j3dutils: add workaround for appcontext bug in Java 7 u251.6.0-pre9

As explained here:
http://stackoverflow.com/questions/17223304/appcontext-is-null-from-rmi-thread-with-java-7-update-25

Signed-off-by: Harvey Harrison <[email protected]>

1 files changed, 54 insertions, 2 deletions

diff --git a/src/classes/share/com/sun/j3d/exp/swing/JCanvas3D.java b/src/classes/share/com/sun/j3d/exp/swing/JCanvas3D.java
index c3301a9..feee512 100644
--- a/src/classes/share/com/sun/j3d/exp/swing/JCanvas3D.java
+++ b/src/classes/share/com/sun/j3d/exp/swing/JCanvas3D.java
@@ -56,6 +56,11 @@ import javax.swing.event.AncestorListener;
 
 import com.sun.j3d.exp.swing.impl.AutoOffScreenCanvas3D;
 
+// EP
+import java.lang.reflect.Field;
+import java.util.Map;
+// EP
+
 
 /**
  * This class provides a lightweight capability to Java 3D. The component
@@ -608,7 +613,7 @@ public class JCanvas3D extends JPanel implements AncestorListener {
         // to wait for the readback of the off-screen buffer to complete.
         // The total time is MAX_WAIT_LOOPS * MAX_WAIT_TIME msec.
         private static final int MAX_WAIT_LOOPS = 5;
-        private static final long MAX_WAIT_TIME = 100;
+        private static final long MAX_WAIT_TIME = 10; // EP: Used to be 100;
 
         /**
          * the bufferedImage that will be displayed as the result
@@ -659,6 +664,10 @@ public class JCanvas3D extends JPanel implements AncestorListener {
          */
         boolean waitingForSwap;
 
+        // EP
+        Object mainThreadContext;
+        // EP
+        
         /**
          * Creates a new instance of JCanvas3D. Resize mode is set
          * to RESIZE_IMMEDIATELY and validation delay to 100ms.
@@ -674,6 +683,15 @@ public class JCanvas3D extends JPanel implements AncestorListener {
             imageReadyBis = false;
             waitingForSwap = false;
             addNotifyFlag = false;
+            
+            // EP
+            try {
+              // Retrieve main thread AppContext instance by reflection 
+              this.mainThreadContext = Class.forName("sun.awt.AppContext").getMethod("getAppContext").invoke(null);
+            } catch (Throwable ex) {
+              // Let's consider app context is not necessary for the program
+            }
+            // EP
         }
 
         /**
@@ -728,6 +746,11 @@ public class JCanvas3D extends JPanel implements AncestorListener {
 
                 if (false == waitingForSwap) {
                     //                    System.err.println("repaint " + System.currentTimeMillis());
+                    
+                    // EP
+                    checkAppContext();
+                    // EP
+                    
                     this.lwCanvas.repaint();
                 } else {
                     notify();
@@ -737,6 +760,33 @@ public class JCanvas3D extends JPanel implements AncestorListener {
             }
         }
 
+        // EP
+        /**
+         * Checks that app context is correct.
+         */
+        private void checkAppContext() {
+          if (this.mainThreadContext != null) {
+            try {
+              // Check by reflection that sun.awt.AppContext.getAppContext() doesn't return null 
+              // (required by ImageIO.write() and other JMF internal calls) to apply workaround proposed at 
+              // http://stackoverflow.com/questions/17223304/appcontext-is-null-from-rmi-thread-with-java-7-update-25
+              Class<?> appContextClass = Class.forName("sun.awt.AppContext");
+              if (appContextClass.getMethod("getAppContext").invoke(null) == null) {
+                Field field = appContextClass.getDeclaredField("threadGroup2appContext");
+                field.setAccessible(true);
+                Map threadGroup2appContext = (Map)field.get(null);
+                ThreadGroup currentThreadGroup = Thread.currentThread().getThreadGroup();
+                threadGroup2appContext.put(currentThreadGroup, this.mainThreadContext);        
+              }
+            } catch (Throwable ex) {
+              // Let's consider app context is not necessary for the program
+            }
+            // Don't need mainThreadContext anymore
+            this.mainThreadContext = null;
+          }
+        }
+        // EP
+
         /**
          * Overriden so that the JComponent can access it.
          *
@@ -822,7 +872,9 @@ public class JCanvas3D extends JPanel implements AncestorListener {
 
                     if (!imageReadyBis && --counter <= 0) {
                         //if i've waited too long for the canvas to be there, let us declare it crashed.
-                        System.err.println("CANVAS CRASHED!!!");
+                        // EP
+                        // System.err.println("CANVAS CRASHED!!!");
+                        // EP
                         canvasCrashed = true;
                         return;
                     }