/*
* JBoss, Home of Professional Open Source.
* Copyright 2014, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.as.controller.registry;
import java.util.Collection;
import java.util.ListIterator;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import org.jboss.as.controller.PathElement;
import org.jboss.as.controller.notification.Notification;
import org.jboss.as.controller.notification.NotificationHandler;
/**
* A registry of {@code NotificationHandlerEntry} (in a tree) corresponding to a {@link PathElement#getValue()}.
*
* @author <a href="http://jmesnil.net/">Jeff Mesnil</a> (c) 2014 Red Hat inc.
*/
class NotificationHandlerNodeRegistry {
/**
* The value of the node's PathElement (can be {@code null} for the root node).
*/
private final String value;
/**
* The node's parent (or {@code null} for the root node).
*/
private final NotificationHandlerNodeSubregistry parent;
@SuppressWarnings("unused")
private volatile Map<String, NotificationHandlerNodeSubregistry> children;
/**
* The collection of ({@code NotificationHandler}, {@code NotificationFilter})
*/
private volatile Collection<ConcreteNotificationHandlerRegistration.NotificationHandlerEntry> entries;
private static final AtomicMapFieldUpdater<NotificationHandlerNodeRegistry, String, NotificationHandlerNodeSubregistry> childrenUpdater = AtomicMapFieldUpdater.newMapUpdater(AtomicReferenceFieldUpdater.newUpdater(NotificationHandlerNodeRegistry.class, Map.class, "children"));
NotificationHandlerNodeRegistry(String value, NotificationHandlerNodeSubregistry parent) {
this.value = value;
this.parent = parent;
childrenUpdater.clear(this);
entries = new CopyOnWriteArraySet<ConcreteNotificationHandlerRegistration.NotificationHandlerEntry>();
}
/**
* Register the entry here (if the registry is the leaf node) or continue to traverse the tree
*/
void registerEntry(ListIterator<PathElement> iterator, ConcreteNotificationHandlerRegistration.NotificationHandlerEntry entry) {
if (!iterator.hasNext()) {
// leaf node, register the entry here
entries.add(entry);
return;
}
PathElement element = iterator.next();
NotificationHandlerNodeSubregistry subregistry = getOrCreateSubregistry(element.getKey());
subregistry.registerEntry(iterator, element.getValue(), entry);
}
/**
* Unregister the entry from here (if the registry is the leaf node) or continue to traverse the tree
*/
void unregisterEntry(ListIterator<PathElement> iterator, ConcreteNotificationHandlerRegistration.NotificationHandlerEntry entry) {
if (!iterator.hasNext()) {
// leaf node, unregister the entry here
entries.remove(entry);
return;
}
PathElement element = iterator.next();
final NotificationHandlerNodeSubregistry subregistry = children.get(element.getKey());
if (subregistry == null) {
return;
}
subregistry.unregisterEntry(iterator, element.getValue(), entry);
}
/**
* Collect all the entries in the {@code handler} notifications (if the registry is the leaf node) or continue to traverse the tree
* Only entries that are not filtered out after calling {@link org.jboss.as.controller.notification.NotificationFilter#isNotificationEnabled(org.jboss.as.controller.notification.Notification)} for the given {@code notification} are collected
*/
void findEntries(ListIterator<PathElement> iterator, Collection<NotificationHandler> handlers, Notification notification) {
if (!iterator.hasNext()) {
for (ConcreteNotificationHandlerRegistration.NotificationHandlerEntry entry : entries) {
if (entry.getFilter().isNotificationEnabled(notification)) {
handlers.add(entry.getHandler());
}
}
return;
}
PathElement next = iterator.next();
try {
final NotificationHandlerNodeSubregistry subregistry = children.get(next.getKey());
if (subregistry == null) {
return;
}
subregistry.findHandlers(iterator, next.getValue(), notification, handlers);
} finally {
iterator.previous();
}
}
String getLocationString() {
if (parent == null) {
return "";
} else {
return parent.getLocationString() + value + ")";
}
}
/**
* Create a {@code NotificationHandlerNodeSubregistry} for the give {@code key} or use the existing one if it already exists.
*
* Copied from {@link org.jboss.as.controller.registry.ConcreteResourceRegistration#getOrCreateSubregistry(String)}
*/
NotificationHandlerNodeSubregistry getOrCreateSubregistry(final String key) {
for (;;) {
final Map<String, NotificationHandlerNodeSubregistry> snapshot = childrenUpdater.get(this);
final NotificationHandlerNodeSubregistry subregistry = snapshot.get(key);
if (subregistry != null) {
return subregistry;
} else {
final NotificationHandlerNodeSubregistry newRegistry = new NotificationHandlerNodeSubregistry(key, this);
if (childrenUpdater.putAtomic(this, key, newRegistry, snapshot)) {
return newRegistry;
}
// otherwise, retry the loop because the map changed
}
}
}
}