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/*******************************************************************************
* Copyright (c) 2010 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* ARTAL Technologies <simon.chemouil@artal.fr> - Allow wildcards in topic names
*******************************************************************************/
package org.eclipse.e4.core.di.internal.extensions;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Dictionary;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import javax.annotation.PreDestroy;
import org.eclipse.e4.core.di.IInjector;
import org.eclipse.e4.core.di.InjectionException;
import org.eclipse.e4.core.di.extensions.EventTopic;
import org.eclipse.e4.core.di.extensions.EventUtils;
import org.eclipse.e4.core.di.suppliers.ExtendedObjectSupplier;
import org.eclipse.e4.core.di.suppliers.IObjectDescriptor;
import org.eclipse.e4.core.di.suppliers.IRequestor;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleException;
import org.osgi.framework.ServiceRegistration;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventAdmin;
import org.osgi.service.event.EventConstants;
import org.osgi.service.event.EventHandler;
public class EventObjectSupplier extends ExtendedObjectSupplier {
// This is a temporary code to ensure that bundle containing
// EventAdmin implementation is started. This code it to be removed once
// the proper method to start EventAdmin is added.
static {
if (getEventAdmin() == null) {
Bundle[] bundles = DIEActivator.getDefault().getBundleContext().getBundles();
for (Bundle bundle : bundles) {
if (!"org.eclipse.equinox.event".equals(bundle.getSymbolicName())) //$NON-NLS-1$
continue;
try {
bundle.start(Bundle.START_TRANSIENT);
} catch (BundleException e) {
e.printStackTrace();
}
break;
}
}
}
protected Map<String, Event> currentEvents = new HashMap<String, Event>();
class DIEventHandler implements EventHandler {
final private IRequestor requestor;
final private String topic;
public DIEventHandler(String topic, IRequestor requestor) {
this.topic = topic;
this.requestor = requestor;
}
public void handleEvent(Event event) {
if (!requestor.isValid()) {
unsubscribe(requestor);
return;
}
addCurrentEvent(topic, event);
requestor.resolveArguments(false);
removeCurrentEvent(topic);
requestor.execute();
}
}
// A combo of { IRequestor + topic } used in Map lookups
static private class Subscriber {
private IRequestor requestor;
private String topic;
public Subscriber(IRequestor requestor, String topic) {
super();
this.requestor = requestor;
this.topic = topic;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((requestor == null) ? 0 : requestor.hashCode());
result = prime * result + ((topic == null) ? 0 : topic.hashCode());
return result;
}
public IRequestor getRequestor() {
return requestor;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Subscriber other = (Subscriber) obj;
if (requestor == null) {
if (other.requestor != null)
return false;
} else if (!requestor.equals(other.requestor))
return false;
if (topic == null) {
if (other.topic != null)
return false;
} else if (!topic.equals(other.topic))
return false;
return true;
}
}
private Map<Subscriber, ServiceRegistration> registrations = new HashMap<Subscriber, ServiceRegistration>();
protected void addCurrentEvent(String topic, Event event) {
synchronized (currentEvents) {
currentEvents.put(topic, event);
}
}
protected void removeCurrentEvent(String topic) {
synchronized (currentEvents) {
currentEvents.remove(topic);
}
}
@Override
public Object get(IObjectDescriptor descriptor, IRequestor requestor, boolean track, boolean group) {
if (descriptor == null)
return null;
String topic = getTopic(descriptor);
EventAdmin eventAdmin = getEventAdmin();
if (topic == null || eventAdmin == null || topic.length() == 0)
return IInjector.NOT_A_VALUE;
if (track)
subscribe(topic, eventAdmin, requestor);
if (!currentEvents.containsKey(topic))
return IInjector.NOT_A_VALUE;
// convert to fit destination
Class<?> descriptorsClass = getDesiredClass(descriptor.getDesiredType());
if (descriptorsClass.equals(Event.class))
return currentEvents.get(topic);
return currentEvents.get(topic).getProperty(EventUtils.DATA);
}
private void subscribe(String topic, EventAdmin eventAdmin, IRequestor requestor) {
Subscriber subscriber = new Subscriber(requestor, topic);
synchronized (registrations) {
if (registrations.containsKey(subscriber))
return;
}
BundleContext bundleContext = DIEActivator.getDefault().getBundleContext();
if (bundleContext == null)
throw new InjectionException("Unable to subscribe to events: org.eclipse.e4.core.di.extensions bundle is not activated"); //$NON-NLS-1$
String[] topics = new String[] {topic};
Dictionary<String, Object> d = new Hashtable<String, Object>();
d.put(EventConstants.EVENT_TOPIC, topics);
EventHandler wrappedHandler = makeHandler(topic, requestor);
ServiceRegistration registration = bundleContext.registerService(EventHandler.class.getName(), wrappedHandler, d);
// due to the way requestors are constructed this limited synch should be OK
synchronized (registrations) {
registrations.put(subscriber, registration);
}
}
protected EventHandler makeHandler(String topic, IRequestor requestor) {
return new DIEventHandler(topic, requestor);
}
protected String getTopic(IObjectDescriptor descriptor) {
if (descriptor == null)
return null;
EventTopic qualifier = descriptor.getQualifier(EventTopic.class);
return qualifier.value();
}
static private EventAdmin getEventAdmin() {
return DIEActivator.getDefault().getEventAdmin();
}
protected void unsubscribe(IRequestor requestor) {
synchronized (registrations) {
Iterator<Entry<Subscriber, ServiceRegistration>> i = registrations.entrySet().iterator();
while (i.hasNext()) {
Entry<Subscriber, ServiceRegistration> entry = i.next();
Subscriber key = entry.getKey();
if (key.getRequestor() != requestor)
continue;
ServiceRegistration registration = entry.getValue();
registration.unregister();
i.remove();
}
}
}
@PreDestroy
public void dispose() {
ServiceRegistration[] array;
synchronized (registrations) {
Collection<ServiceRegistration> values = registrations.values();
array = values.toArray(new ServiceRegistration[values.size()]);
registrations.clear();
}
for (int i = 0; i < array.length; i++) {
array[i].unregister();
}
}
private Class<?> getDesiredClass(Type desiredType) {
if (desiredType instanceof Class<?>)
return (Class<?>) desiredType;
if (desiredType instanceof ParameterizedType) {
Type rawType = ((ParameterizedType) desiredType).getRawType();
if (rawType instanceof Class<?>)
return (Class<?>) rawType;
}
return null;
}
}
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