org.eclipse.cdt.debug.edc/src/org/eclipse/cdt/debug/edc/services/EDCServicesTracker.java - gerrit/cdt/org.eclipse.cdt.edc - Git at Google

 /*******************************************************************************
  * Copyright (c) 2009, 2010 Wind River Systems 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:
  *     Wind River Systems - initial API and implementation
  *******************************************************************************/
 package org.eclipse.cdt.debug.edc.services;

 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;

 import org.eclipse.cdt.dsf.service.DsfSession;
 import org.eclipse.cdt.dsf.service.IDsfService;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.InvalidSyntaxException;
 import org.osgi.framework.ServiceEvent;
 import org.osgi.framework.ServiceListener;
 import org.osgi.framework.ServiceReference;

 @SuppressWarnings("rawtypes")

 /**
  * Convenience class to help track DSF services that a given
  * client needs to use.  This class is based on the DsfServicesTracker
  * but is designed to be thread safe so clients can use it to get
  * a service reference from any thread. This is important for EDC
  * services because they are not restricted to the Dsf thread.
  *
  * @since 2.0
  */
 public class EDCServicesTracker {

     private static String getServiceFilter(String sessionId) {
         return ("(" + IDsfService.PROP_SESSION_ID + "=" + sessionId + ")").intern();   //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
     }

     final private static class ServiceKey
     {
         private final String fClassName;
         private final String fFilter;
         private final int fHashCode;
         private final String fHashString;


         public ServiceKey(Class<?> clazz, String filter) {
             fClassName = clazz != null ? clazz.getName() : null;
             fFilter = filter;
             fHashString =  'C' + (fClassName == null ? "" : fClassName) + //$NON-NLS-1$
         				   'F' + (fFilter == null ? "" : fFilter); //$NON-NLS-1$
             fHashCode = fHashString.hashCode();
         }

         @Override
         public boolean equals(Object other) {
         	// hashcodes are not guaranteed to be unique, but objects that are equal must have the same hashcode
         	// thus we can optimize by first comparing hashcodes
             return other instanceof ServiceKey &&
             	((((ServiceKey)other).fHashCode == this.fHashCode) && (((ServiceKey)other).fHashString.equals(this.fHashString)));
         }

         @Override
         public int hashCode() {
         	return fHashCode;
         }
     }

     private final String fSessionId;
     private volatile boolean fDisposed = false;
     private final BundleContext fBundleContext;

 	private final Map<ServiceKey,ServiceReference> fServiceReferences = Collections.synchronizedMap(new HashMap<ServiceKey,ServiceReference>());
 	private final Map<ServiceReference,Object> fServices = Collections.synchronizedMap(new HashMap<ServiceReference,Object>());
     private final String fServiceFilter;

     private final ServiceListener fListner = new ServiceListener() {
         public void serviceChanged(final ServiceEvent event) {
             // Only listen to unregister events.
             if (event.getType() != ServiceEvent.UNREGISTERING) {
                 return;
             }

             // If session is not active anymore, just exit.  The tracker should
             // soon be disposed.
             DsfSession session = DsfSession.getSession(fSessionId);
             if (session == null) {
                 return;
             }

             handleUnregisterEvent(event);
         }
     };

 	private void handleUnregisterEvent(ServiceEvent event) {
     	synchronized (fServiceReferences)
     	{
             for (Iterator<Map.Entry<ServiceKey, ServiceReference>> itr = fServiceReferences.entrySet().iterator(); itr.hasNext();) {
                 Map.Entry<ServiceKey, ServiceReference> entry = itr.next();
                 if ( entry.getValue().equals(event.getServiceReference()) ) {
                     itr.remove();
                 }
             }
             if (fServices.remove(event.getServiceReference()) != null) {
                 fBundleContext.ungetService(event.getServiceReference());
             }
     	}
     }

     /**
      * Only constructor.
      * @param bundleContext Context of the plugin that the client lives in.
      * @param sessionId The DSF session that this tracker will be used for.
      */
     public EDCServicesTracker(BundleContext bundleContext, String sessionId) {
         fSessionId = sessionId;
         fBundleContext = bundleContext;
         fServiceFilter = getServiceFilter(sessionId);
         try {
             fBundleContext.addServiceListener(fListner, fServiceFilter);
         } catch (InvalidSyntaxException e) {
             assert false : "Invalid session ID syntax"; //$NON-NLS-1$
         }
     }

     /**
      * Retrieves a service reference for given service class and optional filter.
      * Filter should be used if there are multiple instances of the desired service
      * running within the same session.
      * @param serviceClass class of the desired service
      * @param custom filter to use when searching for the service, this filter will
      * be used instead of the standard filter so it should also specify the desired
      * session-ID
      * @return OSGI service reference object to the desired service, null if not found
      */
     public ServiceReference getServiceReference(Class serviceClass, String filter) {
         if (fDisposed) {
             return null;
         }

         // If the session is not active, all of its services are gone.
         DsfSession session = DsfSession.getSession(fSessionId);
         if (session == null) {
             return null;
         }

         ServiceKey key = new ServiceKey(serviceClass, filter != null ? filter : fServiceFilter);
         if (fServiceReferences.containsKey(key)) {
             return fServiceReferences.get(key);
         }

         try {
             ServiceReference[] references = fBundleContext.getServiceReferences(key.fClassName, key.fFilter);
             assert references == null || references.length <= 1;
             if (references == null || references.length == 0) {
                 return null;
             } else {
                 fServiceReferences.put(key, references[0]);
                 return references[0];
             }
         } catch(InvalidSyntaxException e) {
             assert false : "Invalid session ID syntax"; //$NON-NLS-1$
         } catch(IllegalStateException e) {
             // Can occur when plugin is shutting down.
         }
         return null;
     }

     /**
      * Convenience class to retrieve a service based on class name only.
      * @param serviceClass class of the desired service
      * @return instance of the desired service, null if not found
      */
     public <V> V getService(Class<V> serviceClass) {
         return getService(serviceClass, null);
     }

     /**
      * Retrieves the service given service class and optional filter.
      * Filter should be used if there are multiple instances of the desired service
      * running within the same session.
      * @param serviceClass class of the desired service
      * @param custom filter to use when searching for the service, this filter will
      * be used instead of the standard filter so it should also specify the desired
      * session-ID
      * @return instance of the desired service, null if not found
      */
     @SuppressWarnings("unchecked")
 	public <V> V getService(Class<V> serviceClass, String filter) {
         ServiceReference serviceRef = getServiceReference(serviceClass, filter);
         if (serviceRef == null) {
             return null;
         } else {
             if (fServices.containsKey(serviceRef)) {
                 return (V)fServices.get(serviceRef);
             } else {
                 V service = (V)fBundleContext.getService(serviceRef);
                 fServices.put(serviceRef, service);
                 return service;
             }
         }
     }

     /**
      * Un-gets all the references held by this tracker.  Must be called
      * to avoid leaking OSGI service references.
      */
     public void dispose() {
         assert !fDisposed;
         fDisposed = true;
         doDispose();
     }

 	private void doDispose() {
     	synchronized (fServices)
     	{
             try {
                 fBundleContext.removeServiceListener(fListner);
                 for (Iterator<ServiceReference> itr = fServices.keySet().iterator(); itr.hasNext();) {
                     fBundleContext.ungetService(itr.next());
                 }
             } catch (IllegalStateException e) {
                 // May be thrown during shutdown (bug 293049).
             }
     	}
         fServices.clear();
         fServiceReferences.clear();
     }

     @Override
     protected void finalize() throws Throwable {
         assert fDisposed;
         super.finalize();
     }
 }
	/*******************************************************************************
	* Copyright (c) 2009, 2010 Wind River Systems 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:
	* Wind River Systems - initial API and implementation
	*******************************************************************************/
	package org.eclipse.cdt.debug.edc.services;

	import java.util.Collections;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.Map;

	import org.eclipse.cdt.dsf.service.DsfSession;
	import org.eclipse.cdt.dsf.service.IDsfService;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.InvalidSyntaxException;
	import org.osgi.framework.ServiceEvent;
	import org.osgi.framework.ServiceListener;
	import org.osgi.framework.ServiceReference;

	@SuppressWarnings("rawtypes")

	/**
	* Convenience class to help track DSF services that a given
	* client needs to use. This class is based on the DsfServicesTracker
	* but is designed to be thread safe so clients can use it to get
	* a service reference from any thread. This is important for EDC
	* services because they are not restricted to the Dsf thread.
	*
	* @since 2.0
	*/
	public class EDCServicesTracker {

	private static String getServiceFilter(String sessionId) {
	return ("(" + IDsfService.PROP_SESSION_ID + "=" + sessionId + ")").intern(); //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
	}

	final private static class ServiceKey
	{
	private final String fClassName;
	private final String fFilter;
	private final int fHashCode;
	private final String fHashString;


	public ServiceKey(Class<?> clazz, String filter) {
	fClassName = clazz != null ? clazz.getName() : null;
	fFilter = filter;
	fHashString = 'C' + (fClassName == null ? "" : fClassName) + //$NON-NLS-1$
	'F' + (fFilter == null ? "" : fFilter); //$NON-NLS-1$
	fHashCode = fHashString.hashCode();
	}

	@Override
	public boolean equals(Object other) {
	// hashcodes are not guaranteed to be unique, but objects that are equal must have the same hashcode
	// thus we can optimize by first comparing hashcodes
	return other instanceof ServiceKey &&
	((((ServiceKey)other).fHashCode == this.fHashCode) && (((ServiceKey)other).fHashString.equals(this.fHashString)));
	}

	@Override
	public int hashCode() {
	return fHashCode;
	}
	}

	private final String fSessionId;
	private volatile boolean fDisposed = false;
	private final BundleContext fBundleContext;

	private final Map<ServiceKey,ServiceReference> fServiceReferences = Collections.synchronizedMap(new HashMap<ServiceKey,ServiceReference>());
	private final Map<ServiceReference,Object> fServices = Collections.synchronizedMap(new HashMap<ServiceReference,Object>());
	private final String fServiceFilter;

	private final ServiceListener fListner = new ServiceListener() {
	public void serviceChanged(final ServiceEvent event) {
	// Only listen to unregister events.
	if (event.getType() != ServiceEvent.UNREGISTERING) {
	return;
	}

	// If session is not active anymore, just exit. The tracker should
	// soon be disposed.
	DsfSession session = DsfSession.getSession(fSessionId);
	if (session == null) {
	return;
	}

	handleUnregisterEvent(event);
	}
	};

	private void handleUnregisterEvent(ServiceEvent event) {
	synchronized (fServiceReferences)
	{
	for (Iterator<Map.Entry<ServiceKey, ServiceReference>> itr = fServiceReferences.entrySet().iterator(); itr.hasNext();) {
	Map.Entry<ServiceKey, ServiceReference> entry = itr.next();
	if ( entry.getValue().equals(event.getServiceReference()) ) {
	itr.remove();
	}
	}
	if (fServices.remove(event.getServiceReference()) != null) {
	fBundleContext.ungetService(event.getServiceReference());
	}
	}
	}

	/**
	* Only constructor.
	* @param bundleContext Context of the plugin that the client lives in.
	* @param sessionId The DSF session that this tracker will be used for.
	*/
	public EDCServicesTracker(BundleContext bundleContext, String sessionId) {
	fSessionId = sessionId;
	fBundleContext = bundleContext;
	fServiceFilter = getServiceFilter(sessionId);
	try {
	fBundleContext.addServiceListener(fListner, fServiceFilter);
	} catch (InvalidSyntaxException e) {
	assert false : "Invalid session ID syntax"; //$NON-NLS-1$
	}
	}

	/**
	* Retrieves a service reference for given service class and optional filter.
	* Filter should be used if there are multiple instances of the desired service
	* running within the same session.
	* @param serviceClass class of the desired service
	* @param custom filter to use when searching for the service, this filter will
	* be used instead of the standard filter so it should also specify the desired
	* session-ID
	* @return OSGI service reference object to the desired service, null if not found
	*/
	public ServiceReference getServiceReference(Class serviceClass, String filter) {
	if (fDisposed) {
	return null;
	}

	// If the session is not active, all of its services are gone.
	DsfSession session = DsfSession.getSession(fSessionId);
	if (session == null) {
	return null;
	}

	ServiceKey key = new ServiceKey(serviceClass, filter != null ? filter : fServiceFilter);
	if (fServiceReferences.containsKey(key)) {
	return fServiceReferences.get(key);
	}

	try {
	ServiceReference[] references = fBundleContext.getServiceReferences(key.fClassName, key.fFilter);
	assert references == null \|\| references.length <= 1;
	if (references == null \|\| references.length == 0) {
	return null;
	} else {
	fServiceReferences.put(key, references[0]);
	return references[0];
	}
	} catch(InvalidSyntaxException e) {
	assert false : "Invalid session ID syntax"; //$NON-NLS-1$
	} catch(IllegalStateException e) {
	// Can occur when plugin is shutting down.
	}
	return null;
	}

	/**
	* Convenience class to retrieve a service based on class name only.
	* @param serviceClass class of the desired service
	* @return instance of the desired service, null if not found
	*/
	public <V> V getService(Class<V> serviceClass) {
	return getService(serviceClass, null);
	}

	/**
	* Retrieves the service given service class and optional filter.
	* Filter should be used if there are multiple instances of the desired service
	* running within the same session.
	* @param serviceClass class of the desired service
	* @param custom filter to use when searching for the service, this filter will
	* be used instead of the standard filter so it should also specify the desired
	* session-ID
	* @return instance of the desired service, null if not found
	*/
	@SuppressWarnings("unchecked")
	public <V> V getService(Class<V> serviceClass, String filter) {
	ServiceReference serviceRef = getServiceReference(serviceClass, filter);
	if (serviceRef == null) {
	return null;
	} else {
	if (fServices.containsKey(serviceRef)) {
	return (V)fServices.get(serviceRef);
	} else {
	V service = (V)fBundleContext.getService(serviceRef);
	fServices.put(serviceRef, service);
	return service;
	}
	}
	}

	/**
	* Un-gets all the references held by this tracker. Must be called
	* to avoid leaking OSGI service references.
	*/
	public void dispose() {
	assert !fDisposed;
	fDisposed = true;
	doDispose();
	}

	private void doDispose() {
	synchronized (fServices)
	{
	try {
	fBundleContext.removeServiceListener(fListner);
	for (Iterator<ServiceReference> itr = fServices.keySet().iterator(); itr.hasNext();) {
	fBundleContext.ungetService(itr.next());
	}
	} catch (IllegalStateException e) {
	// May be thrown during shutdown (bug 293049).
	}
	}
	fServices.clear();
	fServiceReferences.clear();
	}

	@Override
	protected void finalize() throws Throwable {
	assert fDisposed;
	super.finalize();
	}
	}