| /* |
| * Copyright (c) OSGi Alliance (2000, 2012). 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. |
| */ |
| |
| package org.apache.felix.scr.impl.manager; |
| |
| import java.lang.reflect.Array; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.SortedMap; |
| import java.util.TreeMap; |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| 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; |
| |
| /** |
| * The {@code ServiceTracker} class simplifies using services from the |
| * Framework's service registry. |
| * <p> |
| * A {@code ServiceTracker} object is constructed with search criteria and a |
| * {@code ServiceTrackerCustomizer} object. A {@code ServiceTracker} can use a |
| * {@code ServiceTrackerCustomizer} to customize the service objects to be |
| * tracked. The {@code ServiceTracker} can then be opened to begin tracking all |
| * services in the Framework's service registry that match the specified search |
| * criteria. The {@code ServiceTracker} correctly handles all of the details of |
| * listening to {@code ServiceEvent}s and getting and ungetting services. |
| * <p> |
| * The {@code getServiceReferences} method can be called to get references to |
| * the services being tracked. The {@code getService} and {@code getServices} |
| * methods can be called to get the service objects for the tracked service. |
| * <p> |
| * The {@code ServiceTracker} class is thread-safe. It does not call a |
| * {@code ServiceTrackerCustomizer} while holding any locks. |
| * {@code ServiceTrackerCustomizer} implementations must also be thread-safe. |
| * |
| * @param <S> The type of the service being tracked. |
| * @param <T> The type of the tracked object. |
| * @ThreadSafe |
| * @version $Id: 21926ad8717a91633face6bbf570febfcd23b1c7 $ |
| */ |
| |
| /** |
| * changes from osgi service tracker: |
| * |
| * - included AbstractTracked as an inner class. |
| * - addedService method on customizer called after the object is tracked. |
| * - we always track all matching services. |
| * |
| * @param <S> |
| * @param <T> |
| */ |
| public class ServiceTracker<S, T> { |
| /* set this to true to compile in debug messages */ |
| static final boolean DEBUG = false; |
| /** |
| * The Bundle Context used by this {@code ServiceTracker}. |
| */ |
| protected final BundleContext context; |
| /** |
| * The Filter used by this {@code ServiceTracker} which specifies the search |
| * criteria for the services to track. |
| * |
| * @since 1.1 |
| */ |
| protected final Filter filter; |
| /** |
| * The {@code ServiceTrackerCustomizer} for this tracker. |
| */ |
| final ServiceTrackerCustomizer<S, T> 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<S> trackReference; |
| /** |
| * Tracked services: {@code ServiceReference} -> customized Object and |
| * {@code ServiceListener} object |
| */ |
| private volatile Tracked tracked; |
| |
| |
| /** |
| * whether the DependencyManager is getting the service immediately. |
| */ |
| private boolean active; |
| |
| /** |
| * 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. |
| */ |
| public Tracked tracked() { |
| return tracked; |
| } |
| |
| /** |
| * Cached ServiceReference for getServiceReference. |
| * |
| * This field is volatile since it is accessed by multiple threads. |
| */ |
| private volatile ServiceReference<S> cachedReference; |
| /** |
| * Cached service object for getService. |
| * |
| * This field is volatile since it is accessed by multiple threads. |
| */ |
| private volatile T cachedService; |
| |
| /** |
| * Create a {@code ServiceTracker} on the specified {@code ServiceReference} |
| * . |
| * |
| * <p> |
| * The service referenced by the specified {@code ServiceReference} will be |
| * tracked by this {@code ServiceTracker}. |
| * |
| * @param context The {@code BundleContext} against which the tracking is |
| * done. |
| * @param reference The {@code ServiceReference} for the service to be |
| * tracked. |
| * @param customizer The customizer object to call when services are added, |
| * modified, or removed in this {@code ServiceTracker}. If customizer |
| * is {@code null}, then this {@code ServiceTracker} will be used as |
| * the {@code ServiceTrackerCustomizer} and this |
| * {@code ServiceTracker} will call the |
| * {@code ServiceTrackerCustomizer} methods on itself. |
| */ |
| public ServiceTracker(final BundleContext context, final ServiceReference<S> reference, final ServiceTrackerCustomizer<S, T> customizer) { |
| this.context = context; |
| this.trackReference = reference; |
| this.trackClass = null; |
| this.customizer = 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} on the specified class name. |
| * |
| * <p> |
| * Services registered under the specified class name will be tracked by |
| * this {@code ServiceTracker}. |
| * |
| * @param context The {@code BundleContext} 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}. If customizer |
| * is {@code null}, then this {@code ServiceTracker} will be used as |
| * the {@code ServiceTrackerCustomizer} and this |
| * {@code ServiceTracker} will call the |
| * {@code ServiceTrackerCustomizer} methods on itself. |
| */ |
| public ServiceTracker(final BundleContext context, final String clazz, final ServiceTrackerCustomizer<S, T> customizer) { |
| this.context = context; |
| this.trackReference = null; |
| this.trackClass = clazz; |
| this.customizer = customizer; |
| // we call clazz.toString to verify clazz is non-null! |
| this.listenerFilter = "(" + Constants.OBJECTCLASS + "=" + clazz + ")"; |
| 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} on the specified {@code Filter} object. |
| * |
| * <p> |
| * Services which match the specified {@code Filter} object will be tracked |
| * by this {@code ServiceTracker}. |
| * |
| * @param context The {@code BundleContext} against which the tracking is |
| * done. |
| * @param filter The {@code Filter} 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}. If customizer |
| * is null, then this {@code ServiceTracker} will be used as the |
| * {@code ServiceTrackerCustomizer} and this {@code ServiceTracker} |
| * will call the {@code ServiceTrackerCustomizer} methods on itself. |
| * @param initialActive Initial active state of the tracker. |
| * @since 1.1 |
| */ |
| public ServiceTracker(final BundleContext context, final Filter filter, final ServiceTrackerCustomizer<S, T> customizer, boolean initialActive) { |
| this.context = context; |
| this.trackReference = null; |
| this.trackClass = null; |
| this.listenerFilter = filter.toString(); |
| this.filter = filter; |
| this.customizer = customizer; |
| this.active = initialActive; |
| if ((context == null)) { |
| /* |
| * we throw a NPE here to be consistent with the other constructors |
| */ |
| throw new NullPointerException( "BundleContext"); |
| } |
| } |
| |
| /** |
| * Create a {@code ServiceTracker} on the specified class. |
| * |
| * <p> |
| * Services registered under the name of the specified class will be tracked |
| * by this {@code ServiceTracker}. |
| * |
| * @param context The {@code BundleContext} against which the tracking is |
| * done. |
| * @param clazz The class of the services to be tracked. |
| * @param customizer The customizer object to call when services are added, |
| * modified, or removed in this {@code ServiceTracker}. If customizer |
| * is {@code null}, then this {@code ServiceTracker} will be used as |
| * the {@code ServiceTrackerCustomizer} and this |
| * {@code ServiceTracker} will call the |
| * {@code ServiceTrackerCustomizer} methods on itself. |
| * @since 1.5 |
| */ |
| public ServiceTracker(final BundleContext context, final Class<S> clazz, final ServiceTrackerCustomizer<S, T> customizer) { |
| this(context, clazz.getName(), customizer); |
| } |
| |
| /** |
| * Open this {@code ServiceTracker} and begin tracking services. |
| * |
| * <p> |
| * This implementation calls {@code open(false)}. |
| * |
| * @throws java.lang.IllegalStateException If the {@code BundleContext} with |
| * which this {@code ServiceTracker} was created is no longer valid. |
| * @see #open(boolean, java.util.concurrent.atomic.AtomicInteger) |
| * @param trackingCount |
| */ |
| public void open( AtomicInteger trackingCount ) { |
| open(false, trackingCount ); |
| } |
| |
| /** |
| * Open this {@code ServiceTracker} and begin tracking services. |
| * |
| * <p> |
| * Services which match the search criteria specified when this |
| * {@code ServiceTracker} was created are now tracked by this |
| * {@code ServiceTracker}. |
| * |
| * |
| * @param trackAllServices If {@code true}, then this {@code ServiceTracker} |
| * will track all matching services regardless of class loader |
| * accessibility. If {@code false}, then this {@code ServiceTracker} |
| * will only track matching services which are class loader |
| * accessible to the bundle whose {@code BundleContext} is used by |
| * this {@code ServiceTracker}. |
| * @param trackingCount |
| * @throws java.lang.IllegalStateException If the {@code BundleContext} with |
| * which this {@code ServiceTracker} was created is no longer valid. |
| * @since 1.3 |
| */ |
| public void open( boolean trackAllServices, AtomicInteger trackingCount ) { |
| final Tracked t; |
| synchronized (this) { |
| if (tracked != null) { |
| return; |
| } |
| if (DEBUG) { |
| System.out.println("ServiceTracker.open: " + filter); |
| } |
| t = trackAllServices ? new AllTracked( trackingCount ) : new Tracked( trackingCount ); |
| synchronized (t) { |
| try { |
| context.addServiceListener(t, listenerFilter); |
| ServiceReference<S>[] references = null; |
| if (trackClass != null) { |
| references = getInitialReferences(trackAllServices, trackClass, null); |
| } else { |
| if (trackReference != null) { |
| if (trackReference.getBundle() != null) { |
| ServiceReference<S>[] single = new ServiceReference[] {trackReference}; |
| references = single; |
| } |
| } else { /* user supplied filter */ |
| references = getInitialReferences(trackAllServices, null, listenerFilter); |
| } |
| } |
| /* set tracked with the initial references */ |
| t.setInitial(references); |
| } catch (InvalidSyntaxException e) { |
| throw new RuntimeException("unexpected InvalidSyntaxException: " + e.getMessage(), e); |
| } |
| } |
| tracked = t; |
| } |
| /* Call tracked outside of synchronized region */ |
| t.trackInitial(); /* process the initial references */ |
| } |
| |
| /** |
| * Returns the list of initial {@code ServiceReference}s that will be |
| * tracked by this {@code ServiceTracker}. |
| * |
| * @param trackAllServices If {@code true}, use |
| * {@code getAllServiceReferences}. |
| * @param className The class name with which the service was registered, or |
| * {@code null} for all services. |
| * @param filterString The filter criteria or {@code null} for all services. |
| * @return The list of initial {@code ServiceReference}s. |
| * @throws InvalidSyntaxException If the specified filterString has an |
| * invalid syntax. |
| */ |
| private ServiceReference<S>[] getInitialReferences(boolean trackAllServices, String className, String filterString) throws InvalidSyntaxException { |
| ServiceReference<S>[] result = (ServiceReference<S>[]) ((trackAllServices) ? context.getAllServiceReferences(className, filterString) : context.getServiceReferences(className, filterString)); |
| return result; |
| } |
| |
| /** |
| * Close this {@code ServiceTracker}. |
| * |
| * <p> |
| * This method should be called when this {@code ServiceTracker} should end |
| * the tracking of services. |
| * |
| * <p> |
| * This implementation calls {@link #getServiceReferences()} to get the list |
| * of tracked services to remove. |
| * @param trackingCount |
| */ |
| public SortedMap<ServiceReference<S>, T> close( AtomicInteger trackingCount ) { |
| final Tracked outgoing; |
| // final ServiceReference<S>[] references; |
| SortedMap<ServiceReference<S>, T> map = new TreeMap<ServiceReference<S>, T>(Collections.reverseOrder()); |
| synchronized (this) { |
| outgoing = tracked; |
| if (outgoing == null) { |
| return map; |
| } |
| if (DEBUG) { |
| System.out.println("ServiceTracker.close: " + filter); |
| } |
| outgoing.close(); |
| synchronized ( outgoing ) |
| { |
| trackingCount.set( outgoing.getTrackingCount() ); |
| outgoing.copyEntries( map ); |
| } |
| // 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); |
| // } |
| // } |
| if (DEBUG) { |
| if ((cachedReference == null) && (cachedService == null)) { |
| System.out.println("ServiceTracker.close[cached cleared]: " + filter); |
| } |
| } |
| return map; |
| } |
| |
| public void completeClose(Map<ServiceReference<S>, T> toUntrack) { |
| final Tracked outgoing; |
| synchronized (this) { |
| outgoing = tracked; |
| if (outgoing == null) { |
| return; |
| } |
| if (DEBUG) { |
| System.out.println("ServiceTracker.close: " + filter); |
| } |
| } |
| for (ServiceReference<S> ref: toUntrack.keySet()) { |
| outgoing.untrack( ref, null ); |
| } |
| tracked = null; |
| } |
| |
| /** |
| * Default implementation of the |
| * {@code ServiceTrackerCustomizer.addingService} method. |
| * |
| * <p> |
| * This method is only called when this {@code ServiceTracker} has been |
| * constructed with a {@code null ServiceTrackerCustomizer} argument. |
| * |
| * <p> |
| * This implementation returns the result of calling {@code getService} on |
| * the {@code BundleContext} with which this {@code ServiceTracker} was |
| * created passing the specified {@code ServiceReference}. |
| * <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, int) removedService} to unget |
| * the service. |
| * |
| * @param reference The reference to the service being added to this |
| * {@code ServiceTracker}. |
| * @return The service object to be tracked for the service added to this |
| * {@code ServiceTracker}. |
| * @see ServiceTrackerCustomizer#addingService(org.osgi.framework.ServiceReference |
| */ |
| public T addingService(ServiceReference<S> reference, int trackingCount) { |
| T result = (T) context.getService(reference); |
| return result; |
| } |
| |
| /** |
| * Default implementation of the |
| * {@code ServiceTrackerCustomizer.modifiedService} method. |
| * |
| * <p> |
| * This method is only called when this {@code ServiceTracker} has been |
| * constructed with a {@code null ServiceTrackerCustomizer} 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(org.osgi.framework.ServiceReference, Object, int) |
| */ |
| public void modifiedService(ServiceReference<S> reference, T service, int trackingCount) { |
| /* do nothing */ |
| } |
| |
| /** |
| * Default implementation of the |
| * {@code ServiceTrackerCustomizer.removedService} method. |
| * |
| * <p> |
| * This method is only called when this {@code ServiceTracker} has been |
| * constructed with a {@code null ServiceTrackerCustomizer} argument. |
| * |
| * <p> |
| * This implementation calls {@code ungetService}, on the |
| * {@code BundleContext} with which this {@code ServiceTracker} was created, |
| * passing the specified {@code ServiceReference}. |
| * <p> |
| * This method can be overridden in a subclass. If the default |
| * implementation of {@link #addingService(ServiceReference, int) 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(org.osgi.framework.ServiceReference, Object, int) |
| */ |
| public void removedService(ServiceReference<S> reference, T service, int trackingCount) { |
| context.ungetService(reference); |
| } |
| |
| /** |
| * Wait for at least one service to be tracked by this |
| * {@code ServiceTracker}. This method will also return when this |
| * {@code ServiceTracker} is closed. |
| * |
| * <p> |
| * It is strongly recommended that {@code waitForService} is not used during |
| * the calling of the {@code BundleActivator} methods. |
| * {@code BundleActivator} 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 T waitForService(long timeout) throws InterruptedException { |
| if (timeout < 0) { |
| throw new IllegalArgumentException("timeout value is negative"); |
| } |
| |
| T object = getService(); |
| if (object != null) { |
| return object; |
| } |
| |
| final long endTime = (timeout == 0) ? 0 : (System.currentTimeMillis() + timeout); |
| do { |
| 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 (endTime > 0) { // if we have a timeout |
| timeout = endTime - System.currentTimeMillis(); |
| if (timeout <= 0) { // that has expired |
| break; |
| } |
| } |
| } while (object == null); |
| return object; |
| } |
| |
| /** |
| * Return an array of {@code ServiceReference}s for all services being |
| * tracked by this {@code ServiceTracker}. |
| * |
| * @return Array of {@code ServiceReference}s or {@code null} if no services |
| * are being tracked. |
| */ |
| public ServiceReference<S>[] 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; |
| } |
| ServiceReference<S>[] result = new ServiceReference[length]; |
| return t.copyKeys(result); |
| } |
| } |
| |
| /** |
| * Returns a {@code ServiceReference} for one of the services being tracked |
| * by this {@code ServiceTracker}. |
| * |
| * <p> |
| * If multiple services are being tracked, the service with the highest |
| * ranking (as specified in its {@code service.ranking} property) is |
| * returned. If there is a tie in ranking, the service with the lowest |
| * service ID (as specified in its {@code service.id} property); that is, |
| * the service that was registered first is returned. This is the same |
| * algorithm used by {@code BundleContext.getServiceReference}. |
| * |
| * <p> |
| * This implementation calls {@link #getServiceReferences()} to get the list |
| * of references for the tracked services. |
| * |
| * @return A {@code ServiceReference} or {@code null} if no services are |
| * being tracked. |
| * @since 1.1 |
| */ |
| public ServiceReference<S> getServiceReference() { |
| ServiceReference<S> 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<S>[] 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} if |
| * the specified referenced service is being tracked by this |
| * {@code ServiceTracker}. |
| * |
| * @param reference The reference to the desired service. |
| * @return A service object or {@code null} if the service referenced by the |
| * specified {@code ServiceReference} is not being tracked. |
| */ |
| public T getService(ServiceReference<S> 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}. |
| * |
| * <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} 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<S>[] 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}. |
| * |
| * <p> |
| * If any services are being tracked, this implementation returns the result |
| * of calling {@code getService(getServiceReference())}. |
| * |
| * @return A service object or {@code null} if no services are being |
| * tracked. |
| */ |
| public T getService() { |
| T 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<S> reference = getServiceReference(); |
| if (reference == null) { |
| return null; |
| } |
| return cachedService = getService(reference); |
| } |
| |
| /** |
| * Remove a service from this {@code ServiceTracker}. |
| * |
| * The specified service will be removed from this {@code ServiceTracker}. |
| * If the specified service was being tracked then the |
| * {@code ServiceTrackerCustomizer.removedService} method will be called for |
| * that service. |
| * |
| * @param reference The reference to the service to be removed. |
| */ |
| public void remove(ServiceReference<S> reference) { |
| final Tracked t = tracked(); |
| if (t == null) { /* if ServiceTracker is not open */ |
| return; |
| } |
| t.untrack(reference, null); |
| } |
| |
| /** |
| * Return the number of services being tracked by this |
| * {@code ServiceTracker}. |
| * |
| * @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}. |
| * |
| * The tracking count is initialized to 0 when this {@code ServiceTracker} |
| * is opened. Every time a service is added, modified or removed from this |
| * {@code ServiceTracker}, the tracking count is incremented. |
| * |
| * <p> |
| * The tracking count can be used to determine if this |
| * {@code ServiceTracker} 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} since |
| * the previous tracking count was collected. |
| * |
| * @since 1.2 |
| * @return The tracking count for this {@code ServiceTracker} or -1 if this |
| * {@code ServiceTracker} 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); |
| } |
| } |
| |
| /** |
| * Return a {@code SortedMap} of the {@code ServiceReference}s and service |
| * objects for all services being tracked by this {@code ServiceTracker}. |
| * The map is sorted in reverse natural order of {@code ServiceReference}. |
| * That is, the first entry is the service with the highest ranking and the |
| * lowest service id. |
| * |
| * @return A {@code SortedMap} with the {@code ServiceReference}s and |
| * service objects for all services being tracked by this |
| * {@code ServiceTracker}. If no services are being tracked, then |
| * the returned map is empty. |
| * @since 1.5 |
| * @param activate |
| * @param trackingCount |
| */ |
| public SortedMap<ServiceReference<S>, T> getTracked( Boolean activate, AtomicInteger trackingCount ) { |
| SortedMap<ServiceReference<S>, T> map = new TreeMap<ServiceReference<S>, T>(Collections.reverseOrder()); |
| final Tracked t = tracked(); |
| if (t == null) { /* if ServiceTracker is not open */ |
| return map; |
| } |
| synchronized (t) { |
| if ( activate != null ) |
| { |
| active = activate; |
| } |
| trackingCount.set( t.getTrackingCount() ); |
| return t.copyEntries(map); |
| } |
| } |
| |
| void deactivate() { |
| final Tracked t = tracked(); |
| if (t == null) { /* if ServiceTracker is not open */ |
| return; |
| } |
| synchronized (t) { |
| active = false; |
| } |
| } |
| |
| /** |
| * Return if this {@code ServiceTracker} is empty. |
| * |
| * @return {@code true} if this {@code ServiceTracker} is not tracking any |
| * services. |
| * @since 1.5 |
| */ |
| public boolean isEmpty() { |
| final Tracked t = tracked(); |
| if (t == null) { /* if ServiceTracker is not open */ |
| return true; |
| } |
| synchronized (t) { |
| return t.isEmpty(); |
| } |
| } |
| |
| public boolean isActive() { |
| final Tracked t = tracked(); |
| if (t == null) { /* if ServiceTracker is not open */ |
| return false; |
| } |
| synchronized (t) { |
| return active; |
| } |
| |
| } |
| |
| /** |
| * Return an array of service objects for all services being tracked by this |
| * {@code ServiceTracker}. The runtime type of the returned array is that of |
| * the specified array. |
| * |
| * <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. |
| * |
| * @param array An array into which the tracked service objects will be |
| * stored, if the array is large enough. |
| * @return An array of service objects being tracked. If the specified array |
| * is large enough to hold the result, then the specified array is |
| * returned. If the specified array is longer then necessary to hold |
| * the result, the array element after the last service object is |
| * set to {@code null}. If the specified array is not large enough |
| * to hold the result, a new array is created and returned. |
| * @since 1.5 |
| */ |
| public T[] getServices(T[] array) { |
| final Tracked t = tracked(); |
| if (t == null) { /* if ServiceTracker is not open */ |
| if (array.length > 0) { |
| array[0] = null; |
| } |
| return array; |
| } |
| synchronized (t) { |
| ServiceReference<S>[] references = getServiceReferences(); |
| int length = (references == null) ? 0 : references.length; |
| if (length == 0) { |
| if (array.length > 0) { |
| array[0] = null; |
| } |
| return array; |
| } |
| if (length > array.length) { |
| array = (T[]) Array.newInstance(array.getClass().getComponentType(), length); |
| } |
| for (int i = 0; i < length; i++) { |
| array[i] = getService(references[i]); |
| } |
| if (array.length > length) { |
| array[length] = null; |
| } |
| return array; |
| } |
| } |
| |
| /** |
| * Abstract class to track items. If a Tracker is reused (closed then reopened), |
| * then a new AbstractTracked object is used. This class acts a map of tracked |
| * item -> customized object. Subclasses of this class will act as the listener |
| * object for the tracker. This class is used to synchronize access to the |
| * tracked items. This is not a public class. It is only for use by the |
| * implementation of the Tracker class. |
| * |
| * @param <S> The tracked item. It is the key. |
| * @param <T> The value mapped to the tracked item. |
| * @param <R> The reason the tracked item is being tracked or untracked. |
| * @ThreadSafe |
| * @version $Id: 16340086b98d308c2d12f13bcd87fc6467a5a367 $ |
| * @since 1.4 |
| */ |
| abstract class AbstractTracked<S, T, R> { |
| /* set this to true to compile in debug messages */ |
| static final boolean DEBUG = false; |
| |
| /** |
| * Map of tracked items to customized objects. |
| * |
| * @GuardedBy this |
| */ |
| private final Map<S, T> tracked; |
| |
| /** |
| * Modification count. This field is initialized to zero and incremented by |
| * modified. |
| * |
| * @GuardedBy this |
| */ |
| private final AtomicInteger trackingCount; |
| |
| /** |
| * List of items in the process of being added. This is used to deal with |
| * nesting of events. Since events may be synchronously delivered, events |
| * can be nested. For example, when processing the adding of a service and |
| * the customizer causes the service to be unregistered, notification to the |
| * nested call to untrack that the service was unregistered can be made to |
| * the track method. |
| * |
| * Since the ArrayList implementation is not synchronized, all access to |
| * this list must be protected by the same synchronized object for |
| * thread-safety. |
| * |
| * @GuardedBy this |
| */ |
| private final List<S> adding; |
| |
| /** |
| * true if the tracked object is closed. |
| * |
| * This field is volatile because it is set by one thread and read by |
| * another. |
| */ |
| volatile boolean closed; |
| |
| /** |
| * Initial list of items for the tracker. This is used to correctly process |
| * the initial items which could be modified before they are tracked. This |
| * is necessary since the initial set of tracked items are not "announced" |
| * by events and therefore the event which makes the item untracked could be |
| * delivered before we track the item. |
| * |
| * An item must not be in both the initial and adding lists at the same |
| * time. An item must be moved from the initial list to the adding list |
| * "atomically" before we begin tracking it. |
| * |
| * Since the LinkedList implementation is not synchronized, all access to |
| * this list must be protected by the same synchronized object for |
| * thread-safety. |
| * |
| * @GuardedBy this |
| */ |
| private final LinkedList<S> initial; |
| |
| /** |
| * AbstractTracked constructor. |
| * @param trackingCount |
| */ |
| AbstractTracked( AtomicInteger trackingCount ) { |
| tracked = new HashMap<S, T>(); |
| this.trackingCount = trackingCount; |
| adding = new ArrayList<S>(6); |
| initial = new LinkedList<S>(); |
| closed = false; |
| } |
| |
| /** |
| * Set initial list of items into tracker before events begin to be |
| * received. |
| * |
| * This method must be called from Tracker's open method while synchronized |
| * on this object in the same synchronized block as the add listener call. |
| * |
| * @param list The initial list of items to be tracked. {@code null} entries |
| * in the list are ignored. |
| * @GuardedBy this |
| */ |
| void setInitial(S[] list) { |
| if (list == null) { |
| return; |
| } |
| for (S item : list) { |
| if (item == null) { |
| continue; |
| } |
| if (DEBUG) { |
| System.out.println("AbstractTracked.setInitial: " + item); //$NON-NLS-1$ |
| } |
| initial.add(item); |
| } |
| } |
| |
| /** |
| * Track the initial list of items. This is called after events can begin to |
| * be received. |
| * |
| * This method must be called from Tracker's open method while not |
| * synchronized on this object after the add listener call. |
| * |
| */ |
| void trackInitial() { |
| while (true) { |
| S item; |
| synchronized (this) { |
| if (closed || (initial.size() == 0)) { |
| /* |
| * if there are no more initial items |
| */ |
| return; /* we are done */ |
| } |
| /* |
| * move the first item from the initial list to the adding list |
| * within this synchronized block. |
| */ |
| item = initial.removeFirst(); |
| if (tracked.get(item) != null) { |
| /* if we are already tracking this item */ |
| if (DEBUG) { |
| System.out.println("AbstractTracked.trackInitial[already tracked]: " + item); //$NON-NLS-1$ |
| } |
| continue; /* skip this item */ |
| } |
| if (adding.contains(item)) { |
| /* |
| * if this item is already in the process of being added. |
| */ |
| if (DEBUG) { |
| System.out.println("AbstractTracked.trackInitial[already adding]: " + item); //$NON-NLS-1$ |
| } |
| continue; /* skip this item */ |
| } |
| adding.add(item); |
| } |
| if (DEBUG) { |
| System.out.println("AbstractTracked.trackInitial: " + item); //$NON-NLS-1$ |
| } |
| trackAdding(item, null); /* |
| * Begin tracking it. We call trackAdding |
| * since we have already put the item in the |
| * adding list. |
| */ |
| } |
| } |
| |
| /** |
| * Called by the owning Tracker object when it is closed. |
| */ |
| void close() { |
| closed = true; |
| } |
| |
| /** |
| * Begin to track an item. |
| * |
| * @param item Item to be tracked. |
| * @param related Action related object. |
| */ |
| void track(final S item, final R related) { |
| boolean tracking; |
| final T object; |
| int trackingCount = -1; |
| synchronized (this) { |
| if (closed) { |
| return; |
| } |
| tracking = tracked.containsKey( item ); |
| object = tracked.get(item); |
| if (!tracking) { /* we are not tracking the item */ |
| if (adding.contains(item)) { |
| /* if this item is already in the process of being added. */ |
| if (DEBUG) { |
| System.out.println("AbstractTracked.track[already adding]: " + item); //$NON-NLS-1$ |
| } |
| return; |
| } |
| adding.add(item); /* mark this item is being added */ |
| } else { /* we are currently tracking this item */ |
| if (DEBUG) { |
| System.out.println("AbstractTracked.track[modified]: " + item); //$NON-NLS-1$ |
| } |
| trackingCount = modified(); /* increment modification count */ |
| } |
| } |
| |
| if (!tracking) { /* we are not tracking the item */ |
| trackAdding(item, related); |
| } else { |
| /* Call customizer outside of synchronized region */ |
| customizerModified(item, related, object, trackingCount ); |
| /* |
| * If the customizer throws an unchecked exception, it is safe to |
| * let it propagate |
| */ |
| } |
| } |
| |
| /** |
| * Common logic to add an item to the tracker used by track and |
| * trackInitial. The specified item must have been placed in the adding list |
| * before calling this method. |
| * |
| * @param item Item to be tracked. |
| * @param related Action related object. |
| */ |
| private void trackAdding(final S item, final R related) { |
| if (DEBUG) { |
| System.out.println("AbstractTracked.trackAdding: " + item); //$NON-NLS-1$ |
| } |
| T object = null; |
| boolean becameUntracked = false; |
| int trackingCount = -1; |
| /* Call customizer outside of synchronized region */ |
| try { |
| object = customizerAdding(item, related); |
| /* |
| * If the customizer throws an unchecked exception, it will |
| * propagate after the finally |
| */ |
| } finally { |
| synchronized (this) { |
| if (adding.remove(item) && !closed) { |
| /* |
| * if the item was not untracked during the customizer |
| * callback |
| */ |
| tracked.put( item, object ); |
| trackingCount = modified(); /* increment modification count */ |
| notifyAll(); /* notify any waiters */ |
| } else { |
| becameUntracked = true; |
| } |
| } |
| } |
| /* |
| * The item became untracked during the customizer callback. |
| */ |
| if (becameUntracked) { |
| if (DEBUG) { |
| System.out.println("AbstractTracked.trackAdding[removed]: " + item); //$NON-NLS-1$ |
| } |
| /* Call customizer outside of synchronized region */ |
| customizerRemoved(item, related, object, trackingCount ); |
| /* |
| * If the customizer throws an unchecked exception, it is safe to |
| * let it propagate |
| */ |
| } else { |
| customizerAdded( item, related, object, trackingCount ); |
| } |
| } |
| |
| /** |
| * Discontinue tracking the item. |
| * |
| * @param item Item to be untracked. |
| * @param related Action related object. |
| */ |
| void untrack(final S item, final R related) { |
| final T object; |
| int trackingCount; |
| synchronized (this) { |
| if (initial.remove(item)) { /* |
| * if this item is already in the list |
| * of initial references to process |
| */ |
| if (DEBUG) { |
| System.out.println("AbstractTracked.untrack[removed from initial]: " + item); //$NON-NLS-1$ |
| } |
| return; /* |
| * we have removed it from the list and it will not be |
| * processed |
| */ |
| } |
| |
| if (adding.remove(item)) { /* |
| * if the item is in the process of |
| * being added |
| */ |
| if (DEBUG) { |
| System.out.println("AbstractTracked.untrack[being added]: " + item); //$NON-NLS-1$ |
| } |
| return; /* |
| * in case the item is untracked while in the process of |
| * adding |
| */ |
| } |
| object = tracked.remove(item); /* * must remove from tracker before |
| * calling customizer callback |
| */ |
| if (object == null) { /* are we actually tracking the item */ |
| return; |
| } |
| trackingCount = modified(); /* increment modification count */ |
| } |
| if (DEBUG) { |
| System.out.println("AbstractTracked.untrack[removed]: " + item); //$NON-NLS-1$ |
| } |
| /* Call customizer outside of synchronized region */ |
| customizerRemoved(item, related, object, trackingCount ); |
| /* |
| * If the customizer throws an unchecked exception, it is safe to let it |
| * propagate |
| */ |
| } |
| |
| /** |
| * Returns the number of tracked items. |
| * |
| * @return The number of tracked items. |
| * |
| * @GuardedBy this |
| */ |
| int size() { |
| return tracked.size(); |
| } |
| |
| /** |
| * Returns if the tracker is empty. |
| * |
| * @return Whether the tracker is empty. |
| * |
| * @GuardedBy this |
| * @since 1.5 |
| */ |
| boolean isEmpty() { |
| return tracked.isEmpty(); |
| } |
| |
| /** |
| * Return the customized object for the specified item |
| * |
| * @param item The item to lookup in the map |
| * @return The customized object for the specified item. |
| * |
| * @GuardedBy this |
| */ |
| T getCustomizedObject(final S item) { |
| return tracked.get( item ); |
| } |
| |
| /** |
| * Copy the tracked items into an array. |
| * |
| * @param list An array to contain the tracked items. |
| * @return The specified list if it is large enough to hold the tracked |
| * items or a new array large enough to hold the tracked items. |
| * @GuardedBy this |
| */ |
| S[] copyKeys(final S[] list) { |
| return tracked.keySet().toArray(list); |
| } |
| |
| /** |
| * Increment the modification count. If this method is overridden, the |
| * overriding method MUST call this method to increment the tracking count. |
| * |
| * @GuardedBy this |
| */ |
| int modified() { |
| return trackingCount.incrementAndGet(); |
| } |
| |
| /** |
| * Returns the tracking count for this {@code ServiceTracker} object. |
| * |
| * The tracking count is initialized to 0 when this object is opened. Every |
| * time an item is added, modified or removed from this object the tracking |
| * count is incremented. |
| * |
| * @GuardedBy this |
| * @return The tracking count for this object. |
| */ |
| int getTrackingCount() { |
| return trackingCount.get(); |
| } |
| |
| /** |
| * Copy the tracked items and associated values into the specified map. |
| * |
| * @param <M> Type of {@code Map} to hold the tracked items and associated |
| * values. |
| * @param map The map into which to copy the tracked items and associated |
| * values. This map must not be a user provided map so that user code |
| * is not executed while synchronized on this. |
| * @return The specified map. |
| * @GuardedBy this |
| * @since 1.5 |
| */ |
| <M extends Map<? super S, ? super T>> M copyEntries(final M map) { |
| map.putAll(tracked); |
| return map; |
| } |
| |
| /** |
| * 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} if the |
| * item is not to be tracked. |
| */ |
| abstract T customizerAdding( final S item, final R related ); |
| |
| abstract void customizerAdded( final S item, final R related, final T object, int trackingCount ); |
| |
| /** |
| * 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. |
| * @param trackingCount |
| */ |
| abstract void customizerModified( final S item, final R related, final T object, int trackingCount ); |
| |
| /** |
| * 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. |
| * @param trackingCount |
| */ |
| abstract void customizerRemoved( final S item, final R related, final T object, int trackingCount ); |
| } |
| |
| |
| /** |
| * Inner class which subclasses AbstractTracked. This class is the |
| * {@code ServiceListener} object for the tracker. |
| * |
| * @ThreadSafe |
| */ |
| private class Tracked extends AbstractTracked<ServiceReference<S>, T, ServiceEvent> implements ServiceListener { |
| /** |
| * Tracked constructor. |
| * @param trackingCount |
| */ |
| Tracked( AtomicInteger trackingCount ) { |
| super( trackingCount ); |
| } |
| |
| /** |
| * {@code ServiceListener} method for the {@code ServiceTracker} class. |
| * This method must NOT be synchronized to avoid deadlock potential. |
| * |
| * @param event {@code ServiceEvent} object from the framework. |
| */ |
| final public void serviceChanged(final ServiceEvent event) { |
| /* |
| * Check if we had a delayed call (which could happen when we |
| * close). |
| */ |
| if (closed) { |
| return; |
| } |
| final ServiceReference<S> reference = (ServiceReference<S>) event.getServiceReference(); |
| if (DEBUG) { |
| System.out.println("ServiceTracker.Tracked.serviceChanged[" + event.getType() + "]: " + reference); |
| } |
| |
| switch (event.getType()) { |
| case ServiceEvent.REGISTERED : |
| case ServiceEvent.MODIFIED : |
| track(reference, event); |
| /* |
| * If the customizer throws an unchecked exception, it is |
| * safe to let it propagate |
| */ |
| break; |
| case ServiceEvent.MODIFIED_ENDMATCH : |
| case ServiceEvent.UNREGISTERING : |
| untrack(reference, event); |
| /* |
| * If the customizer throws an unchecked exception, it is |
| * safe to let it propagate |
| */ |
| break; |
| default : |
| System.out.println("Unrecognized event type: ServiceTracker.Tracked.serviceChanged[" + event.getType() + "]: " + reference); |
| |
| } |
| } |
| |
| /** |
| * Increment the tracking count and tell the tracker there was a |
| * modification. |
| * |
| * @GuardedBy this |
| */ |
| final int modified() { |
| int trackingCount = super.modified(); /* increment the modification count */ |
| ServiceTracker.this.modified(); |
| return trackingCount; |
| } |
| |
| /** |
| * 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} if the |
| * item is not to be tracked. |
| */ |
| final T customizerAdding( final ServiceReference<S> item, final ServiceEvent related ) { |
| return customizer.addingService( item ); |
| } |
| |
| final void customizerAdded( final ServiceReference<S> item, final ServiceEvent related, final T object, int trackingCount ) { |
| customizer.addedService( item, object, trackingCount ); |
| } |
| |
| /** |
| * 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. |
| * @param trackingCount |
| */ |
| final void customizerModified( final ServiceReference<S> item, final ServiceEvent related, final T object, int trackingCount ) { |
| customizer.modifiedService( item, object, trackingCount ); |
| } |
| |
| /** |
| * 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. |
| * @param trackingCount |
| */ |
| final void customizerRemoved( final ServiceReference<S> item, final ServiceEvent related, final T object, int trackingCount ) { |
| customizer.removedService(item, object, trackingCount ); |
| } |
| } |
| |
| /** |
| * 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 |
| */ |
| private class AllTracked extends Tracked implements AllServiceListener { |
| /** |
| * AllTracked constructor. |
| * @param trackingCount |
| */ |
| AllTracked( AtomicInteger trackingCount ) { |
| super( trackingCount ); |
| } |
| } |
| } |
