/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jackrabbit.jcr2spi.hierarchy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.jackrabbit.jcr2spi.observation.InternalEventListener;
import org.apache.jackrabbit.jcr2spi.WorkspaceManager;
import org.apache.jackrabbit.jcr2spi.config.CacheBehaviour;
import org.apache.jackrabbit.spi.EventFilter;
import org.apache.jackrabbit.spi.Event;
import org.apache.jackrabbit.spi.EventBundle;
import org.apache.jackrabbit.spi.NodeId;
import org.apache.jackrabbit.spi.Path;
import javax.jcr.RepositoryException;
import java.util.Collection;
import java.util.Collections;
import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
/**
* <code>HierarchyEventListener</code>...
*/
public class HierarchyEventListener implements InternalEventListener {
private static Logger log = LoggerFactory.getLogger(HierarchyEventListener.class);
private final HierarchyManager hierarchyMgr;
private final Collection eventFilter;
public HierarchyEventListener(WorkspaceManager wspManager,
HierarchyManager hierarchyMgr,
CacheBehaviour cacheBehaviour) {
this.hierarchyMgr = hierarchyMgr;
if (cacheBehaviour == CacheBehaviour.OBSERVATION) {
EventFilter filter = null;
try {
// listen to all events except 'local' ones
Path root = wspManager.getPathFactory().getRootPath();
filter = wspManager.createEventFilter(Event.ALL_TYPES, root, true, null, null, true);
} catch (RepositoryException e) {
// spi does not support observation, or another error occurred.
}
this.eventFilter = (filter == null) ? Collections.EMPTY_LIST : Collections.singletonList(filter);
try {
wspManager.addEventListener(this);
} catch (RepositoryException e) {
// spi does not support observation, or another error occurred.
}
} else {
this.eventFilter = Collections.EMPTY_LIST;
}
}
//----------------------------------------------< InternalEventListener >---
/**
* @see InternalEventListener#getEventFilters()
*/
public Collection getEventFilters() {
return eventFilter;
}
/**
* Processes <code>events</code> and invalidates cached <code>ItemState</code>s
* accordingly. Note that this performed for both local and non-local changes,
* since workspace operations are reported as local changes as well and
* might have invoked changes (autocreated items etc.).
*
* @param eventBundle
* @see InternalEventListener#onEvent(EventBundle)
*/
public void onEvent(EventBundle eventBundle) {
if (eventBundle.isLocal()) {
log.debug("Local event bundle -> not processed by HierarchyEventListener.");
return;
}
pushEvents(getEventCollection(eventBundle));
}
/**
* Retrieve the workspace state(s) affected by the given event and refresh
* them accordingly.
*
* @param events
*/
private void pushEvents(Collection events) {
if (events.isEmpty()) {
log.debug("Empty event bundle");
return;
}
// collect set of removed node ids
Set removedEvents = new HashSet();
// separately collect the add events
Set addEvents = new HashSet();
for (Iterator it = events.iterator(); it.hasNext();) {
Event event = (Event) it.next();
int type = event.getType();
if (type == Event.NODE_REMOVED) {
// remember removed nodes separately for proper handling later on.
removedEvents.add(event.getItemId());
} else if (type == Event.NODE_ADDED || type == Event.PROPERTY_ADDED) {
addEvents.add(event);
it.remove();
}
}
/* Process ADD-events.
In case of persisting transients modifications, the event-set may
still contain events that are not covered by the changeLog such as
new version-history or other autocreated properties and nodes.
Add events need to be processed hierarchically, since its not possible
to add a new child reference to a state that is not yet present in
the state manager.
The 'progress' flag is used to make sure, that during each loop at
least one event has been processed and removed from the iterator.
If this is not the case, there are not parent states present in the
state manager that need to be updated and the remaining events may
be ignored.
*/
boolean progress = true;
while (!addEvents.isEmpty() && progress) {
progress = false;
for (Iterator it = addEvents.iterator(); it.hasNext();) {
Event ev = (Event) it.next();
NodeEntry parent = (ev.getParentId() != null) ? (NodeEntry) hierarchyMgr.lookup(ev.getParentId()) : null;
if (parent != null) {
parent.refresh(ev);
it.remove();
progress = true;
}
}
}
/* process all other events (removal, property changed) */
for (Iterator it = events.iterator(); it.hasNext(); ) {
Event event = (Event) it.next();
int type = event.getType();
NodeId parentId = event.getParentId();
NodeEntry parent = (parentId != null) ? (NodeEntry) hierarchyMgr.lookup(parentId) : null;
if (type == Event.NODE_REMOVED || type == Event.PROPERTY_REMOVED) {
// notify parent about removal if its child-entry.
// - if parent is 'null' (i.e. not yet loaded) the child-entry does
// not exist either -> no need to inform child-entry
// - if parent got removed with the same event-bundle
// only remove the parent an skip this event.
if (parent != null && !removedEvents.contains(parentId)) {
parent.refresh(event);
}
} else if (type == Event.PROPERTY_CHANGED) {
// notify parent in case jcr:mixintypes or jcr:uuid was changed.
// if parent is 'null' (i.e. not yet loaded) the prop-entry does
// not exist either -> no need to inform propEntry
if (parent != null) {
parent.refresh(event);
}
} else {
// should never occur
throw new IllegalArgumentException("Invalid event type: " + event.getType());
}
}
}
private static Collection getEventCollection(EventBundle eventBundle) {
List evs = new ArrayList();
for (Iterator it = eventBundle.getEvents(); it.hasNext();) {
evs.add(it.next());
}
return evs;
}
}