// FoundationApplet.java // By Ned Etcode // Copyright 1995, 1996 Netscape Communications Corp. All rights reserved. package netscape.application; import netscape.util.*; import java.applet.Applet; /** java.applet.Applet subclass that attaches a FoundationPanel instance * to the Java Applet. Each Application has a FoundationApplet * instance, although you will never access it directly. */ public class FoundationApplet extends Applet implements Runnable { static Hashtable groupToApplet = new Hashtable(1); Application application; FoundationPanel panel; boolean startedRun, appletStarted; private static Vector applicationStack; /// ddk - ADDED FOR JAVASCRIPT SUPPORT /** Constructs a new FoundationApplet. */ public FoundationApplet() { super(); } static void setAppletForGroup(FoundationApplet applet) { groupToApplet.put(Thread.currentThread().getThreadGroup(), applet); } static FoundationApplet applet() { ThreadGroup group = Thread.currentThread().getThreadGroup(); return (FoundationApplet)groupToApplet.get(group); } /** Sets the Applet's Application. */ public void setApplication(Application application) { this.application = application; } /** Returns the Applet's Application. * @see #setApplication */ public Application application() { return application; } /** Initializes the FoundationApplet instance. Also creates the * Application object and starts a new thread for it to run in. You * should never call this method. */ public void init() { Thread appThread = new Thread(this, "Main Application Thread"); super.init(); setAppletForGroup(this); // This lock is used to make sure that we don't return before the // application is set up enough to allow the processing of AWT events // that come in to the applet frame. run() unlocks it. appThread.start(); synchronized (this) { while (!startedRun) { try { wait(); } catch (InterruptedException e) { } } } } /** Creates the Application in the main Application thread. * You should never call this method. */ public void run() { String param = getParameter("ApplicationClass"); if (param != null && !param.equals("")) { Object newObject = instantiateObjectOfClass(param); if (newObject instanceof Application) { application = (Application)newObject; } else { throw new InconsistencyException("ApplicationClass " + param + " must be a subclass of netscape.application.Application"); } } else { throw new InconsistencyException("An ApplicationClass parameter must be specified in the tag. For example:\n\n \n\n"); } synchronized (this) { startedRun = true; // This notify will cause the applet's init routine to return. notifyAll(); // We don't run the event loop until the start() comes in. // This means we can draw to the applet's Graphics context. while (!appletStarted) { try { wait(); } catch (InterruptedException e) { } } } application.run(); } /** Starts the Applet. */ public void start() { synchronized (this) { ApplicationEvent event = new ApplicationEvent(); if (!appletStarted) { // If this is the first start for the applet, unlock the // run() call. appletStarted = true; notifyAll(); } event.type = ApplicationEvent.APPLET_STARTED; event.processor = application; application.eventLoop.addEvent(event); } } /** Stops the Applet. */ public void stop() { ApplicationEvent event = new ApplicationEvent(); event.type = ApplicationEvent.APPLET_STOPPED; event.processor = application; application.eventLoop.addEvent(event); } /** Destroys the Applet. */ public void destroy() { /* AWT Thread */ application.stopRunningForAWT(); super.destroy(); } void destroyFromIFC() { super.destroy(); } /** Cleanup resources associated with the Applet. * this is always called by the ifc main thread */ void cleanup() { // It would be nice to be able to post some application cleanup // notification to interested parties here. ALERT! Enumeration groups; FoundationApplet applet; ThreadGroup group; /* it would be nice to be able to post some application destroy * notification to interested parties here. ALERT! */ groups = groupToApplet.keys(); removeApplication(application); /// ddk - ADDED FOR JAVASCRIPT SUPPORT while (groups.hasMoreElements()) { group = (ThreadGroup)groups.nextElement(); applet = (FoundationApplet)groupToApplet.get(group); if (applet == this) { groupToApplet.remove(group); break; } } } /* Installs the FoundationCanvas in the Applet with the necessary * RootView. */ void setupCanvas(Application app) { int width, height; RootView rootView; application = app; width = size().width; height = size().height; panel = createPanel(); application.setMainRootView(panel.rootView()); panel.reshape(0, 0, width, height); add(panel); // Eventually we will support using a custom view as an alternative // to a custom application. Place a custom view (if specified) on the // rootView for the user. // if (defaultView != null) { // defaultView.init(0, 0, width, height); // rootView.addSubview(defaultView); // } // Eventually we will want to load an interface file here. ALERT! // loadInterface(getParameter("velocity")); } /** Overridden to properly layout the Applet. */ public void layout() { if (panel != null) { java.awt.Dimension size = size(); java.awt.Insets insets = insets(); int x = insets.left, y = insets.top, w = size.width - (insets.left + insets.right), h = size.height - (insets.top + insets.bottom); if (w > 0 && h > 0) { panel.reshape(x, y, w, h); } } } Object instantiateObjectOfClass(String className) { Class newClass; Object newObject; try { newClass = classForName(className); newObject = newClass.newInstance(); } catch (ClassNotFoundException e) { throw new InconsistencyException("Unable to find class \"" + className + "\""); } catch (InstantiationException e) { throw new InconsistencyException("Unable to instantiate class \"" + className + "\" -- " + e.getMessage()); } catch (IllegalAccessException e) { throw new InconsistencyException("Unable to instantiate class \"" + className + "\" -- " + e.getMessage()); } return newObject; } /** This method must be implemented by the Applet developer because * there is no way in the standard Java API for system classes (such as, * netscape.application) to look up an Applet's class by name. The * static method Class.forName() simply looks up one level in the * stack and gets the ClassLoader associated with the method block of the * caller. When the netscape.application classes are installed as * system classes, the ClassLoader is null. Thus, when code in * netscape.application calls Class.forName() it can only find * other system classes.

* The solution is an API that allows code to * find the ClassLoader for an applet by URL, and public API on * ClassLoader to ask it to load classes by name. Until these * enhancements can be made and distributed to all the world's Java * systems, Applets must subclass FoundationApplet and * implement the following one-line method: * 

      *     public abstract Class classForName(String className)
      *         throws ClassNotFoundException {
      *         return Class.forName(className);
      *     }
      *
*/ public Class classForName(String className) throws ClassNotFoundException { return Class.forName(className); } /** @private */ public void paint(java.awt.Graphics g) { super.paint(g); } /** Creates and returns the Applet's FoundationPanel. * FoundationApplet subclasses can override this method to provide a * custom FoundationPanel subclass. * @see FoundationPanel */ protected FoundationPanel createPanel() { return new FoundationPanel(); } /** Returns the FoundationPanel the Applet is using to display its * RootView. */ public FoundationPanel panel() { return panel; } /* This method will try to figure out if we are running in the Mozilla * thread. These values are valid for the Nav3.0/NavGold3.0 products. * Names appear valid on Sun and NT. This is also called in the EventLoop * before trying to setPriority to the thread. * * This method was removed to attempt to allow IE to call IFC stuff * properly. - ddk */ static boolean isMozillaThread(Thread aThread) { /// ddk - ADDED FOR JAVASCRIPT SUPPORT // ThreadGroup aThreadG = aThread.getThreadGroup(); // // return (aThread.getName().equals("main") // && aThreadG.getName().equals("main") // && aThreadG.getParent().getName().equals("system") // && aThreadG.getParent().getParent() == null); // return true; } /** Any JavaScript function that sends message to an IFC-based Applet must * call this method before sending any messages. Returns the Application. * The JavaScript function must generate a corresponding * popIFCContext() call. * This method placeds the Application object on a stack, so the IFC can * properly determine * which Application is running when the JavaScript method executes. * Failure to call popIFCContext() after the JavaScript finishes * may result in the Application not being properly garbage collected. * Here's a simple JavaScript example: * 
      *  <SCRIPT>
      *   function sendToFront() {
      *     SimpleDrawApp = document.applets[0].pushIFCContext();
      *     SimpleDrawApp.drawController.moveToFront();
      *     document.applets[0].popIFCContext();
      *   }
      *  </SCRIPT>
      *
* Note: This method can only be called from JavaScript * code. * @see #popIFCContext */ public Application pushIFCContext() { /// ddk - ADDED FOR JAVASCRIPT SUPPORT if(application == null) { return null; } if(!isMozillaThread(Thread.currentThread())) { throw new InconsistencyException( "pushIFCContext() must be called from JavaScript."); } if(applicationStack == null) { applicationStack = new Vector(); } applicationStack.addElement(application); return application; } /** Any JavaScript function that sends message to an IFC-based Applet must * call this method after sending all messages, to match the previous * pushIFCContext() call.

* Note: This method can only be called from JavaScript * code. * @see #pushIFCContext */ public void popIFCContext() { /// ddk - ADDED FOR JAVASCRIPT SUPPORT if(!isMozillaThread(Thread.currentThread())) { throw new InconsistencyException( "popIFCContext() must be called from JavaScript."); } if(applicationStack == null) { throw new InconsistencyException( "popIFCContext() called without ever calling pushIFCContext()"); } if(applicationStack.lastElement() != application) { throw new InconsistencyException("popIFCContext() attempted to pop " + applicationStack.lastElement() + " which was not itself:" + application); } if(applicationStack.removeLastElement() == null) { throw new InconsistencyException("extraneous popIFCContext() called without corresponding pushIFCContext()"); } } static Application currentApplication() { /// ddk - ADDED FOR JAVASCRIPT SUPPORT if(applicationStack == null) { return null; } return (Application)applicationStack.lastElement(); } static void removeApplication(Application app) { /// ddk - ADDED FOR JAVASCRIPT SUPPORT if(applicationStack == null) { return; } if(app == null) { return; } applicationStack.removeAll((Object)app); } }