svn commit: r1215539 - /uima/uimaj/trunk/uimaj-core/src/main/java/org/apache/uima/resource/impl/ResourceManager_impl.java

[sc...@apache.org]

Author: schor
Date: Sat Dec 17 17:59:54 2011
New Revision: 1215539

URL: http://svn.apache.org/viewvc?rev=1215539&view=rev
Log:
no Jira - added comment 

Modified:
    uima/uimaj/trunk/uimaj-core/src/main/java/org/apache/uima/resource/impl/ResourceManager_impl.java

Modified: uima/uimaj/trunk/uimaj-core/src/main/java/org/apache/uima/resource/impl/ResourceManager_impl.java
URL: http://svn.apache.org/viewvc/uima/uimaj/trunk/uimaj-core/src/main/java/org/apache/uima/resource/impl/ResourceManager_impl.java?rev=1215539&r1=1215538&r2=1215539&view=diff
==============================================================================
--- uima/uimaj/trunk/uimaj-core/src/main/java/org/apache/uima/resource/impl/ResourceManager_impl.java (original)
+++ uima/uimaj/trunk/uimaj-core/src/main/java/org/apache/uima/resource/impl/ResourceManager_impl.java Sat Dec 17 17:59:54 2011
@@ -109,6 +109,13 @@ public class ResourceManager_impl implem
   /**
    * Cache of imported descriptors, so that parsed objects can be reused if the
    * same URL is imported more than once.
+   * 
+   * Use Case where synchronization is needed:
+   *   running multiple instances on multiple threads, sharing a common resource manager,
+   *   the initialization that merges typePriorities happens lazily, when using Cas Multipliers,
+   *   and occurs when the first getCas call happens on a thread.  Although these calls
+   *   are synchronized among themselves, any other use of this map that might occur
+   *   simultaneously is not.
    */
   private Map<String,XMLizable> importCache = Collections.synchronizedMap(new HashMap<String,XMLizable>());