j3dcore: cannot lock an object using its own reference

When updating the orientTransforms array reference, you cannot lock the update
using the same ref, as the next thread in will lock the new object and concurrently
run with the original updater.

Pointed out by findbugs.

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

1 files changed, 15 insertions, 18 deletions

diff --git a/src/classes/share/javax/media/j3d/OrientedShape3DRetained.java b/src/classes/share/javax/media/j3d/OrientedShape3DRetained.java
index 5bdf87c..4fe4026 100644
--- a/src/classes/share/javax/media/j3d/OrientedShape3DRetained.java
+++ b/src/classes/share/javax/media/j3d/OrientedShape3DRetained.java
@@ -83,7 +83,8 @@ class OrientedShape3DRetained extends Shape3DRetained {
 
     boolean orientedTransformDirty = true;
 
-    Transform3D[] orientedTransforms = new Transform3D[1];
+    private final Object transformLock = new Object();
+    private Transform3D[] orientedTransforms = new Transform3D[1];
     static final double EPSILON = 1.0e-6;
 
 
@@ -308,25 +309,21 @@ class OrientedShape3DRetained extends Shape3DRetained {
     }
 
 
-    Transform3D getOrientedTransform(int viewIndex) {
-	synchronized(orientedTransforms) {
-	    if (viewIndex >= orientedTransforms.length) {
-		Transform3D xform = new Transform3D();
-		Transform3D[] newList = new Transform3D[viewIndex+1];
-		for (int i = 0; i < orientedTransforms.length; i++) {
-		    newList[i] = orientedTransforms[i];
-		}
-		newList[viewIndex] = xform;
-		orientedTransforms = newList;
-	    }
-	    else {
-		if (orientedTransforms[viewIndex] == null) {
-		    orientedTransforms[viewIndex] = new Transform3D();
+	Transform3D getOrientedTransform(int viewIndex) {
+		synchronized (transformLock) {
+			// check if the transforms list needs to be expanded
+			if (viewIndex >= orientedTransforms.length) {
+				Transform3D[] newList = new Transform3D[viewIndex + 1];
+				System.arraycopy(orientedTransforms, 0, newList, 0, orientedTransforms.length);
+				orientedTransforms = newList;
+			}
+
+			if (orientedTransforms[viewIndex] == null)
+				orientedTransforms[viewIndex] = new Transform3D();
+
+			return orientedTransforms[viewIndex];
 		}
-	    }
 	}
-	return orientedTransforms[viewIndex];
-    }
 
     // called on the parent object
     // Should be synchronized so that the user thread does not modify the