/*******************************************************************************
* Copyright (c) 2003, 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
*******************************************************************************/
package org.eclipse.osgi.internal.serviceregistry;
import org.eclipse.osgi.framework.debug.Debug;
import org.eclipse.osgi.framework.internal.core.BundleContextImpl;
import org.eclipse.osgi.framework.internal.core.FilterImpl;
import org.osgi.framework.*;
import org.osgi.framework.hooks.service.ListenerHook;
/**
* Service Listener delegate.
*/
class FilteredServiceListener implements ServiceListener, ListenerHook.ListenerInfo {
/** Filter for listener. */
private final FilterImpl filter;
/** Real listener. */
private final ServiceListener listener;
/** The bundle context */
private final BundleContextImpl context;
/** is this an AllServiceListener */
private final boolean allservices;
/** an objectClass required by the filter */
private final String objectClass;
/** indicates whether the listener has been removed */
private volatile boolean removed;
/**
* Constructor.
*
* @param context The bundle context of the bundle which added the specified service listener.
* @param filterstring The filter string specified when this service listener was added.
* @param listener The service listener object.
* @exception InvalidSyntaxException if the filter is invalid.
*/
FilteredServiceListener(final BundleContextImpl context, final ServiceListener listener, final String filterstring) throws InvalidSyntaxException {
if (filterstring == null) {
this.filter = null;
this.objectClass = null;
} else {
FilterImpl filterImpl = FilterImpl.newInstance(filterstring);
String clazz = filterImpl.getRequiredObjectClass();
if (clazz == null) {
this.objectClass = null;
this.filter = filterImpl;
} else {
this.objectClass = clazz.intern(); /*intern the name for future identity comparison */
this.filter = filterstring.equals(getObjectClassFilterString(this.objectClass)) ? null : filterImpl;
}
}
this.removed = false;
this.listener = listener;
this.context = context;
this.allservices = (listener instanceof AllServiceListener);
}
/**
* Receives notification that a service has had a lifecycle change.
*
* @param event The <code>ServiceEvent</code> object.
*/
public void serviceChanged(ServiceEvent event) {
ServiceReferenceImpl<?> reference = (ServiceReferenceImpl<?>) event.getServiceReference();
// first check if we can short circuit the filter match if the required objectClass does not match the event
objectClassCheck: if (objectClass != null) {
String[] classes = reference.getClasses();
int size = classes.length;
for (int i = 0; i < size; i++) {
if (classes[i] == objectClass) // objectClass strings have previously been interned for identity comparison
break objectClassCheck;
}
return; // no class in this event matches a required part of the filter; we do not need to deliver this event
}
// TODO could short circuit service.id filters as well since the id is constant for a registration.
if (!ServiceRegistry.hasListenServicePermission(event, context))
return;
if (Debug.DEBUG_EVENTS) {
String listenerName = this.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(this)); //$NON-NLS-1$
Debug.println("filterServiceEvent(" + listenerName + ", \"" + getFilter() + "\", " + reference.getRegistration().getProperties() + ")"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
}
event = filterMatch(event);
if (event == null) {
return;
}
if (allservices || ServiceRegistry.isAssignableTo(context, reference)) {
if (Debug.DEBUG_EVENTS) {
String listenerName = listener.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(listener)); //$NON-NLS-1$
Debug.println("dispatchFilteredServiceEvent(" + listenerName + ")"); //$NON-NLS-1$ //$NON-NLS-2$
}
listener.serviceChanged(event);
}
}
/**
* Returns a service event that should be delivered to the listener based on the filter evaluation.
* This may result in a service event of type MODIFIED_ENDMATCH.
*
* @param delivered The service event delivered by the framework.
* @return The event to be delivered or null if no event is to be delivered to the listener.
*/
private ServiceEvent filterMatch(ServiceEvent delivered) {
boolean modified = delivered.getType() == ServiceEvent.MODIFIED;
ServiceEvent event = modified ? ((ModifiedServiceEvent) delivered).getModifiedEvent() : delivered;
if (filter == null) {
return event;
}
ServiceReference<?> reference = event.getServiceReference();
if (filter.match(reference)) {
return event;
}
if (modified) {
ModifiedServiceEvent modifiedServiceEvent = (ModifiedServiceEvent) delivered;
if (modifiedServiceEvent.matchPreviousProperties(filter)) {
return modifiedServiceEvent.getModifiedEndMatchEvent();
}
}
// does not match and did not match previous properties; do not send event
return null;
}
/**
* The string representation of this Filtered listener.
*
* @return The string representation of this listener.
*/
public String toString() {
String filterString = getFilter();
if (filterString == null) {
filterString = ""; //$NON-NLS-1$
}
return listener.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(listener)) + filterString; //$NON-NLS-1$
}
/**
* Return the bundle context for the ListenerHook.
* @return The context of the bundle which added the service listener.
* @see org.osgi.framework.hooks.service.ListenerHook.ListenerInfo#getBundleContext()
*/
public BundleContext getBundleContext() {
return context;
}
/**
* Return the filter string for the ListenerHook.
* @return The filter string with which the listener was added. This may
* be <code>null</code> if the listener was added without a filter.
* @see org.osgi.framework.hooks.service.ListenerHook.ListenerInfo#getFilter()
*/
public String getFilter() {
if (filter != null) {
return filter.toString();
}
return getObjectClassFilterString(objectClass);
}
/**
* Return the state of the listener for this addition and removal life
* cycle. Initially this method will return <code>false</code>
* indicating the listener has been added but has not been removed.
* After the listener has been removed, this method must always return
* <code>true</code>.
*
* @return <code>false</code> if the listener has not been been removed,
* <code>true</code> otherwise.
*/
public boolean isRemoved() {
return removed;
}
/**
* Mark the service listener registration as removed.
*/
void markRemoved() {
removed = true;
}
/**
* Returns an objectClass filter string for the specified class name.
* @return A filter string for the specified class name or <code>null</code> if the
* specified class name is <code>null</code>.
*/
private static String getObjectClassFilterString(String className) {
if (className == null) {
return null;
}
return "(" + Constants.OBJECTCLASS + "=" + className + ")"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
}
}