svn commit: r1782293 - /sis/branches/JDK8/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/ContextualParameters.java

[desruisseaux]

Author: desruisseaux
Date: Thu Feb  9 06:10:25 2017
New Revision: 1782293

URL: http://svn.apache.org/viewvc?rev=1782293&view=rev
Log:
Fix a dead-lock between ContextualParameters and WeakHashSet (SIS-349).

Modified:
    
sis/branches/JDK8/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/ContextualParameters.java

Modified: 
sis/branches/JDK8/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/ContextualParameters.java
URL: 
http://svn.apache.org/viewvc/sis/branches/JDK8/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/ContextualParameters.java?rev=1782293&r1=1782292&r2=1782293&view=diff
==============================================================================
--- 
sis/branches/JDK8/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/ContextualParameters.java
 [UTF-8] (original)
+++ 
sis/branches/JDK8/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/ContextualParameters.java
 [UTF-8] Thu Feb  9 06:10:25 2017
@@ -127,7 +127,7 @@ import static org.apache.sis.util.Argume
  *
  * @author  Martin Desruisseaux (Geomatys)
  * @since   0.6
- * @version 0.7
+ * @version 0.8
  * @module
  *
  * @see org.apache.sis.referencing.operation.projection.NormalizedProjection
@@ -501,24 +501,33 @@ public class ContextualParameters extend
      *
      * @see 
org.apache.sis.referencing.operation.projection.NormalizedProjection#createMapProjection(MathTransformFactory)
      */
-    public synchronized MathTransform completeTransform(final 
MathTransformFactory factory, final MathTransform kernel)
+    public MathTransform completeTransform(final MathTransformFactory factory, 
final MathTransform kernel)
             throws FactoryException
     {
-        if (!isFrozen) {
-            freeze();
+        final MathTransform n, d;
+        synchronized (this) {
+            if (!isFrozen) {
+                freeze();
+            }
+            /*
+             * Creates the ConcatenatedTransform, letting the factory returns 
the cached instance
+             * if the caller already invoked this method previously (which 
usually do not happen).
+             */
+            n = factory.createAffineTransform(normalize);
+            d = factory.createAffineTransform(denormalize);
+            Matrix m;
+            if ((m = MathTransforms.getMatrix(n)) != null)   normalize = m;
+            if ((m = MathTransforms.getMatrix(d)) != null) denormalize = m;
         }
-        /*
-         * Creates the ConcatenatedTransform, letting the factory returns the 
cached instance
-         * if the caller already invoked this method previously (which usually 
do not happen).
-         */
-        final MathTransform n = factory.createAffineTransform(normalize);
-        final MathTransform d = factory.createAffineTransform(denormalize);
-        Matrix m;
-        if ((m = MathTransforms.getMatrix(n)) != null)   normalize = m;
-        if ((m = MathTransforms.getMatrix(d)) != null) denormalize = m;
         if (kernel == null) {   // Undocumented feature useful for 
MolodenskyTransform constructor.
             return null;
         }
+        /*
+         * Following call must be outside the synchronized block for avoiding 
dead-lock. This is because the
+         * factory typically contains a WeakHashSet, which invoke in turn the 
'equals' methods in this class
+         * (indirectly, through 'kernel' comparison). We need to be outside 
the synchronized block for having
+         * the locks taken in same order (WeakHashSet lock before the 
ContextualParameters lock).
+         */
         return 
factory.createConcatenatedTransform(factory.createConcatenatedTransform(n, 
kernel), d);
     }