/**
*
* Copyright 2003-2004 The Apache Software Foundation
*
* 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.apache.geronimo.gbean.runtime;
import java.util.Set;
import java.util.Iterator;
import javax.management.ObjectName;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.geronimo.gbean.GReferenceInfo;
import org.apache.geronimo.gbean.InvalidConfigurationException;
import org.apache.geronimo.kernel.DependencyManager;
import org.apache.geronimo.kernel.Kernel;
import org.apache.geronimo.kernel.lifecycle.LifecycleAdapter;
import org.apache.geronimo.kernel.lifecycle.LifecycleListener;
import org.apache.geronimo.kernel.management.State;
/**
* @version $Rev: 71492 $ $Date: 2004-11-14 21:31:50 -0800 (Sun, 14 Nov 2004) $
*/
public class GBeanSingleReference extends AbstractGBeanReference {
private static final Log log = LogFactory.getLog(GBeanSingleReference.class);
/**
* Is the GBeanMBean waitng for me to start?
*/
private boolean waitingForMe = false;
/**
* The object to which the proxy is bound
*/
private ObjectName proxyTarget;
public GBeanSingleReference(GBeanInstance gbeanInstance, GReferenceInfo referenceInfo, Kernel kernel, DependencyManager dependencyManager) throws InvalidConfigurationException {
super(gbeanInstance, referenceInfo, kernel, dependencyManager);
}
public synchronized boolean start() {
// We only need to start if there are patterns and we don't already have a proxy
if (!getPatterns().isEmpty() && getProxy() == null) {
//
// We must have exactally one running target
//
ObjectName objectName = getGBeanInstance().getObjectNameObject();
Set targets = getTargets();
if (targets.size() == 0) {
waitingForMe = true;
log.debug("Waiting to start " + objectName + " because no targets are running for reference " + getName() +" matching the patternspatterns " + getPatternsText());
return false;
} else if (targets.size() > 1) {
waitingForMe = true;
log.debug("Waiting to start " + objectName + " because more then one targets are running for the single valued reference " + getName() +" matching the patternspatterns " + getPatternsText());
return false;
}
waitingForMe = false;
// stop all gbeans that would match our patterns from starting
DependencyManager dependencyManager = getDependencyManager();
dependencyManager.addStartHolds(objectName, getPatterns());
// add a dependency on our target and create the proxy
ObjectName target = (ObjectName) targets.iterator().next();
setProxy(getKernel().getProxyManager().createProxy(target, getReferenceType()));
proxyTarget = target;
dependencyManager.addDependency(objectName, target);
}
return true;
}
private String getPatternsText() {
StringBuffer buf = new StringBuffer();
Set patterns = getPatterns();
for (Iterator iterator = patterns.iterator(); iterator.hasNext();) {
ObjectName objectName = (ObjectName) iterator.next();
buf.append(objectName.getCanonicalName()).append(" ");
}
return buf.toString();
}
public synchronized void stop() {
waitingForMe = false;
ObjectName objectName = getGBeanInstance().getObjectNameObject();
Set patterns = getPatterns();
DependencyManager dependencyManager = getDependencyManager();
if (!patterns.isEmpty()) {
dependencyManager.removeStartHolds(objectName, patterns);
}
Object proxy = getProxy();
if (proxy != null) {
dependencyManager.removeDependency(objectName, proxyTarget);
getKernel().getProxyManager().destroyProxy(proxy);
setProxy(null);
proxyTarget = null;
}
}
protected synchronized void targetAdded(ObjectName target) {
// if we are running, and we now have two valid targets, which is an illegal state so we need to fail
GBeanInstance gbeanInstance = getGBeanInstance();
if (gbeanInstance.getStateInstance() == State.RUNNING) {
log.error("Illegal state: two or more targets are not running for a signle valued reference: " + getDescription() +
", currentTarget=" + proxyTarget +
", newTarget=" + target);
gbeanInstance.referenceFailed();
} else if (waitingForMe) {
Set targets = getTargets();
if (targets.size() == 1) {
// the gbean was waiting for me and not there is now just one target
attemptFullStart();
}
}
}
protected synchronized void targetRemoved(ObjectName target) {
GBeanInstance gbeanInstance = getGBeanInstance();
if (gbeanInstance.getStateInstance() == State.RUNNING) {
// we no longer have a valid target, which is an illegal state so we need to fail
log.error("Illegal state: current target for a signle valued reference stopped: " + getDescription() +
", currentTarget=" + target);
gbeanInstance.referenceFailed();
} else if (waitingForMe) {
Set targets = getTargets();
if (targets.size() == 1) {
// the gbean was waiting for me and not there is now just one target
attemptFullStart();
}
}
}
private synchronized void attemptFullStart() {
try {
// there could be an issue with really badly written components holding up a stop when the
// component never reached the starting phase... then a target registers and we automatically
// attempt to restart
waitingForMe = false;
getGBeanInstance().start();
} catch (Exception e) {
log.warn("Exception occured while attempting to fully start: objectName=" + getGBeanInstance().getObjectName(), e);
}
}
protected LifecycleListener createLifecycleListener() {
return new LifecycleAdapter() {
public void running(ObjectName objectName) {
addTarget(objectName);
}
public void stopped(ObjectName objectName) {
removeTarget(objectName);
}
public void failed(ObjectName objectName) {
removeTarget(objectName);
}
public void unloaded(ObjectName objectName) {
removeTarget(objectName);
}
};
}
}