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The basic runtime tools and interfaces for intarsys components.
/*
* Copyright (c) 2007, intarsys consulting GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* - Neither the name of intarsys nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package de.intarsys.tools.event;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import de.intarsys.tools.component.IStartStop;
/**
* A tool for intercepting and handling lifecycle related events.
*
*/
abstract public class LifecycleWatchdog implements IStartStop {
final private INotificationSupport object;
final private List armedObjects = new ArrayList();
private boolean started = false;
private String label;
/**
* A listener for object lifecycle events
*/
final protected INotificationListener listenObjectLifecycle = new INotificationListener() {
public void handleEvent(Event event) {
onObjectLifecycleEvent(event);
}
@Override
public String toString() {
return LifecycleWatchdog.this.toString();
}
};
/**
* A listener for factory lifecycle events
*/
final protected INotificationListener listenFactoryLifecycle = new INotificationListener() {
public void handleEvent(Event event) {
onFactoryLifecycleEvent(event);
}
@Override
public String toString() {
return LifecycleWatchdog.this.toString();
}
};
public LifecycleWatchdog(INotificationSupport factory) {
super();
if (factory == null) {
throw new NullPointerException("watchdog must have a factory");
}
this.object = factory;
}
protected void arm(INotificationSupport object) {
//
synchronized (armedObjects) {
armedObjects.add(object);
}
//
object.addNotificationListener(StartedEvent.ID, listenObjectLifecycle);
object
.addNotificationListener(ActivatedEvent.ID,
listenObjectLifecycle);
object.addNotificationListener(DeactivatedEvent.ID,
listenObjectLifecycle);
object.addNotificationListener(StopRequestedEvent.ID,
listenObjectLifecycle);
object.addNotificationListener(StoppedEvent.ID, listenObjectLifecycle);
}
protected void disarm(INotificationSupport object) {
//
synchronized (armedObjects) {
armedObjects.remove(object);
}
//
object.removeNotificationListener(StartedEvent.ID,
listenObjectLifecycle);
object.removeNotificationListener(ActivatedEvent.ID,
listenObjectLifecycle);
object.removeNotificationListener(DeactivatedEvent.ID,
listenObjectLifecycle);
object.removeNotificationListener(StopRequestedEvent.ID,
listenObjectLifecycle);
object.removeNotificationListener(StoppedEvent.ID,
listenObjectLifecycle);
}
public String getLabel() {
return label;
}
public INotificationSupport getObject() {
return object;
}
public boolean isStarted() {
return started;
}
final protected void myFactoryStarted(Event event) {
start();
}
final protected void myFactoryStopped(Event event) {
stop();
}
/**
* A previously armed IObject is activated.
*
* @param event
* The activation event instance
*/
final protected void myObjectActivated(Object object) {
objectActivated(object);
}
/**
* A new IObject is created and armed for further notification.
*
* @param event
* The activation event instance
*/
final protected void myObjectCreated(Object object) {
if (!supports(object)) {
return;
}
arm((INotificationSupport) object);
objectCreated(object);
}
/**
* A previously armed IObject is deactivated.
*
* @param event
* The activation event instance
*/
final protected void myObjectDeactivated(Object object) {
objectDeactivated(object);
}
/**
* A previously armed IObject is destroyed.
*
* @param event
* The activation event instance
*/
final protected void myObjectDestroyed(Object object) {
disarm((INotificationSupport) object);
objectDestroyed(object);
}
/**
* A previously armed IObject is started.
*
* @param event
* The activation event instance
*/
final protected void myObjectStarted(Object object) {
objectStarted(object);
}
/**
* A previously armed IObject is stopped. All notification listeners are
* removed.
*
* @param event
* The activation event instance
*/
final protected void myObjectStopped(Object object) {
disarm((INotificationSupport) object);
objectStopped(object);
}
/**
* A previously armed IObject is requested to stop.
*
* @param event
* The event instance
*/
final protected boolean myObjectStopRequested(Object object) {
return objectStopRequested(object);
}
/**
* Redefine to get informed when an IObject is activated.
*
* @param object
* The object that was activated.
*/
protected void objectActivated(Object object) {
// redefine
}
/**
* Redefine to get informed when an IObject is created.
*
* @param object
* The object that was created,
*/
protected void objectCreated(Object object) {
// redefine
}
/**
* Redefine to get informed when an IObject is deactivated.
*
* @param object
* the object that was deactivated.
*/
protected void objectDeactivated(Object object) {
// redefine
}
/**
* Redefine to get informed when an IObject is destroyed.
*
* @param object
* The object that was destroyed.
*/
protected void objectDestroyed(Object object) {
// redefine
}
/**
* Redefine to get informed when an IObject is started.
*
* @param object
* The object that was started.
*/
protected void objectStarted(Object object) {
// redefine
}
/**
* Redefine to get informed when an IObject is requested to stop.
*
* @param object
* The object that was stopped.
*/
protected void objectStopped(Object object) {
// redefine
}
/**
* Redefine to get informed when an IObject is stopped.
*
* @param object
* The object that should be stopped.
*/
protected boolean objectStopRequested(Object object) {
// redefine
return true;
}
/**
* A previously armed object is activated.
*
* @param event
* The activation event instance
*/
protected void onFactoryLifecycleEvent(Event event) {
if (event instanceof StartedEvent) {
myFactoryStarted(event);
} else if (event instanceof StoppedEvent) {
myFactoryStopped(event);
} else {
// ??
}
}
/**
* A previously armed object is activated.
*
* @param event
* The activation event instance
*/
protected void onObjectLifecycleEvent(Event event) {
if (event instanceof CreatedEvent) {
CreatedEvent cpe = (CreatedEvent) event;
myObjectCreated(cpe.getInstance());
} else if (event instanceof DestroyedEvent) {
myObjectDestroyed(event.getSource());
} else if (event instanceof StartedEvent) {
myObjectStarted(event.getSource());
} else if (event instanceof ActivatedEvent) {
myObjectActivated(event.getSource());
} else if (event instanceof DeactivatedEvent) {
myObjectDeactivated(event.getSource());
} else if (event instanceof StopRequestedEvent) {
event.setRc(myObjectStopRequested(event.getSource()));
} else if (event instanceof StoppedEvent) {
myObjectStopped(event.getSource());
} else {
// ??
}
}
public void setLabel(String label) {
this.label = label;
}
/**
* Arm the watchdog itself. From now it will listen to the creation of new
* instances.
*
* @see de.intarsys.tools.component.IStartStop#start()
*/
public void start() {
object.addNotificationListener(CreatedEvent.ID, listenObjectLifecycle);
started = true;
}
/**
* Arm the watchdog itself. From now it will listen to the creation of new
* instances.
*
* @see de.intarsys.tools.component.IStartStop#start()
*/
public void startAuto() {
object.addNotificationListener(StartedEvent.ID, listenFactoryLifecycle);
}
/**
* Disarm the watchdog itself. From now it will not longer listen to the
* creation of new instances.
*
* @see de.intarsys.tools.component.IStartStop#stop()
*/
public void stop() {
object.removeNotificationListener(CreatedEvent.ID,
listenObjectLifecycle);
// disarm all already armed IObject instances, use copy to
// avoid concurrent modification
List toBeDisarmed;
synchronized (armedObjects) {
toBeDisarmed = new ArrayList(armedObjects);
}
for (Iterator it = toBeDisarmed.iterator(); it.hasNext();) {
INotificationSupport object = (INotificationSupport) it.next();
disarm(object);
}
}
/*
* (non-Javadoc)
*
* @see de.intarsys.tools.component.IStartStop#stopRequested()
*/
public boolean stopRequested(Set visited) {
return true;
}
/**
* Answer true if we are interested in the object
* instance. If we are interested the watchdog will register itself for the
* lifecycle events.
*
* @param object
* The newly created object.
* @return Answer true if we are interested in the
* object instance.
*/
protected boolean supports(Object object) {
return true;
}
@Override
public String toString() {
return getLabel();
}
}
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