package org.apache.felix.dm.tracker;
/*
* Copyright (c) OSGi Alliance (2000, 2009). All Rights Reserved.
*
* 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.
*/
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeSet;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.felix.dm.impl.ServiceUtil;
import org.osgi.framework.AllServiceListener;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;
import org.osgi.framework.Filter;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceEvent;
import org.osgi.framework.ServiceListener;
import org.osgi.framework.ServiceReference;
import org.osgi.framework.Version;
/**
* The <code>ServiceTracker</code> class simplifies using services from the
* Framework's service registry.
* <p>
* A <code>ServiceTracker</code> object is constructed with search criteria and
* a <code>ServiceTrackerCustomizer</code> object. A <code>ServiceTracker</code>
* can use a <code>ServiceTrackerCustomizer</code> to customize the service
* objects to be tracked. The <code>ServiceTracker</code> can then be opened to
* begin tracking all services in the Framework's service registry that match
* the specified search criteria. The <code>ServiceTracker</code> correctly
* handles all of the details of listening to <code>ServiceEvent</code>s and
* getting and ungetting services.
* <p>
* The <code>getServiceReferences</code> method can be called to get references
* to the services being tracked. The <code>getService</code> and
* <code>getServices</code> methods can be called to get the service objects for
* the tracked service.
* <p>
* The <code>ServiceTracker</code> class is thread-safe. It does not call a
* <code>ServiceTrackerCustomizer</code> while holding any locks.
* <code>ServiceTrackerCustomizer</code> implementations must also be
* thread-safe.
*
* @ThreadSafe
* @version $Revision: 6386 $
*/
@SuppressWarnings("rawtypes")
public class ServiceTracker implements ServiceTrackerCustomizer {
/* set this to true to compile in debug messages */
static final boolean DEBUG = false;
/**
* The Bundle Context used by this <code>ServiceTracker</code>.
*/
protected final BundleContext context;
/**
* The Filter used by this <code>ServiceTracker</code> which specifies the
* search criteria for the services to track.
*
* @since 1.1
*/
protected final Filter filter;
/**
* The <code>ServiceTrackerCustomizer</code> for this tracker.
*/
final ServiceTrackerCustomizer customizer;
/**
* Filter string for use when adding the ServiceListener. If this field is
* set, then certain optimizations can be taken since we don't have a user
* supplied filter.
*/
final String listenerFilter;
/**
* Class name to be tracked. If this field is set, then we are tracking by
* class name.
*/
private final String trackClass;
/**
* Reference to be tracked. If this field is set, then we are tracking a
* single ServiceReference.
*/
private final ServiceReference trackReference;
/**
* Tracked services: <code>ServiceReference</code> -> customized Object and
* <code>ServiceListener</code> object
*/
private volatile Tracked tracked;
/**
* Accessor method for the current Tracked object. This method is only
* intended to be used by the unsynchronized methods which do not modify the
* tracked field.
*
* @return The current Tracked object.
*/
private Tracked tracked() {
return tracked;
}
/**
* Cached ServiceReference for getServiceReference.
*
* This field is volatile since it is accessed by multiple threads.
*/
private volatile ServiceReference cachedReference;
/**
* Cached service object for getService.
*
* This field is volatile since it is accessed by multiple threads.
*/
private volatile Object cachedService;
/**
* org.osgi.framework package version which introduced
* {@link ServiceEvent#MODIFIED_ENDMATCH}
*/
private static final Version endMatchVersion = new Version(1, 5, 0);
/**
* Flag that gets set when opening the tracker, determines if the tracker should
* track all aspects or just the highest ranked ones.
*/
public boolean m_trackAllAspects;
private boolean debug = false;
private String debugKey;
public void setDebug(String debugKey) {
this.debug = true;
this.debugKey = debugKey;
}
/**
* Create a <code>ServiceTracker</code> on the specified
* <code>ServiceReference</code>.
*
* <p>
* The service referenced by the specified <code>ServiceReference</code>
* will be tracked by this <code>ServiceTracker</code>.
*
* @param context The <code>BundleContext</code> against which the tracking
* is done.
* @param reference The <code>ServiceReference</code> for the service to be
* tracked.
* @param customizer The customizer object to call when services are added,
* modified, or removed in this <code>ServiceTracker</code>. If
* customizer is <code>null</code>, then this
* <code>ServiceTracker</code> will be used as the
* <code>ServiceTrackerCustomizer</code> and this
* <code>ServiceTracker</code> will call the
* <code>ServiceTrackerCustomizer</code> methods on itself.
*/
public ServiceTracker(final BundleContext context,
final ServiceReference reference,
final ServiceTrackerCustomizer customizer) {
this.context = context;
this.trackReference = reference;
this.trackClass = null;
this.customizer = (customizer == null) ? this : customizer;
this.listenerFilter = "(" + Constants.SERVICE_ID + "="
+ reference.getProperty(Constants.SERVICE_ID).toString() + ")";
try {
this.filter = context.createFilter(listenerFilter);
}
catch (InvalidSyntaxException e) {
/*
* we could only get this exception if the ServiceReference was
* invalid
*/
IllegalArgumentException iae = new IllegalArgumentException(
"unexpected InvalidSyntaxException: " + e.getMessage());
iae.initCause(e);
throw iae;
}
}
/**
* Create a <code>ServiceTracker</code> on the specified class name.
*
* <p>
* Services registered under the specified class name will be tracked by
* this <code>ServiceTracker</code>.
*
* @param context The <code>BundleContext</code> against which the tracking
* is done.
* @param clazz The class name of the services to be tracked.
* @param customizer The customizer object to call when services are added,
* modified, or removed in this <code>ServiceTracker</code>. If
* customizer is <code>null</code>, then this
* <code>ServiceTracker</code> will be used as the
* <code>ServiceTrackerCustomizer</code> and this
* <code>ServiceTracker</code> will call the
* <code>ServiceTrackerCustomizer</code> methods on itself.
*/
public ServiceTracker(final BundleContext context, final String clazz,
final ServiceTrackerCustomizer customizer) {
this.context = context;
this.trackReference = null;
this.trackClass = clazz;
this.customizer = (customizer == null) ? this : customizer;
// we call clazz.toString to verify clazz is non-null!
this.listenerFilter = "(" + Constants.OBJECTCLASS + "="
+ clazz.toString() + ")";
try {
this.filter = context.createFilter(listenerFilter);
}
catch (InvalidSyntaxException e) {
/*
* we could only get this exception if the clazz argument was
* malformed
*/
IllegalArgumentException iae = new IllegalArgumentException(
"unexpected InvalidSyntaxException: " + e.getMessage());
iae.initCause(e);
throw iae;
}
}
/**
* Create a <code>ServiceTracker</code> on the specified <code>Filter</code>
* object.
*
* <p>
* Services which match the specified <code>Filter</code> object will be
* tracked by this <code>ServiceTracker</code>.
*
* @param context The <code>BundleContext</code> against which the tracking
* is done.
* @param filter The <code>Filter</code> to select the services to be
* tracked.
* @param customizer The customizer object to call when services are added,
* modified, or removed in this <code>ServiceTracker</code>. If
* customizer is null, then this <code>ServiceTracker</code> will be
* used as the <code>ServiceTrackerCustomizer</code> and this
* <code>ServiceTracker</code> will call the
* <code>ServiceTrackerCustomizer</code> methods on itself.
* @since 1.1
*/
public ServiceTracker(final BundleContext context, final Filter filter,
final ServiceTrackerCustomizer customizer) {
this.context = context;
this.trackReference = null;
this.trackClass = null;
final Version frameworkVersion = (Version) AccessController
.doPrivileged(new PrivilegedAction<Version>() {
public Version run() {
String version = context
.getProperty(Constants.FRAMEWORK_VERSION);
return (version == null) ? Version.emptyVersion
: new Version(version);
}
});
final boolean endMatchSupported = (frameworkVersion
.compareTo(endMatchVersion) >= 0);
this.listenerFilter = endMatchSupported ? filter.toString() : null;
this.filter = filter;
this.customizer = (customizer == null) ? this : customizer;
if ((context == null) || (filter == null)) {
/*
* we throw a NPE here to be consistent with the other constructors
*/
throw new NullPointerException();
}
}
/**
* Open this <code>ServiceTracker</code> and begin tracking services.
*
* <p>
* This implementation calls <code>open(false)</code>.
*
* @throws java.lang.IllegalStateException If the <code>BundleContext</code>
* with which this <code>ServiceTracker</code> was created is no
* longer valid.
* @see #open(boolean)
*/
public void open() {
open(false);
}
/**
* Open this <code>ServiceTracker</code> and begin tracking services.
*
* <p>
* Services which match the search criteria specified when this
* <code>ServiceTracker</code> was created are now tracked by this
* <code>ServiceTracker</code>.
*
* @param trackAllServices If <code>true</code>, then this
* <code>ServiceTracker</code> will track all matching services
* regardless of class loader accessibility. If <code>false</code>,
* then this <code>ServiceTracker</code> will only track matching
* services which are class loader accessible to the bundle whose
* <code>BundleContext</code> is used by this
* <code>ServiceTracker</code>.
* @throws java.lang.IllegalStateException If the <code>BundleContext</code>
* with which this <code>ServiceTracker</code> was created is no
* longer valid.
* @since 1.3
*/
public void open(boolean trackAllServices) {
open(trackAllServices, false);
}
/**
* Open this <code>ServiceTracker</code> and begin tracking services.
*
* <p>
* Services which match the search criteria specified when this
* <code>ServiceTracker</code> was created are now tracked by this
* <code>ServiceTracker</code>.
*
* @param trackAllServices If <code>true</code>, then this
* <code>ServiceTracker</code> will track all matching services
* regardless of class loader accessibility. If <code>false</code>,
* then this <code>ServiceTracker</code> will only track matching
* services which are class loader accessible to the bundle whose
* <code>BundleContext</code> is used by this
* <code>ServiceTracker</code>.
* @param trackAllAspects If <code>true</code> then this
* <code>ServiceTracker</code> will track all aspects regardless
* of their rank. If <code>false</code> only the highest ranked
* aspects (or the original service if there are no aspects) will
* be tracked. The latter is the default.
* @throws java.lang.IllegalStateException If the <code>BundleContext</code>
* with which this <code>ServiceTracker</code> was created is no
* longer valid.
*/
public void open(boolean trackAllServices, boolean trackAllAspects) {
if (debug) {
System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " open");
}
final Tracked t;
synchronized (this) {
if (tracked != null) {
return;
}
if (DEBUG) {
System.out.println("ServiceTracker.open: " + filter);
}
m_trackAllAspects = trackAllAspects;
t = trackAllServices ? new AllTracked() : new Tracked();
synchronized (t) {
try {
context.addServiceListener(t, listenerFilter);
ServiceReference[] references = null;
if (trackClass != null) {
references = getInitialReferences(trackAllServices,
trackClass, null);
}
else {
if (trackReference != null) {
if (trackReference.getBundle() != null) {
references = new ServiceReference[] {trackReference};
}
}
else { /* user supplied filter */
references = getInitialReferences(trackAllServices,
null,
(listenerFilter != null) ? listenerFilter
: filter.toString());
}
}
/* set tracked with the initial references */
t.setInitial(references);
// only actually schedules the actions for execution within this synchronized block,
// but do the actual execution afterwards.
t.trackInitial();
}
catch (InvalidSyntaxException e) {
throw new RuntimeException(
"unexpected InvalidSyntaxException: "
+ e.getMessage(), e);
}
}
tracked = t;
}
/* Call tracked outside of synchronized region */
// just trigger the executor
t.getExecutor().execute();
}
/**
* Returns the list of initial <code>ServiceReference</code>s that will be
* tracked by this <code>ServiceTracker</code>.
*
* @param trackAllServices If <code>true</code>, use
* <code>getAllServiceReferences</code>.
* @param className The class name with which the service was registered, or
* <code>null</code> for all services.
* @param filterString The filter criteria or <code>null</code> for all
* services.
* @return The list of initial <code>ServiceReference</code>s.
* @throws InvalidSyntaxException If the specified filterString has an
* invalid syntax.
*/
private ServiceReference[] getInitialReferences(boolean trackAllServices,
String className, String filterString)
throws InvalidSyntaxException {
if (trackAllServices) {
return context.getAllServiceReferences(className, filterString);
}
return context.getServiceReferences(className, filterString);
}
/**
* Close this <code>ServiceTracker</code>.
*
* <p>
* This method should be called when this <code>ServiceTracker</code> should
* end the tracking of services.
*
* <p>
* This implementation calls {@link #getServiceReferences()} to get the list
* of tracked services to remove.
*/
public void close() {
final Tracked outgoing;
final ServiceReference[] references;
synchronized (this) {
outgoing = tracked;
if (outgoing == null) {
return;
}
if (DEBUG) {
System.out.println("ServiceTracker.close: " + filter);
}
outgoing.close();
references = getServiceReferences();
tracked = null;
try {
context.removeServiceListener(outgoing);
}
catch (IllegalStateException e) {
/* In case the context was stopped. */
}
}
modified(); /* clear the cache */
synchronized (outgoing) {
outgoing.notifyAll(); /* wake up any waiters */
}
if (references != null) {
for (int i = 0; i < references.length; i++) {
outgoing.untrack(references[i], null).execute();
}
}
if (DEBUG) {
if ((cachedReference == null) && (cachedService == null)) {
System.out
.println("ServiceTracker.close[cached cleared]: "
+ filter);
}
}
}
/**
* Default implementation of the
* <code>ServiceTrackerCustomizer.addingService</code> method.
*
* <p>
* This method is only called when this <code>ServiceTracker</code> has been
* constructed with a <code>null ServiceTrackerCustomizer</code> argument.
*
* <p>
* This implementation returns the result of calling <code>getService</code>
* on the <code>BundleContext</code> with which this
* <code>ServiceTracker</code> was created passing the specified
* <code>ServiceReference</code>.
* <p>
* This method can be overridden in a subclass to customize the service
* object to be tracked for the service being added. In that case, take care
* not to rely on the default implementation of
* {@link #removedService(ServiceReference, Object) removedService} to unget
* the service.
*
* @param reference The reference to the service being added to this
* <code>ServiceTracker</code>.
* @return The service object to be tracked for the service added to this
* <code>ServiceTracker</code>.
* @see ServiceTrackerCustomizer#addingService(ServiceReference)
*/
@SuppressWarnings("unchecked")
public Object addingService(ServiceReference reference) {
return context.getService(reference);
}
public void addedService(ServiceReference reference, Object service) {
/* do nothing */
}
/**
* Default implementation of the
* <code>ServiceTrackerCustomizer.modifiedService</code> method.
*
* <p>
* This method is only called when this <code>ServiceTracker</code> has been
* constructed with a <code>null ServiceTrackerCustomizer</code> argument.
*
* <p>
* This implementation does nothing.
*
* @param reference The reference to modified service.
* @param service The service object for the modified service.
* @see ServiceTrackerCustomizer#modifiedService(ServiceReference, Object)
*/
public void modifiedService(ServiceReference reference, Object service) {
/* do nothing */
}
/**
* Default implementation of the
* <code>ServiceTrackerCustomizer.removedService</code> method.
*
* <p>
* This method is only called when this <code>ServiceTracker</code> has been
* constructed with a <code>null ServiceTrackerCustomizer</code> argument.
*
* <p>
* This implementation calls <code>ungetService</code>, on the
* <code>BundleContext</code> with which this <code>ServiceTracker</code>
* was created, passing the specified <code>ServiceReference</code>.
* <p>
* This method can be overridden in a subclass. If the default
* implementation of {@link #addingService(ServiceReference) addingService}
* method was used, this method must unget the service.
*
* @param reference The reference to removed service.
* @param service The service object for the removed service.
* @see ServiceTrackerCustomizer#removedService(ServiceReference, Object)
*/
public void removedService(ServiceReference reference, Object service) {
context.ungetService(reference);
}
/**
* Wait for at least one service to be tracked by this
* <code>ServiceTracker</code>. This method will also return when this
* <code>ServiceTracker</code> is closed.
*
* <p>
* It is strongly recommended that <code>waitForService</code> is not used
* during the calling of the <code>BundleActivator</code> methods.
* <code>BundleActivator</code> methods are expected to complete in a short
* period of time.
*
* <p>
* This implementation calls {@link #getService()} to determine if a service
* is being tracked.
*
* @param timeout The time interval in milliseconds to wait. If zero, the
* method will wait indefinitely.
* @return Returns the result of {@link #getService()}.
* @throws InterruptedException If another thread has interrupted the
* current thread.
* @throws IllegalArgumentException If the value of timeout is negative.
*/
public Object waitForService(long timeout) throws InterruptedException {
if (timeout < 0) {
throw new IllegalArgumentException("timeout value is negative");
}
Object object = getService();
while (object == null) {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return null;
}
synchronized (t) {
if (t.size() == 0) {
t.wait(timeout);
}
}
object = getService();
if (timeout > 0) {
return object;
}
}
return object;
}
/**
* Return an array of <code>ServiceReference</code>s for all services being
* tracked by this <code>ServiceTracker</code>.
*
* @return Array of <code>ServiceReference</code>s or <code>null</code> if
* no services are being tracked.
*/
public ServiceReference[] getServiceReferences() {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return null;
}
synchronized (t) {
int length = t.size();
if (length == 0) {
return null;
}
return (ServiceReference[]) t
.getTracked(new ServiceReference[length]);
}
}
/**
* Returns a boolean indicating whether this <code>ServiceTracker</code> is tracking any services.
*
* @return true if services are being tracked, false if no services are being tracked.
*/
public boolean hasReference() {
if (cachedReference != null) {
return true;
}
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return false;
}
synchronized (t) {
int length = t.size();
return length > 0;
}
}
/**
* Returns a <code>ServiceReference</code> for one of the services being
* tracked by this <code>ServiceTracker</code>.
*
* <p>
* If multiple services are being tracked, the service with the highest
* ranking (as specified in its <code>service.ranking</code> property) is
* returned. If there is a tie in ranking, the service with the lowest
* service ID (as specified in its <code>service.id</code> property); that
* is, the service that was registered first is returned. This is the same
* algorithm used by <code>BundleContext.getServiceReference</code>.
*
* <p>
* This implementation calls {@link #getServiceReferences()} to get the list
* of references for the tracked services.
*
* @return A <code>ServiceReference</code> or <code>null</code> if no
* services are being tracked.
* @since 1.1
*/
public ServiceReference getServiceReference() {
ServiceReference reference = cachedReference;
if (reference != null) {
if (DEBUG) {
System.out
.println("ServiceTracker.getServiceReference[cached]: "
+ filter);
}
return reference;
}
if (DEBUG) {
System.out.println("ServiceTracker.getServiceReference: " + filter);
}
ServiceReference[] references = getServiceReferences();
int length = (references == null) ? 0 : references.length;
if (length == 0) { /* if no service is being tracked */
return null;
}
int index = 0;
if (length > 1) { /* if more than one service, select highest ranking */
int rankings[] = new int[length];
int count = 0;
int maxRanking = Integer.MIN_VALUE;
for (int i = 0; i < length; i++) {
Object property = references[i]
.getProperty(Constants.SERVICE_RANKING);
int ranking = (property instanceof Integer) ? ((Integer) property)
.intValue()
: 0;
rankings[i] = ranking;
if (ranking > maxRanking) {
index = i;
maxRanking = ranking;
count = 1;
}
else {
if (ranking == maxRanking) {
count++;
}
}
}
if (count > 1) { /* if still more than one service, select lowest id */
long minId = Long.MAX_VALUE;
for (int i = 0; i < length; i++) {
if (rankings[i] == maxRanking) {
long id = ((Long) (references[i]
.getProperty(Constants.SERVICE_ID)))
.longValue();
if (id < minId) {
index = i;
minId = id;
}
}
}
}
}
return cachedReference = references[index];
}
/**
* Returns the service object for the specified
* <code>ServiceReference</code> if the specified referenced service is
* being tracked by this <code>ServiceTracker</code>.
*
* @param reference The reference to the desired service.
* @return A service object or <code>null</code> if the service referenced
* by the specified <code>ServiceReference</code> is not being
* tracked.
*/
public Object getService(ServiceReference reference) {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return null;
}
synchronized (t) {
return t.getCustomizedObject(reference);
}
}
/**
* Return an array of service objects for all services being tracked by this
* <code>ServiceTracker</code>.
*
* <p>
* This implementation calls {@link #getServiceReferences()} to get the list
* of references for the tracked services and then calls
* {@link #getService(ServiceReference)} for each reference to get the
* tracked service object.
*
* @return An array of service objects or <code>null</code> if no services
* are being tracked.
*/
public Object[] getServices() {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return null;
}
synchronized (t) {
ServiceReference[] references = getServiceReferences();
int length = (references == null) ? 0 : references.length;
if (length == 0) {
return null;
}
Object[] objects = new Object[length];
for (int i = 0; i < length; i++) {
objects[i] = getService(references[i]);
}
return objects;
}
}
/**
* Returns a service object for one of the services being tracked by this
* <code>ServiceTracker</code>.
*
* <p>
* If any services are being tracked, this implementation returns the result
* of calling <code>getService(getServiceReference())</code>.
*
* @return A service object or <code>null</code> if no services are being
* tracked.
*/
public Object getService() {
Object service = cachedService;
if (service != null) {
if (DEBUG) {
System.out
.println("ServiceTracker.getService[cached]: "
+ filter);
}
return service;
}
if (DEBUG) {
System.out.println("ServiceTracker.getService: " + filter);
}
ServiceReference reference = getServiceReference();
if (reference == null) {
return null;
}
return cachedService = getService(reference);
}
/**
* Remove a service from this <code>ServiceTracker</code>.
*
* The specified service will be removed from this
* <code>ServiceTracker</code>. If the specified service was being tracked
* then the <code>ServiceTrackerCustomizer.removedService</code> method will
* be called for that service.
*
* @param reference The reference to the service to be removed.
*/
public void remove(ServiceReference reference) {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return;
}
t.untrack(reference, null).execute();
}
/**
* Return the number of services being tracked by this
* <code>ServiceTracker</code>.
*
* @return The number of services being tracked.
*/
public int size() {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return 0;
}
synchronized (t) {
return t.size();
}
}
/**
* Returns the tracking count for this <code>ServiceTracker</code>.
*
* The tracking count is initialized to 0 when this
* <code>ServiceTracker</code> is opened. Every time a service is added,
* modified or removed from this <code>ServiceTracker</code>, the tracking
* count is incremented.
*
* <p>
* The tracking count can be used to determine if this
* <code>ServiceTracker</code> has added, modified or removed a service by
* comparing a tracking count value previously collected with the current
* tracking count value. If the value has not changed, then no service has
* been added, modified or removed from this <code>ServiceTracker</code>
* since the previous tracking count was collected.
*
* @since 1.2
* @return The tracking count for this <code>ServiceTracker</code> or -1 if
* this <code>ServiceTracker</code> is not open.
*/
public int getTrackingCount() {
final Tracked t = tracked();
if (t == null) { /* if ServiceTracker is not open */
return -1;
}
synchronized (t) {
return t.getTrackingCount();
}
}
/**
* Called by the Tracked object whenever the set of tracked services is
* modified. Clears the cache.
*/
/*
* This method must not be synchronized since it is called by Tracked while
* Tracked is synchronized. We don't want synchronization interactions
* between the listener thread and the user thread.
*/
void modified() {
cachedReference = null; /* clear cached value */
cachedService = null; /* clear cached value */
if (DEBUG) {
System.out.println("ServiceTracker.modified: " + filter);
}
}
/**
* Inner class which subclasses AbstractTracked. This class is the
* <code>ServiceListener</code> object for the tracker.
*
* @ThreadSafe
*/
class Tracked extends AbstractTracked implements ServiceListener {
/**
* A list of services that are currently hidden because there is an aspect available with a higher ranking.
* @GuardedBy this
*/
private final Map<Long, TreeSet<ServiceReference>> m_highestTrackedCache = new HashMap<>();
private final Map<Long, TreeSet<ServiceReference>> m_highestHiddenCache = new HashMap<>();
private ServiceReference highestTrackedCache(long serviceId) {
Long sid = Long.valueOf(serviceId);
synchronized (this) {
TreeSet<ServiceReference> services = m_highestTrackedCache.get(sid);
if (services != null && services.size() > 0) {
ServiceReference result = (ServiceReference) services.last();
return result;
}
}
return null;
}
private void addHighestTrackedCache(ServiceReference reference) {
Long serviceId = ServiceUtil.getServiceIdObject(reference);
synchronized (this) {
TreeSet<ServiceReference> services = m_highestTrackedCache.get(serviceId);
if (services == null) {
services = new TreeSet<ServiceReference>();
m_highestTrackedCache.put(serviceId, services);
}
services.add(reference);
}
}
private void removeHighestTrackedCache(ServiceReference reference) {
Long serviceId = ServiceUtil.getServiceIdObject(reference);
synchronized (this) {
TreeSet<ServiceReference> services = m_highestTrackedCache.get(serviceId);
if (services != null) {
services.remove(reference);
}
}
}
private void clearHighestTrackedCache() {
synchronized (this) {
m_highestTrackedCache.clear();
}
}
private ServiceReference highestHiddenCache(long serviceId) {
Long sid = Long.valueOf(serviceId);
synchronized (this) {
TreeSet<ServiceReference> services = m_highestHiddenCache.get(sid);
if (services != null && services.size() > 0) {
ServiceReference result = (ServiceReference) services.last();
return result;
}
}
return null;
}
private void addHighestHiddenCache(ServiceReference reference) {
Long serviceId = ServiceUtil.getServiceIdObject(reference);
synchronized (this) {
TreeSet<ServiceReference> services = m_highestHiddenCache.get(serviceId);
if (services == null) {
services = new TreeSet<ServiceReference>();
m_highestHiddenCache.put(serviceId, services);
}
services.add(reference);
}
}
private void removeHighestHiddenCache(ServiceReference reference) {
Long serviceId = ServiceUtil.getServiceIdObject(reference);
synchronized (this) {
TreeSet<ServiceReference> services = m_highestHiddenCache.get(serviceId);
if (services != null) {
services.remove(reference);
}
}
}
/**
* Hide a service reference, placing it in the list of hidden services.
*
* @param ref the service reference to add to the hidden list
*/
private void hide(ServiceReference ref) {
addHighestHiddenCache(ref);
}
/**
* Unhide a service reference, removing it from the list of hidden services.
*
* @param ref the service reference to remove from the hidden list
*/
private void unhide(ServiceReference ref) {
removeHighestHiddenCache(ref);
}
/**
* Tracked constructor.
*/
Tracked() {
super();
setTracked(new HashMapCache<Object, Object>());
}
void setInitial(Object[] list) {
if (list == null) {
return;
}
if (m_trackAllAspects) {
// not hiding aspects
super.setInitial(list);
} else {
Map<Long, RankedService> highestRankedServiceMap = new HashMap<>();
for (int i = 0; i < list.length; i++) {
ServiceReference sr = (ServiceReference) list[i];
if (sr != null) {
Long serviceId = ServiceUtil.getServiceIdAsLong(sr);
int ranking = ServiceUtil.getRanking(sr);
RankedService rs = (RankedService) highestRankedServiceMap.get(serviceId);
if (rs == null) {
// the service did not exist yet in our map
highestRankedServiceMap.put(serviceId, new RankedService(ranking, sr));
}
else if (ranking > rs.getRanking()) {
// the service replaces a lower ranked one
hide(rs.getServiceReference());
rs.update(ranking, sr);
}
else {
// the service does NOT replace a lower ranked one
hide(sr);
}
}
}
if (highestRankedServiceMap.size() > 0) {
Object[] result = new Object[highestRankedServiceMap.size()];
int index = 0;
for(Iterator<Entry<Long, RankedService>> it = highestRankedServiceMap.entrySet().iterator(); it.hasNext(); ) {
Entry<Long, RankedService> entry = it.next();
result[index] = ((RankedService)entry.getValue()).getServiceReference();
index++;
}
super.setInitial(result);
}
}
}
/**
* <code>ServiceListener</code> method for the
* <code>ServiceTracker</code> class. This method must NOT be
* synchronized to avoid deadlock potential.
*
* @param event <code>ServiceEvent</code> object from the framework.
*/
public void serviceChanged(final ServiceEvent event) {
if (m_trackAllAspects) {
serviceChangedIncludeAspects(event);
}
else {
serviceChangedHideAspects(event);
}
}
public void serviceChangedIncludeAspects(final ServiceEvent event) {
/*
* Check if we had a delayed call (which could happen when we
* close).
*/
if (closed) {
return;
}
final ServiceReference reference = event.getServiceReference();
if (debug) {
System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " [serviceChangedIncludeAspects] " + reference.getProperty("service.ranking"));
}
if (DEBUG) {
System.out
.println("ServiceTracker.Tracked.serviceChanged["
+ event.getType() + "]: " + reference);
}
switch (event.getType()) {
case ServiceEvent.REGISTERED :
case ServiceEvent.MODIFIED :
if (listenerFilter != null) { // service listener added with
// filter
track(reference, event).execute();
/*
* If the customizer throws an unchecked exception, it
* is safe to let it propagate
*/
}
else { // service listener added without filter
if (filter.match(reference)) {
track(reference, event).execute();
/*
* If the customizer throws an unchecked exception,
* it is safe to let it propagate
*/
}
else {
untrack(reference, event).execute();
/*
* If the customizer throws an unchecked exception,
* it is safe to let it propagate
*/
}
}
break;
case 8 /* ServiceEvent.MODIFIED_ENDMATCH */ :
case ServiceEvent.UNREGISTERING :
untrack(reference, event).execute();
/*
* If the customizer throws an unchecked exception, it is
* safe to let it propagate
*/
break;
}
}
private boolean isModifiedEndmatchSupported() {
return listenerFilter != null;
}
private AtomicInteger step = new AtomicInteger();
public void serviceChangedHideAspects(final ServiceEvent event) {
int n = step.getAndIncrement();
/*
* Check if we had a delayed call (which could happen when we
* close).
*/
if (closed) {
return;
}
final ServiceReference reference = event.getServiceReference();
if (DEBUG) {
System.out
.println(n + " ServiceTracker.Tracked.serviceChanged["
+ event.getType() + "]: " + reference);
}
long sid = ServiceUtil.getServiceId(reference);
AbstractCustomizerActionSet actionSet = null;
synchronized(this) {
switch (event.getType()) {
case ServiceEvent.REGISTERED :
case ServiceEvent.MODIFIED :
ServiceReference higherRankedReference = null;
ServiceReference lowerRankedReference = null;
ServiceReference highestTrackedReference = highestTrackedCache(sid);
if (highestTrackedReference != null) {
int ranking = ServiceUtil.getRanking(reference);
int highestTrackedRanking = ServiceUtil.getRanking(highestTrackedReference);
if (ranking > highestTrackedRanking) {
// found a higher ranked one!
if (DEBUG) {
System.out.println("ServiceTracker.Tracked.serviceChanged[" + event.getType() + "]: Found a higher ranked aspect: " + ServiceUtil.toString(reference) + " vs " + ServiceUtil.toString(highestTrackedReference));
}
higherRankedReference = highestTrackedReference;
}
else if (ranking < highestTrackedRanking) {
// found lower ranked one!
if (DEBUG) {
System.out.println("ServiceTracker.Tracked.serviceChanged[" + event.getType() + "]: Found a lower ranked aspect: " + ServiceUtil.toString(reference) + " vs " + ServiceUtil.toString(highestTrackedReference));
}
lowerRankedReference = highestTrackedReference;
}
}
if (isModifiedEndmatchSupported()) { // either registered or modified
actionSet = registerOrUpdate(event, reference, higherRankedReference, lowerRankedReference);
}
else { // service listener added without filter
if (filter.match(reference)) {
actionSet = registerOrUpdate(event, reference, higherRankedReference, lowerRankedReference);
}
else {
actionSet = unregister(event, reference, sid);
}
}
break;
case 8 /* ServiceEvent.MODIFIED_ENDMATCH */ : // handle as unregister
case ServiceEvent.UNREGISTERING :
actionSet = unregister(event, reference, sid);
/*
* If the customizer throws an unchecked exception, it is
* safe to let it propagate
*/
break;
}
// schedule the actionset for execution. We'll use a serial executor to prevent the actions to
// be performed out of order.
final AbstractCustomizerActionSet commandActionSet = actionSet;
if (commandActionSet != null) {
getExecutor().schedule(new Runnable() {
@Override
public void run() {
commandActionSet.execute();
}
});
}
}
getExecutor().execute();
}
private AbstractCustomizerActionSet registerOrUpdate(final ServiceEvent event,
final ServiceReference reference, ServiceReference higher,
ServiceReference lower) {
if (debug) {
// System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " [registerOrUpdate] lower: " + lower + ", higher: " + higher);
}
AbstractCustomizerActionSet actionSet = null;
if (lower != null) {
hide(reference);
}
else {
actionSet = track(reference, event);
if (higher != null) {
actionSet.appendActionSet(untrack(higher, null));
hide(higher);
}
}
/*
* If the customizer throws an unchecked exception, it
* is safe to let it propagate
*/
return actionSet;
}
private AbstractCustomizerActionSet unregister(final ServiceEvent event,
final ServiceReference reference, long sid) {
if (debug) {
System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " [unregister] " + reference.getProperty("service.ranking"));
}
AbstractCustomizerActionSet actionSet = null;
ServiceReference ht = highestTrackedCache(sid);
if (reference.equals(ht)) {
ServiceReference hh = highestHiddenCache(sid);
if (hh != null) {
unhide(hh);
actionSet = track(hh, null);
}
if (actionSet == null) {
actionSet = untrack(reference, event);
} else {
actionSet.appendActionSet(untrack(reference, event));
}
}
else {
unhide(reference);
}
return actionSet;
}
/**
* Increment the tracking count and tell the tracker there was a
* modification.
*
* @GuardedBy this
*/
void modified() {
super.modified(); /* increment the modification count */
ServiceTracker.this.modified();
}
/**
* Call the specific customizer adding method. This method must not be
* called while synchronized on this object.
*
* @param item Item to be tracked.
* @param related Action related object.
* @return Customized object for the tracked item or <code>null</code>
* if the item is not to be tracked.
*/
Object customizerAdding(final Object item,
final Object related) {
return customizer.addingService((ServiceReference) item);
}
void customizerAdded(final Object item, final Object related, final Object object) {
customizer.addedService((ServiceReference) item, object);
}
/**
* Call the specific customizer modified method. This method must not be
* called while synchronized on this object.
*
* @param item Tracked item.
* @param related Action related object.
* @param object Customized object for the tracked item.
*/
void customizerModified(final Object item,
final Object related, final Object object) {
customizer.modifiedService((ServiceReference) item, object);
}
/**
* Call the specific customizer removed method. This method must not be
* called while synchronized on this object.
*
* @param item Tracked item.
* @param related Action related object.
* @param object Customized object for the tracked item.
*/
void customizerRemoved(final Object item,
final Object related, final Object object) {
customizer.removedService((ServiceReference) item, object);
}
class HashMapCache<K, V> extends LinkedHashMap<K, V> {
private static final long serialVersionUID = 1627005136730183946L;
public V put(K key, V value) {
addHighestTrackedCache((ServiceReference) key);
return super.put(key, value);
}
public void putAll(Map<? extends K, ? extends V> m) {
Iterator<? extends K> i = m.keySet().iterator();
while (i.hasNext()) {
addHighestTrackedCache((ServiceReference) i.next());
}
super.putAll(m);
}
public V remove(Object key) {
removeHighestTrackedCache((ServiceReference) key);
return super.remove(key);
}
public void clear() {
clearHighestTrackedCache();
super.clear();
}
}
@Override
AbstractCustomizerActionSet createCustomizerActionSet() {
// This actions set deliberately postpones invocation of the customizer methods to be able to combine added and removed
// into a single swap call.
return new AbstractCustomizerActionSet() {
@Override
public void addCustomizerAdded(Object item, Object related,
Object object) {
if (debug) {
// System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " addCustomizerAdded " + object);
}
super.addCustomizerAdded(item, related, object);
}
@Override
public void addCustomizerModified(Object item, Object related,
Object object) {
if (debug) {
// System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " addCustomizerModified " + object);
}
super.addCustomizerModified(item, related, object);
}
@Override
public void addCustomizerRemoved(Object item, Object related,
Object object) {
if (debug) {
// System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " addCustomizerRemoved " + object);
}
super.addCustomizerRemoved(item, related, object);
}
@Override
void execute() {
// inspect the actions and check whether we should perform a swap
List<CustomizerAction> actions = getActions();
if (actions.size() > 2) {
throw new IllegalStateException("Unexpected action count: " + actions.size());
}
if (actions.size() == 2 && actions.get(0).getType() == Type.ADDED && actions.get(1).getType() == Type.REMOVED) {
// ignore related
// item = ServiceReference
// object = service
debug("swapped");
if (debug) {
System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " swapping " + actions.get(1).getObject() + " with " + actions.get(0).getObject());
}
customizer.swappedService((ServiceReference)actions.get(1).getItem(), actions.get(1).getObject(), (ServiceReference)actions.get(0).getItem(), actions.get(0).getObject());
} else {
// just sequentially call the customizer methods
for (CustomizerAction action : getActions()) {
try {
switch (action.getType()) {
case ADDED:
debug(Thread.currentThread().getId() + " added");
if (debug) {
System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " adding " + action.getObject());
}
customizerAdded(action.getItem(), action.getRelated(), action.getObject());
break;
case MODIFIED:
debug("modified");
customizerModified(action.getItem(), action.getRelated(), action.getObject());
break;
case REMOVED:
debug("removed");
if (debug) {
System.out.println("[ServiceTracker] " + debugKey + " T" + Thread.currentThread().getId() + " removing " + action.getObject());
}
customizerRemoved(action.getItem(), action.getRelated(), action.getObject());
}
} catch (Exception e) {
// just continue. log messages will be printed elsewhere.
}
}
}
}
};
}
}
private void debug(String message) {
if (customizer.toString().equals("ServiceDependency[interface dm.it.AspectRaceTest$S (&(!(org.apache.felix.dependencymanager.aspect=*))(id=1))]")) {
// System.out.println(message);
}
}
/**
* Subclass of Tracked which implements the AllServiceListener interface.
* This class is used by the ServiceTracker if open is called with true.
*
* @since 1.3
* @ThreadSafe
*/
class AllTracked extends Tracked implements AllServiceListener {
/**
* AllTracked constructor.
*/
AllTracked() {
super();
setTracked(new HashMapCache<Object, Object>());
}
}
/**
* Holds a ranking and a service reference that can be updated if necessary.
*/
private static final class RankedService {
private int m_ranking;
private ServiceReference m_serviceReference;
public RankedService(int ranking, ServiceReference serviceReference) {
m_ranking = ranking;
m_serviceReference = serviceReference;
}
public void update(int ranking, ServiceReference serviceReference) {
m_ranking = ranking;
m_serviceReference = serviceReference;
}
public int getRanking() {
return m_ranking;
}
public ServiceReference getServiceReference() {
return m_serviceReference;
}
}
@Override
public void swappedService(ServiceReference reference, Object service,
ServiceReference newReference, Object newService) {
}
// Package private, used for unit testing Tracked
Tracked getTracked() {
return tracked;
}
}