svn commit: r709127 - /incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/GadgetFeatureRegistry.java

[et...@apache.org]

Author: etnu
Date: Thu Oct 30 02:56:26 2008
New Revision: 709127

URL: http://svn.apache.org/viewvc?rev=709127&view=rev
Log:
Fixed a synchronization problem in feature dependency chain caching logic.


Modified:
    incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/GadgetFeatureRegistry.java

Modified: incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/GadgetFeatureRegistry.java
URL: http://svn.apache.org/viewvc/incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/GadgetFeatureRegistry.java?rev=709127&r1=709126&r2=709127&view=diff
==============================================================================
--- incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/GadgetFeatureRegistry.java (original)
+++ incubator/shindig/trunk/java/gadgets/src/main/java/org/apache/shindig/gadgets/GadgetFeatureRegistry.java Thu Oct 30 02:56:26 2008
@@ -30,6 +30,8 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.logging.Logger;
 
 /**
@@ -48,6 +50,7 @@
   // Caches the transitive dependencies to enable faster lookups.
   private final Map<Collection<String>, Collection<GadgetFeature>> cache
       = Maps.newHashMap();
+  private final ReadWriteLock cacheLock = new ReentrantReadWriteLock();
 
   private boolean graphComplete = false;
 
@@ -130,7 +133,9 @@
     }
     // We use the cache only for situations where all needed are available.
     // if any are missing, the result won't be cached.
+    cacheLock.readLock().lock();
     Collection<GadgetFeature> libCache = cache.get(needed);
+    cacheLock.readLock().unlock();
     if (libCache != null) {
       return libCache;
     }
@@ -145,7 +150,9 @@
       }
     }
     if (unsupported == null || unsupported.isEmpty()) {
+      cacheLock.writeLock().lock();
       cache.put(needed, Collections.unmodifiableList(ret));
+      cacheLock.writeLock().unlock();
     }
     return ret;
   }