

来自「java applet编程,实现对相关图片声音的调用」· Java 代码 · 共 96 行

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Enumeration;

public class Sender extends Applet implements ActionListener
{
    private String myName;
    private TextField nameField;
    private TextArea status;
    private String newline;

    public void init()
	{
        setLayout( new BorderLayout() );

        Panel p;
		p = new Panel();

        Label receiverLabel = new Label("Receiver name:", Label.RIGHT);
        p.add(receiverLabel);

        nameField = new TextField(getParameter("receiverName"), 10);
        nameField.addActionListener(this);
        p.add(nameField);

        Button button = new Button("Send message");
        button.addActionListener(this);
        p.add(button);

		add(p, "North");

        status = new TextArea(5, 60);
        status.setEditable(false);
        add(status, "Center");

        myName = getParameter("myU");
        Label senderLabel = new Label("(My name is " + myName + ".)", Label.CENTER);
        add(senderLabel, "South");

		newline = System.getProperty("line.separator");
    }

    public void actionPerformed(ActionEvent event)
	{
        Applet receiver = null;
        String receiverName = nameField.getText(); //Get name to 
                                                   //search for.
        receiver = getAppletContext().getApplet(receiverName);
        if (receiver != null)
		{
            //Use the instanceof operator to make sure the applet
            //we found is a Receiver object.
            if (!(receiver instanceof Receiver))
			{
                status.append("Found applet named "
                              + receiverName + ", "
                              + "but it's not a Receiver object."
						      + newline);
            }
			else
			{
                status.append("Found applet named "
                              + receiverName + newline
                              + "  Sending message to it."
						      + newline);
                //Cast the receiver to be a Receiver object
                //(instead of just an Applet object) so that the
                //compiler will let us call a Receiver method.
                ((Receiver)receiver).processRequestFrom(myName);
            }
        }
		else
		{
            status.append("Couldn't find any applet named "
                          + receiverName + "." + newline);
        }
    }

    public Insets getInsets()
	{
        return new Insets(3,3,3,3);
    }

    public void paint(Graphics g)
	{
        g.drawRect(0, 0, 
                   getSize().width - 1, getSize().height - 1);
    }

    public String getAppletInfo()
	{
        return "Applet Sender by lyw.";
    }
}