Author: gscokart
Date: Wed Aug 20 06:28:52 2008
New Revision: 687325
URL: http://svn.apache.org/viewvc?rev=687325&view=rev
Log:
Thread safety fix (list of delegates were modified and copied concurrently
without common lock). The hashtable is thread safe and not published outside
the class, so no need to copy it (synchronize non atomic modification is
enought). However, the list contained in the delegates hashtable are published
and should thus be copied. I put the copy in the add method so that the
getDelegates doesn't need to be synchronized.
Modified:
ant/core/trunk/src/main/org/apache/tools/ant/PropertyHelper.java
Modified: ant/core/trunk/src/main/org/apache/tools/ant/PropertyHelper.java
URL:
http://svn.apache.org/viewvc/ant/core/trunk/src/main/org/apache/tools/ant/PropertyHelper.java?rev=687325&r1=687324&r2=687325&view=diff
==============================================================================
--- ant/core/trunk/src/main/org/apache/tools/ant/PropertyHelper.java (original)
+++ ant/core/trunk/src/main/org/apache/tools/ant/PropertyHelper.java Wed Aug 20
06:28:52 2008
@@ -177,7 +177,7 @@
private Project project;
private PropertyHelper next;
- private volatile Hashtable delegates = new Hashtable();
+ private Hashtable delegates = new Hashtable();
/** Project properties map (usually String to String). */
private Hashtable properties = new Hashtable();
@@ -924,35 +924,33 @@
* @since Ant 1.8
*/
public void add(Delegate delegate) {
- synchronized (Delegate.class) {
- Hashtable newDelegates = (Hashtable) delegates.clone();
+ synchronized (delegates) {
for (Iterator iter = getDelegateInterfaces(delegate).iterator();
iter.hasNext();) {
Object key = iter.next();
- List list = (List) newDelegates.get(key);
+ List list = (List) delegates.get(key);
if (list == null) {
list = new ArrayList();
- newDelegates.put(key, list);
- }
- if (list.contains(delegate)) {
+ } else {
+ list = new ArrayList(list);
list.remove(delegate);
}
list.add(0, delegate);
+ delegates.put(key, Collections.unmodifiableList(list));
}
- delegates = newDelegates;
}
}
/**
* Get the Collection of delegates of the specified type.
- * @param type delegate type.
+ *
+ * @param type
+ * delegate type.
* @return Collection.
* @since Ant 1.8
*/
protected List getDelegates(Class type) {
- Hashtable curDelegates = delegates;
- return curDelegates.containsKey(type)
- ? (List) new ArrayList((List) curDelegates.get(type))
- : Collections.EMPTY_LIST;
+ List r = (List) delegates.get(type);
+ return r == null ? Collections.EMPTY_LIST : r;
}
/**
