/* * Copyright (c) 2000 David Flanagan.  All rights reserved. * This code is from the book Java Examples in a Nutshell, 2nd Edition. * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied. * You may study, use, and modify it for any non-commercial purpose. * You may distribute it non-commercially as long as you retain this notice. * For a commercial use license, or to purchase the book (recommended), * visit http://www.davidflanagan.com/javaexamples2. */package com.davidflanagan.examples.gui;import java.awt.*;                 // LayoutManager stuffimport javax.swing.*;              // Swing componentsimport java.awt.event.*;           // AWT event handlersimport javax.swing.event.*;        // Swing event handlersimport java.beans.*;               // JavaBeans event handlersimport java.awt.print.*;           // Printing functionalityimport java.io.*;                  // Input/outputimport java.net.*;                 // Networking with URLsimport java.util.*;                // Hashtables and other utilities// Import this class by name.  JFileChooser uses it, and its name conflicts// with java.io.FileFilterimport javax.swing.filechooser.FileFilter;  // Import a class for printing Swing documents.  See printing chapter.import com.davidflanagan.examples.print.PrintableDocument;/** * This class implements a simple web browser using the HTML * display capabilities of the JEditorPane component. **/public class WebBrowser extends JFrame    implements HyperlinkListener, PropertyChangeListener{    /**     * A simple main() method that allows the WebBrowser class to be used     * as a stand-alone application.     **/    public static void main(String[] args) throws IOException {	// End the program when there are no more open browser windows	WebBrowser.setExitWhenLastWindowClosed(true);	WebBrowser browser = new WebBrowser();  // Create a browser window	browser.setSize(800, 600);              // Set its size	browser.setVisible(true);               // Make it visible.	// Tell the browser what to display.  This method is defined below.	browser.displayPage((args.length > 0) ? args[0] : browser.getHome());    }        // This class uses GUIResourceBundle to create its menubar and toolbar    // This static initializer performs one-time registration of the    // required ResourceParser classes.    static {	GUIResourceBundle.registerResourceParser(new MenuBarParser());	GUIResourceBundle.registerResourceParser(new MenuParser());	GUIResourceBundle.registerResourceParser(new ActionParser());	GUIResourceBundle.registerResourceParser(new CommandParser());	GUIResourceBundle.registerResourceParser(new ToolBarParser());    }    // These are the Swing components that the browser uses    JEditorPane textPane;      // Where the HTML is displayed    JLabel messageLine;        // Displays one-line messages    JTextField urlField;       // Displays and edits the current URL    JFileChooser fileChooser;  // Allows the user to select a local file    // These are Actions that are used in the menubar and toolbar.    // We obtain explicit references to them from the GUIResourceBundle    // so we can enable and disable them.    Action backAction, forwardAction;    // These fields are used to maintain the browsing history of the window    java.util.List history = new ArrayList();  // The history list    int currentHistoryPage = -1;               // Current location in it    public static final int MAX_HISTORY = 50;  // Trim list when over this size    // These static fields control the behavior of the close() action    static int numBrowserWindows = 0;    static boolean exitWhenLastWindowClosed = false;    // This is where the "home()" method takes us.  See also setHome()    String home = "http://www.davidflanagan.com";  // A default value    /** Create and initialize a new WebBrowser window */    public WebBrowser() {	super();                          // Chain to JFrame constructor	textPane = new JEditorPane();     // Create HTML window	textPane.setEditable(false);      // Don't allow the user to edit it	// Register action listeners.  The first is to handle hyperlinks.	// The second is to receive property change notifications, which tell	// us when a document is done loading.  This class implements these	// EventListener interfaces, and the methods are defined below	textPane.addHyperlinkListener(this); 	textPane.addPropertyChangeListener(this);	// Put the text pane in a JScrollPane in the center of the window	this.getContentPane().add(new JScrollPane(textPane),				  BorderLayout.CENTER);	// Now create a message line and place it at the bottom of the window	messageLine = new JLabel(" ");	this.getContentPane().add(messageLine, BorderLayout.SOUTH);	// Read the file WebBrowserResources.properties (and any localized	// variants appropriate for the current Locale) to create a	// GUIResourceBundle from which we'll get our menubar and toolbar.	GUIResourceBundle resources =	    new GUIResourceBundle(this,"com.davidflanagan.examples.gui." +				  "WebBrowserResources");	// Read a menubar from the resource bundle and display it	JMenuBar menubar = (JMenuBar) resources.getResource("menubar",							    JMenuBar.class);	this.setJMenuBar(menubar);	// Read a toolbar from the resource bundle.  Don't display it yet.	JToolBar toolbar = 	    (JToolBar) resources.getResource("toolbar", JToolBar.class);	// Create a text field that the user can enter a URL in.	// Set up an action listener to respond to the ENTER key in that field	urlField = new JTextField();	urlField.addActionListener(new ActionListener() {		public void actionPerformed(ActionEvent e) {		    displayPage(urlField.getText());		}	    });	// Add the URL field and a label for it to the end of the toolbar	toolbar.add(new JLabel("         URL:"));	toolbar.add(urlField);	// And add the toolbar to the top of the window	this.getContentPane().add(toolbar, BorderLayout.NORTH);	// Read cached copies of two Action objects from the resource bundle	// These actions are used by the menubar and toolbar, and enabling and	// disabling them enables and disables the menu and toolbar items.	backAction = (Action)resources.getResource("action.back",Action.class);	forwardAction =	    (Action)resources.getResource("action.forward", Action.class);	// Start off with both actions disabled	backAction.setEnabled(false);	forwardAction.setEnabled(false);		// Create a ThemeManager for this frame, 	// and add a Theme menu to the menubar	ThemeManager themes = new ThemeManager(this, resources);	menubar.add(themes.getThemeMenu());	// Keep track of how many web browser windows are open	WebBrowser.numBrowserWindows++;    }    /** Set the static property that controls the behavior of close() */    public static void setExitWhenLastWindowClosed(boolean b) {	exitWhenLastWindowClosed = b;    }    /** These are accessor methods for the home property. */    public void setHome(String home) { this.home = home; }    public String getHome() { return home; }    /**     * This internal method attempts to load and display the specified URL.     * It is called from various places throughout the class.     **/    boolean visit(URL url) {	try {	    String href = url.toString();	    // Start animating.  Animation is stopped in propertyChanged()	    startAnimation("Loading " + href + "...");  	    textPane.setPage(url);   // Load and display the URL 	    this.setTitle(href);     // Display URL in window titlebar	    urlField.setText(href);  // Display URL in text input field	    return true;             // Return success	}	catch (IOException ex) {     // If page loading fails	    stopAnimation();	    messageLine.setText("Can't load page: " + ex.getMessage());	    return false;            // Return failure	}    }    /**     * Ask the browser to display the specified URL, and put it in the     * history list.     **/    public void displayPage(URL url) {	if (visit(url)) {    // go to the specified url, and if we succeed:	    history.add(url);       // Add the url to the history list	    int numentries = history.size();	    if (numentries > MAX_HISTORY+10) {  // Trim history when too large		history = history.subList(numentries-MAX_HISTORY, numentries);		numentries = MAX_HISTORY;	    }	    currentHistoryPage = numentries-1;  // Set current history page