Applet3Panel: Clarify ClassLoader role; Start Applet3Panel.loaderThread before Applet3Panel.handle (applet thread), joined at APPLET_INIT

2 files changed, 64 insertions, 50 deletions

diff --git a/netx/jogamp/applet/Applet3Panel.java b/netx/jogamp/applet/Applet3Panel.java
index 34d8d53..5acad4d 100644
--- a/netx/jogamp/applet/Applet3Panel.java
+++ b/netx/jogamp/applet/Applet3Panel.java
@@ -157,6 +157,10 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
      */
     protected Thread handler;
 
+    /**
+     * The thread to use during applet loading
+     */
+    protected volatile Thread loaderThread = null;
 
     /**
      * The initial applet size.
@@ -171,12 +175,6 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
     MessageUtils mu = new MessageUtils();
 
     /**
-     * The thread to use during applet loading
-     */
-
-    Thread loaderThread = null;
-
-    /**
      * Flag to indicate that a loading has been cancelled
      */
     boolean loadAbortRequest = false;
@@ -199,6 +197,23 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
      */
     final Hashtable<String, String> parameters;
 
+    /**
+     * Must be override with upstream plugin implementation, i.e. browser connection.
+     * Known implementations are {@link jogamp.plugin.applet.PluginApplet3Viewer} !
+     */
+    protected abstract Applet3Context getAppletContext();
+
+    /**
+     * Return true if implementing class provides it's own applet ClassLoader, otherwise false.
+     */
+    public abstract boolean  useCustomAppletClassLoader();
+
+    /**
+     * Implementing may provide it's own specific ClassLoader, see {@link #useCustomAppletClassLoader()}, otherwise null.
+     */
+    public abstract ClassLoader getAppletClassLoader();
+
+
     public Applet3Panel(long nativeWindowHandle, int width, int height, URL documentURL, Hashtable<String, String> parameters) {
         this.documentURL = documentURL;
         this.parameters = parameters;
@@ -310,12 +325,6 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
 
     public int getStatus() { return status; }
 
-    /**
-     * Must be override with upstream plugin implementation, i.e. browser connection.
-     * Known implementations are {@link jogamp.plugin.applet.PluginApplet3Viewer} !
-     */
-    protected abstract Applet3Context getAppletContext();
-
     //
     // Applet3Context
     //
@@ -698,6 +707,10 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
          }
      }
 
+     protected String getThreadName() {
+         return Thread.currentThread().getName();
+     }
+
     /**
      * Execute applet events.
      * Here is the state transition diagram
@@ -729,8 +742,13 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
      */
     @Override
     public void run() {
+        //  Applet Thread is Applet3Panel.handle
+        //    - Created via Applet3Panel, NetxApplet3Panel: createAppletThread()
+        //  Applet Loader Thread is Applet3Panel.loaderThread
+        //    - Created via Applet3Panel.run() on Applet Thread (Applet3Panel.handle)
+        //
 
-        Thread curThread = Thread.currentThread();
+        final Thread curThread = Thread.currentThread();
         if (curThread == loaderThread) {
             // if we are in the loader thread, cause
             // loading to occur.  We may exit this with
@@ -754,7 +772,7 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
             try {
                 switch (evt.getID()) {
                   case APPLET_LOAD:
-                      if (!okToLoad()) {
+                      if ( loadAbortRequested() ) {
                           break;
                       }
                       // This complexity allows loading of applets to be
@@ -768,20 +786,27 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
                       if (loaderThread == null) {
                           // REMIND: do we want a name?
                           //System.out.println("------------------- loading applet");
-                          setLoaderThread(new Thread(this));
+                          synchronized (Applet3Panel.this) {
+                              this.loaderThread = new Thread(this);
+                          }
                           loaderThread.start();
-                          // we get to go to sleep while this runs
-                          loaderThread.join();
-                          setLoaderThread(null);
                       } else {
-                          // REMIND: issue an error -- this case should never
-                          // occur.
+                          // We kick off loading thread before applet thread in NetxApplet3Panel - no Error
                       }
                       break;
 
                   case APPLET_INIT:
-                    // AppletViewer "Restart" will jump from destroy method to
-                    // init, that is why we need to check status w/ APPLET_DESTROY
+                      if (loaderThread != null) {
+                          // we get to go to sleep while this runs
+                          loaderThread.join();
+                          synchronized (Applet3Panel.this) {
+                              this.loaderThread = null;
+                          }
+                      } else {
+                          throw new InternalError("XXX loader Thread not set! "+getThreadName());
+                      }
+                      // AppletViewer "Restart" will jump from destroy method to
+                      // init, that is why we need to check status w/ APPLET_DESTROY
                       if (status != APPLET_LOAD && status != APPLET_DESTROY) {
                           showAppletStatus("notloaded");
                           break;
@@ -1104,8 +1129,8 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
     }
 
 
-    protected synchronized boolean okToLoad() {
-        return !loadAbortRequest;
+    protected synchronized boolean loadAbortRequested() {
+        return loadAbortRequest;
     }
 
     protected synchronized void clearLoadAbortRequest() {
@@ -1117,11 +1142,6 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
     }
 
 
-    private synchronized void setLoaderThread(Thread loaderThread) {
-        this.loaderThread = loaderThread;
-    }
-
-
     // FIXME private EventQueue appEvtQ = null;
 
     /**
@@ -1191,29 +1211,20 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
     }
 
     /**
-     * FIXME: Hack - Until knowing which CL to use .. via {@link #getClassLoader(URL, String)}.
+     * @see #useCustomAppletClassLoader()
+     * @see #getAppletClassLoader()
+     * @see #getClassLoader(URL, String)
      */
     private void setClassLoader() {
-        final ClassLoader _loader0 = getAppletClassLoader();
-        if( null != _loader0 ) {
-            loader = _loader0;
-            applet3Loader = null;
-        }
-        final ClassLoader _loader = getClassLoader(getCodeBase(), getClassLoaderCacheKey());
-        if( _loader instanceof Applet3ClassLoader ) {
-            applet3Loader = (Applet3ClassLoader)_loader;
+        if( useCustomAppletClassLoader() ) {
+            loader = getAppletClassLoader();
         } else {
-            applet3Loader = null;
+            applet3Loader = getClassLoader(getCodeBase(), getClassLoaderCacheKey());
+            loader = applet3Loader;
         }
-        loader = _loader;
     }
 
     /**
-     * Implementation may provide it's own specific ClassLoader, otherwise null.
-     */
-    public abstract ClassLoader getAppletClassLoader();
-
-    /**
      * This method actually creates an AppletClassLoader.
      *
      * It can be override by subclasses (such as the Plug-in)
@@ -1226,7 +1237,7 @@ public abstract class Applet3Panel implements Applet3Context, Runnable {
     /**
      * Get a class loader. Create in a restricted context
      */
-    synchronized ClassLoader getClassLoader(final URL codebase, final String key) {
+    private synchronized Applet3ClassLoader getClassLoader(final URL codebase, final String key) {
         Applet3ClassLoader c = classloaders.get(key);
         if (c == null) {
             final AccessControlContext acc = getAccessControlContext(codebase);
diff --git a/netx/jogamp/plugin/jnlp/NetxApplet3Panel.java b/netx/jogamp/plugin/jnlp/NetxApplet3Panel.java
index 875dc5a..0d79911 100644
--- a/netx/jogamp/plugin/jnlp/NetxApplet3Panel.java
+++ b/netx/jogamp/plugin/jnlp/NetxApplet3Panel.java
@@ -98,11 +98,8 @@ public class NetxApplet3Panel extends Applet3Panel implements SplashController {
         super.showAppletException(t);
     }
 
-    //Overriding to use Netx classloader. You might need to relax visibility
-    //in sun.applet.AppletPanel for runLoader().
     @Override
     protected void runLoader() {
-
         try {
             bridge = new PluginBridge(baseURL,
                                 getDocumentBase(),
@@ -158,8 +155,11 @@ public class NetxApplet3Panel extends Applet3Panel implements SplashController {
                 OutputController.getLogger().log("JNLPRuntime already initialized");
             }
         }
+        final ThreadGroup tg = getThreadGroup();
+        loaderThread = new Thread(tg, this, "NetxLoaderThread @ " + this.documentURL);
+        loaderThread.start();
 
-        handler = new Thread(getThreadGroup(), this, "NetxPanelThread@" + this.documentURL);
+        handler = new Thread(tg, this, "NetxPanelThread @ " + this.documentURL);
         handler.start();
     }
 
@@ -177,6 +177,9 @@ public class NetxApplet3Panel extends Applet3Panel implements SplashController {
     }
 
     @Override
+    public boolean  useCustomAppletClassLoader() { return true; }
+
+    @Override
     public ClassLoader getAppletClassLoader() {
         return appInst.getClassLoader();
     }