Author: reto
Date: Fri Apr 29 18:13:58 2011
New Revision: 1097903
URL: http://svn.apache.org/viewvc?rev=1097903&view=rev
Log:
CLEREZZA-503: Keeping weak references to MGraphListeners
Modified:
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/TripleCollection.java
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/AbstractTripleCollection.java
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/DelayedNotificator.java
Modified:
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/TripleCollection.java
URL:
http://svn.apache.org/viewvc/incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/TripleCollection.java?rev=1097903&r1=1097902&r2=1097903&view=diff
==============================================================================
---
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/TripleCollection.java
(original)
+++
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/TripleCollection.java
Fri Apr 29 18:13:58 2011
@@ -67,12 +67,16 @@ public interface TripleCollection extend
* only partially propagate their changes to the listener. They should
* describe the behavior in the documentation of the class.
*
+ * Implementations should keep weak references the listeners, so that
the
+ * listener can be garbage collected if its no longer referenced by
another
+ * object.
+ *
* If delay is 0 notification will happen synchroneously.
*
* @param listener The listener that will be notified
* @param filter The triple filter with which triples are tested,
* that were part of the modification.
- * @param delay The time period afer which the listener will be
notified.
+ * @param delay The time period afer which the listener will be
notified in milliseconds.
*/
public void addGraphListener(GraphListener listener, FilterTriple
filter,
long delay);
Modified:
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/AbstractTripleCollection.java
URL:
http://svn.apache.org/viewvc/incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/AbstractTripleCollection.java?rev=1097903&r1=1097902&r2=1097903&view=diff
==============================================================================
---
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/AbstractTripleCollection.java
(original)
+++
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/AbstractTripleCollection.java
Fri Apr 29 18:13:58 2011
@@ -18,6 +18,7 @@
*/
package org.apache.clerezza.rdf.core.impl;
+import java.lang.ref.WeakReference;
import java.util.AbstractCollection;
import java.util.Collection;
import java.util.Collections;
@@ -178,9 +179,16 @@ public abstract class AbstractTripleColl
*/
protected void dispatchEvent(GraphEvent event) {
synchronized(listenerConfigs) {
- for (ListenerConfiguration config : listenerConfigs) {
+ Iterator<ListenerConfiguration> iter =
listenerConfigs.iterator();
+ while (iter.hasNext()) {
+ ListenerConfiguration config = iter.next();
+ GraphListener registeredListener =
config.getListener();
+ if (registeredListener == null) {
+ iter.remove();
+ continue;
+ }
if
(config.getFilter().match(event.getTriple())) {
-
delayedNotificator.sendEventToListener(config.getListener(), event);
+
delayedNotificator.sendEventToListener(registeredListener, event);
}
}
}
@@ -206,7 +214,8 @@ public abstract class AbstractTripleColl
Iterator<ListenerConfiguration> iter =
listenerConfigs.iterator();
while (iter.hasNext()) {
ListenerConfiguration listenerConfig =
iter.next();
- if
(listenerConfig.getListener().equals(listener)) {
+ GraphListener registeredListener =
listenerConfig.getListener();
+ if ((registeredListener == null) ||
(registeredListener.equals(listener))) {
iter.remove();
}
}
@@ -216,11 +225,11 @@ public abstract class AbstractTripleColl
private static class ListenerConfiguration {
- private GraphListener listener;
+ private WeakReference<GraphListener> listenerRef;
private FilterTriple filter;
private ListenerConfiguration(GraphListener listener,
FilterTriple filter) {
- this.listener = listener;
+ this.listenerRef = new
WeakReference<GraphListener>(listener);
this.filter = filter;
}
@@ -228,6 +237,7 @@ public abstract class AbstractTripleColl
* @return the listener
*/
GraphListener getListener() {
+ GraphListener listener = listenerRef.get();
return listener;
}
Modified:
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/DelayedNotificator.java
URL:
http://svn.apache.org/viewvc/incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/DelayedNotificator.java?rev=1097903&r1=1097902&r2=1097903&view=diff
==============================================================================
---
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/DelayedNotificator.java
(original)
+++
incubator/clerezza/trunk/parent/rdf.core/src/main/java/org/apache/clerezza/rdf/core/impl/DelayedNotificator.java
Fri Apr 29 18:13:58 2011
@@ -18,15 +18,13 @@
*/
package org.apache.clerezza.rdf.core.impl;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Timer;
-import java.util.TimerTask;
+import java.lang.ref.WeakReference;
+import java.util.*;
+
import org.apache.clerezza.rdf.core.event.GraphEvent;
import org.apache.clerezza.rdf.core.event.GraphListener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
/**
*
@@ -34,23 +32,20 @@ import org.apache.clerezza.rdf.core.even
*/
class DelayedNotificator {
+ private static final Logger log =
LoggerFactory.getLogger(DelayedNotificator.class);
private static Timer timer = new Timer("Event delivery timer",true);
static class ListenerHolder {
long delay;
List<GraphEvent> events = null;
- GraphListener listener;
+ WeakReference<GraphListener> listenerRef;
public ListenerHolder(GraphListener listener, long delay) {
- this.listener = listener;
+ this.listenerRef = new
WeakReference<GraphListener>(listener);
this.delay = delay;
}
- private ListenerHolder(long delay) {
- throw new UnsupportedOperationException("Not yet
implemented");
- }
-
private void registerEvent(GraphEvent event) {
synchronized (this) {
if (events == null) {
@@ -65,7 +60,16 @@ class DelayedNotificator {
eventsLocal =
events;
events = null;
}
-
listener.graphChanged(eventsLocal);
+ GraphListener listener
= listenerRef.get();
+ if (listener == null) {
+
log.debug("Ignoring garbage collected listener");
+ } else {
+ try {
+
listener.graphChanged(eventsLocal);
+ } catch
(Exception e) {
+
log.warn("Exception delivering graph event", e);
+ }
+ }
}
}, delay);
} else {
@@ -74,25 +78,26 @@ class DelayedNotificator {
}
}
}
- private Map<GraphListener, ListenerHolder> map =
Collections.synchronizedMap(
- new HashMap<GraphListener, ListenerHolder>());
+
+ private final Map<GraphListener, ListenerHolder> map =
Collections.synchronizedMap(
+ new WeakHashMap<GraphListener, ListenerHolder>());
void addDelayedListener(GraphListener listener, long delay) {
map.put(listener, new ListenerHolder(listener, delay));
}
/**
- * removes a Listener, this doesn't prevent the listener from receiving
+ * removes a Listener, this doesn't prevent the listenerRef from
receiving
* events alreay scheduled.
*
- * @param listener
+ * @param listenerRef
*/
void removeDelayedListener(GraphListener listener) {
map.remove(listener);
}
/**
- * if the listener has not been registered as delayed listener te
events is
+ * if the listenerRef has not been registered as delayed listenerRef te
events is
* forwarded synchroneously
* @param event
*/
