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Chapter 17 Using Applets As Servlet Front Ends

Listing 17.1 SearchApplet.java 

import java.applet.Applet;

import java.awt.*;

import java.awt.event.*;

import java.net.*;

import coreservlets.SearchSpec;

/** An applet that reads a value from a TextField,

 *  then uses it to build three distinct URLs with embedded

 *  GET data: one each for Google, Infoseek, and Lycos.

 *  The browser is directed to retrieve each of these

 *  URLs, displaying them in side by side frame cells.

 *  Note that standard HTML forms cannot automatically

 *  perform multiple submissions in this manner.

 */

public class SearchApplet extends Applet

                          implements ActionListener {

  private TextField queryField;

  private Button submitButton;

  public void init() {

    setFont(new Font("Serif", Font.BOLD, 18));

    add(new Label("Search String:"));

    queryField = new TextField(40);

    queryField.addActionListener(this);

    add(queryField);

    submitButton = new Button("Send to Search Engines");

    submitButton.addActionListener(this);

    add(submitButton);

  }

  /** Submit data when button is pressed or

   *  user presses Return in the TextField.

   */

  public void actionPerformed(ActionEvent event) {

    String query = URLEncoder.encode(queryField.getText());

    SearchSpec[] commonSpecs = SearchSpec.getCommonSpecs();

    // Omitting HotBot (last entry), as they use JavaScript to

    // pop result to top level frame. Thus the length 1 below.

    for(int i=0; i