/*
* Copyright 2011 NCHOVY
*
* Licensed 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.krakenapps.event.api.impl;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.felix.ipojo.annotations.Component;
import org.apache.felix.ipojo.annotations.Invalidate;
import org.apache.felix.ipojo.annotations.Provides;
import org.apache.felix.ipojo.annotations.Requires;
import org.apache.felix.ipojo.annotations.Validate;
import org.krakenapps.event.api.Event;
import org.krakenapps.event.api.EventDispatcher;
import org.krakenapps.event.api.EventKey;
import org.krakenapps.event.api.EventPipe;
import org.osgi.service.prefs.BackingStoreException;
import org.osgi.service.prefs.Preferences;
import org.osgi.service.prefs.PreferencesService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@Component(name = "event-dispatcher")
@Provides
public class EventDispatcherImpl implements EventDispatcher {
private final Logger logger = LoggerFactory.getLogger(EventDispatcherImpl.class.getName());
private CopyOnWriteArraySet<EventPipe> pipes;
@Requires
private PreferencesService prefsvc;
private AtomicInteger next;
private volatile int reserved;
@Validate
public void start() {
pipes = new CopyOnWriteArraySet<EventPipe>();
next = new AtomicInteger(prefsvc.getSystemPreferences().getInt("next", 1));
try {
reserve(10);
} catch (IllegalStateException e) {
logger.error("kraken event api: cannot save event id", e);
}
}
@Invalidate
public void stop() {
try {
reserve(10);
} catch (IllegalStateException e) {
logger.error("kraken event api: cannot save event id", e);
}
}
private void reserve(int count) throws IllegalStateException {
try {
reserved = next.get() + count;
if (prefsvc != null) {
Preferences p = prefsvc.getSystemPreferences();
p.putInt("next", reserved);
p.flush();
p.sync();
}
} catch (BackingStoreException e) {
throw new IllegalStateException(e);
}
}
@Override
public void dispatch(Event event) {
if (logger.isTraceEnabled())
logger.trace("kraken event api: dispatching event [{}]", event);
if (event.getKey() == null) {
int id = next.getAndIncrement();
event.setKey(new EventKey(0, id));
// save reserved id range periodically
if (id > reserved)
reserve(100);
}
for (EventPipe pipe : pipes) {
try {
pipe.onEvent(event);
} catch (Exception e) {
logger.warn("kraken event api: event pipe should not throw any exception", e);
}
}
}
@Override
public void ack(Event event) {
if (logger.isTraceEnabled())
logger.trace("kraken event api: dispatching event ack [{}]", event);
for (EventPipe pipe : pipes) {
try {
pipe.onEventAcked(event);
} catch (Exception e) {
logger.warn("kraken event api: event pipe should not throw any exception", e);
}
}
}
@Override
public void addEventPipe(EventPipe pipe) {
logger.trace("kraken event api: adding event pipe [{}]", pipe);
pipes.add(pipe);
}
@Override
public void removeEventPipe(EventPipe pipe) {
logger.trace("kraken event api: removing event pipe [{}]", pipe);
pipes.remove(pipe);
}
}