Java example source code file (AppletViewerPanel.java)

This example Java source code file (AppletViewerPanel.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

appletcontext, appletpanel, appletviewerpanel, awt, hashtable, jar, malformedurlexception, net, network, string, throwable, url, util

The AppletViewerPanel.java Java example source code

/*
 * Copyright (c) 1995, 2005, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.applet;

import java.util.*;
import java.io.*;
import java.net.URL;
import java.net.MalformedURLException;
import java.awt.*;
import java.applet.*;
import sun.tools.jar.*;


/**
 * Sample applet panel class. The panel manages and manipulates the
 * applet as it is being loaded. It forks a seperate thread in a new
 * thread group to call the applet's init(), start(), stop(), and
 * destroy() methods.
 *
 * @author      Arthur van Hoff
 */
class AppletViewerPanel extends AppletPanel {

    /* Are we debugging? */
    static boolean debug = false;

    /**
     * The document url.
     */
    URL documentURL;

    /**
     * The base url.
     */
    URL baseURL;

    /**
     * The attributes of the applet.
     */
    Hashtable atts;

    /*
     * JDK 1.1 serialVersionUID
     */
    private static final long serialVersionUID = 8890989370785545619L;

    /**
     * Construct an applet viewer and start the applet.
     */
    AppletViewerPanel(URL documentURL, Hashtable atts) {
        this.documentURL = documentURL;
        this.atts = atts;

        String att = getParameter("codebase");
        if (att != null) {
            if (!att.endsWith("/")) {
                att += "/";
            }
            try {
                baseURL = new URL(documentURL, att);
            } catch (MalformedURLException e) {
            }
        }
        if (baseURL == null) {
            String file = documentURL.getFile();
            int i = file.lastIndexOf('/');
            if (i >= 0 && i < file.length() - 1) {
                try {
                    baseURL = new URL(documentURL, file.substring(0, i + 1));
                } catch (MalformedURLException e) {
                }
            }
        }

        // when all is said & done, baseURL shouldn't be null
        if (baseURL == null)
                baseURL = documentURL;


    }

    /**
     * Get an applet parameter.
     */
    public String getParameter(String name) {
        return (String)atts.get(name.toLowerCase());
    }

    /**
     * Get the document url.
     */
    public URL getDocumentBase() {
        return documentURL;

    }

    /**
     * Get the base url.
     */
    public URL getCodeBase() {
        return baseURL;
    }

    /**
     * Get the width.
     */
    public int getWidth() {
        String w = getParameter("width");
        if (w != null) {
            return Integer.valueOf(w).intValue();
        }
        return 0;
    }


    /**
     * Get the height.
     */
    public int getHeight() {
        String h = getParameter("height");
        if (h != null) {
            return Integer.valueOf(h).intValue();
        }
        return 0;
    }

    /**
     * Get initial_focus
     */
    public boolean hasInitialFocus()
    {

        // 6234219: Do not set initial focus on an applet
        // during startup if applet is targeted for
        // JDK 1.1/1.2. [stanley.ho]
        if (isJDK11Applet() || isJDK12Applet())
            return false;

        String initialFocus = getParameter("initial_focus");

        if (initialFocus != null)
        {
            if (initialFocus.toLowerCase().equals("false"))
                return false;
        }

        return true;
    }

    /**
     * Get the code parameter
     */
    public String getCode() {
        return getParameter("code");
    }


    /**
     * Return the list of jar files if specified.
     * Otherwise return null.
     */
    public String getJarFiles() {
        return getParameter("archive");
    }

    /**
     * Return the value of the object param
     */
    public String getSerializedObject() {
        return getParameter("object");// another name?
    }


    /**
     * Get the applet context. For now this is
     * also implemented by the AppletPanel class.
     */
    public AppletContext getAppletContext() {
        return (AppletContext)getParent();
    }

    static void debug(String s) {
        if(debug)
            System.err.println("AppletViewerPanel:::" + s);
    }

    static void debug(String s, Throwable t) {
        if(debug) {
            t.printStackTrace();
            debug(s);
        }
    }
}