| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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. |
| */ |
| |
| /* |
| * Copyright (c) OSGi Alliance (2007, 2008). 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.camel.impl.osgi.tracker; |
| |
| import org.osgi.framework.Bundle; |
| import org.osgi.framework.BundleContext; |
| import org.osgi.framework.BundleEvent; |
| import org.osgi.framework.SynchronousBundleListener; |
| |
| /** |
| * The <code>BundleTracker</code> class simplifies tracking bundles much like |
| * the <code>ServiceTracker</code> simplifies tracking services. |
| * <p> |
| * A <code>BundleTracker</code> is constructed with state criteria and a |
| * <code>BundleTrackerCustomizer</code> object. A <code>BundleTracker</code> can |
| * use the <code>BundleTrackerCustomizer</code> to select which bundles are |
| * tracked and to create a customized object to be tracked with the bundle. The |
| * <code>BundleTracker</code> can then be opened to begin tracking all bundles |
| * whose state matches the specified state criteria. |
| * <p> |
| * The <code>getBundles</code> method can be called to get the |
| * <code>Bundle</code> objects of the bundles being tracked. The |
| * <code>getObject</code> method can be called to get the customized object for |
| * a tracked bundle. |
| * <p> |
| * The <code>BundleTracker</code> class is thread-safe. It does not call a |
| * <code>BundleTrackerCustomizer</code> while holding any locks. |
| * <code>BundleTrackerCustomizer</code> implementations must also be |
| * thread-safe. |
| * |
| * @ThreadSafe |
| * @version |
| * @since 1.4 |
| */ |
| public class BundleTracker implements BundleTrackerCustomizer { |
| /* set this to true to compile in debug messages */ |
| static final boolean DEBUG = false; |
| |
| /** |
| * The Bundle Context used by this <code>BundleTracker</code>. |
| */ |
| protected final BundleContext context; |
| |
| /** |
| * State mask for bundles being tracked. This field contains the ORed values |
| * of the bundle states being tracked. |
| */ |
| final int mask; |
| |
| /** |
| * The <code>BundleTrackerCustomizer</code> object for this tracker. |
| */ |
| final BundleTrackerCustomizer customizer; |
| |
| /** |
| * Tracked bundles: <code>Bundle</code> object -> customized Object and |
| * <code>BundleListener</code> object |
| */ |
| private volatile Tracked tracked; |
| |
| /** |
| * Create a <code>BundleTracker</code> for bundles whose state is present in |
| * the specified state mask. |
| * <p> |
| * Bundles whose state is present on the specified state mask will be |
| * tracked by this <code>BundleTracker</code>. |
| * |
| * @param context The <code>BundleContext</code> against which the tracking |
| * is done. |
| * @param stateMask The bit mask of the <code>OR</code>ing of the bundle |
| * states to be tracked. |
| * @param customizer The customizer object to call when bundles are added, |
| * modified, or removed in this <code>BundleTracker</code>. If |
| * customizer is <code>null</code>, then this |
| * <code>BundleTracker</code> will be used as the |
| * <code>BundleTrackerCustomizer</code> and this |
| * <code>BundleTracker</code> will call the |
| * <code>BundleTrackerCustomizer</code> methods on itself. |
| * @see Bundle#getState() |
| */ |
| public BundleTracker(BundleContext context, int stateMask, BundleTrackerCustomizer customizer) { |
| this.context = context; |
| this.mask = stateMask; |
| this.customizer = (customizer == null) ? this : customizer; |
| } |
| |
| /** |
| * 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; |
| } |
| |
| |
| /** |
| * Open this <code>BundleTracker</code> and begin tracking bundles. |
| * <p> |
| * Bundle which match the state criteria specified when this |
| * <code>BundleTracker</code> was created are now tracked by this |
| * <code>BundleTracker</code>. |
| * |
| * @throws java.lang.IllegalStateException If the <code>BundleContext</code> |
| * with which this <code>BundleTracker</code> was created is no |
| * longer valid. |
| * @throws java.lang.SecurityException If the caller and this class do not |
| * have the appropriate |
| * <code>AdminPermission[context bundle,LISTENER]</code>, and |
| * the Java Runtime Environment supports permissions. |
| */ |
| public void open() { |
| final Tracked t; |
| synchronized (this) { |
| if (tracked != null) { |
| return; |
| } |
| if (DEBUG) { |
| System.out.println("BundleTracker.open"); //$NON-NLS-1$ |
| } |
| t = new Tracked(); |
| synchronized (t) { |
| context.addBundleListener(t); |
| Bundle[] bundles = context.getBundles(); |
| if (bundles != null) { |
| int length = bundles.length; |
| for (int i = 0; i < length; i++) { |
| int state = bundles[i].getState(); |
| if ((state & mask) == 0) { |
| /* null out bundles whose states are not interesting */ |
| bundles[i] = null; |
| } |
| } |
| /* set tracked with the initial bundles */ |
| t.setInitial(bundles); |
| } |
| } |
| tracked = t; |
| } |
| /* Call tracked outside of synchronized region */ |
| t.trackInitial(); /* process the initial references */ |
| } |
| |
| /** |
| * Close this <code>BundleTracker</code>. |
| * <p> |
| * This method should be called when this <code>BundleTracker</code> should |
| * end the tracking of bundles. |
| * <p> |
| * This implementation calls {@link #getBundles()} to get the list of |
| * tracked bundles to remove. |
| */ |
| public void close() { |
| final Bundle[] bundles; |
| final Tracked outgoing; |
| synchronized (this) { |
| outgoing = tracked; |
| if (outgoing == null) { |
| return; |
| } |
| if (DEBUG) { |
| System.out.println("BundleTracker.close"); //$NON-NLS-1$ |
| } |
| outgoing.close(); |
| bundles = getBundles(); |
| tracked = null; |
| try { |
| context.removeBundleListener(outgoing); |
| } catch (IllegalStateException e) { |
| /* In case the context was stopped. */ |
| } |
| } |
| if (bundles != null) { |
| for (int i = 0; i < bundles.length; i++) { |
| outgoing.untrack(bundles[i], null); |
| } |
| } |
| } |
| |
| /** |
| * Default implementation of the |
| * <code>BundleTrackerCustomizer.addingBundle</code> method. |
| * <p> |
| * This method is only called when this <code>BundleTracker</code> has been |
| * constructed with a <code>null BundleTrackerCustomizer</code> argument. |
| * <p> |
| * This implementation simply returns the specified <code>Bundle</code>. |
| * <p> |
| * This method can be overridden in a subclass to customize the object to be |
| * tracked for the bundle being added. |
| * |
| * @param bundle The <code>Bundle</code> being added to this |
| * <code>BundleTracker</code> object. |
| * @param event The bundle event which caused this customizer method to be |
| * called or <code>null</code> if there is no bundle event |
| * associated with the call to this method. |
| * @return The specified bundle. |
| * @see BundleTrackerCustomizer#addingBundle(Bundle, BundleEvent) |
| */ |
| public Object addingBundle(Bundle bundle, BundleEvent event) { |
| return bundle; |
| } |
| |
| /** |
| * Default implementation of the |
| * <code>BundleTrackerCustomizer.modifiedBundle</code> method. |
| * <p> |
| * This method is only called when this <code>BundleTracker</code> has been |
| * constructed with a <code>null BundleTrackerCustomizer</code> argument. |
| * <p> |
| * This implementation does nothing. |
| * |
| * @param bundle The <code>Bundle</code> whose state has been modified. |
| * @param event The bundle event which caused this customizer method to be |
| * called or <code>null</code> if there is no bundle event |
| * associated with the call to this method. |
| * @param object The customized object for the specified Bundle. |
| * @see BundleTrackerCustomizer#modifiedBundle(Bundle, BundleEvent, Object) |
| */ |
| public void modifiedBundle(Bundle bundle, BundleEvent event, Object object) { |
| /* do nothing */ |
| } |
| |
| /** |
| * Default implementation of the |
| * <code>BundleTrackerCustomizer.removedBundle</code> method. |
| * <p> |
| * This method is only called when this <code>BundleTracker</code> has been |
| * constructed with a <code>null BundleTrackerCustomizer</code> argument. |
| * <p> |
| * This implementation does nothing. |
| * |
| * @param bundle The <code>Bundle</code> being removed. |
| * @param event The bundle event which caused this customizer method to be |
| * called or <code>null</code> if there is no bundle event |
| * associated with the call to this method. |
| * @param object The customized object for the specified bundle. |
| * @see BundleTrackerCustomizer#removedBundle(Bundle, BundleEvent, Object) |
| */ |
| public void removedBundle(Bundle bundle, BundleEvent event, Object object) { |
| /* do nothing */ |
| } |
| |
| /** |
| * Return an array of <code>Bundle</code>s for all bundles being tracked by |
| * this <code>BundleTracker</code>. |
| * |
| * @return An array of <code>Bundle</code>s or <code>null</code> if no |
| * bundles are being tracked. |
| */ |
| public Bundle[] getBundles() { |
| final Tracked t = tracked(); |
| if (t == null) { /* if BundleTracker is not open */ |
| return null; |
| } |
| synchronized (t) { |
| int length = t.size(); |
| if (length == 0) { |
| return null; |
| } |
| return (Bundle[])t.getTracked(new Bundle[length]); |
| } |
| } |
| |
| /** |
| * Returns the customized object for the specified <code>Bundle</code> if |
| * the specified bundle is being tracked by this <code>BundleTracker</code>. |
| * |
| * @param bundle The <code>Bundle</code> being tracked. |
| * @return The customized object for the specified <code>Bundle</code> or |
| * <code>null</code> if the specified <code>Bundle</code> is not |
| * being tracked. |
| */ |
| public Object getObject(Bundle bundle) { |
| final Tracked t = tracked(); |
| if (t == null) { /* if BundleTracker is not open */ |
| return null; |
| } |
| synchronized (t) { |
| return t.getCustomizedObject(bundle); |
| } |
| } |
| |
| /** |
| * Remove a bundle from this <code>BundleTracker</code>. The specified |
| * bundle will be removed from this <code>BundleTracker</code> . If the |
| * specified bundle was being tracked then the |
| * <code>BundleTrackerCustomizer.removedBundle</code> method will be called |
| * for that bundle. |
| * |
| * @param bundle The <code>Bundle</code> to be removed. |
| */ |
| public void remove(Bundle bundle) { |
| final Tracked t = tracked(); |
| if (t == null) { /* if BundleTracker is not open */ |
| return; |
| } |
| t.untrack(bundle, null); |
| } |
| |
| /** |
| * Return the number of bundles being tracked by this |
| * <code>BundleTracker</code>. |
| * |
| * @return The number of bundles being tracked. |
| */ |
| public int size() { |
| final Tracked t = tracked(); |
| if (t == null) { /* if BundleTracker is not open */ |
| return 0; |
| } |
| synchronized (t) { |
| return t.size(); |
| } |
| } |
| |
| /** |
| * Returns the tracking count for this <code>BundleTracker</code>. The |
| * tracking count is initialized to 0 when this <code>BundleTracker</code> |
| * is opened. Every time a bundle is added, modified or removed from this |
| * <code>BundleTracker</code> the tracking count is incremented. |
| * <p> |
| * The tracking count can be used to determine if this |
| * <code>BundleTracker</code> has added, modified or removed a bundle by |
| * comparing a tracking count value previously collected with the current |
| * tracking count value. If the value has not changed, then no bundle has |
| * been added, modified or removed from this <code>BundleTracker</code> |
| * since the previous tracking count was collected. |
| * |
| * @return The tracking count for this <code>BundleTracker</code> or -1 if |
| * this <code>BundleTracker</code> is not open. |
| */ |
| public int getTrackingCount() { |
| final Tracked t = tracked(); |
| if (t == null) { /* if BundleTracker is not open */ |
| return -1; |
| } |
| synchronized (t) { |
| return t.getTrackingCount(); |
| } |
| } |
| |
| /** |
| * Inner class which subclasses AbstractTracked. This class is the |
| * <code>SynchronousBundleListener</code> object for the tracker. |
| * |
| * @ThreadSafe |
| * @since 1.4 |
| */ |
| class Tracked extends AbstractTracked implements SynchronousBundleListener { |
| /** |
| * Tracked constructor. |
| */ |
| Tracked() { |
| super(); |
| } |
| |
| /** |
| * <code>BundleListener</code> method for the <code>BundleTracker</code> |
| * class. This method must NOT be synchronized to avoid deadlock |
| * potential. |
| * |
| * @param event <code>BundleEvent</code> object from the framework. |
| */ |
| public void bundleChanged(final BundleEvent event) { |
| /* |
| * Check if we had a delayed call (which could happen when we |
| * close). |
| */ |
| if (closed) { |
| return; |
| } |
| final Bundle bundle = event.getBundle(); |
| final int state = bundle.getState(); |
| if (DEBUG) { |
| System.out.println("BundleTracker.Tracked.bundleChanged[" + state + "]: " + bundle); //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| |
| if ((state & mask) != 0) { |
| track(bundle, event); |
| /* |
| * If the customizer throws an unchecked exception, it is safe |
| * to let it propagate |
| */ |
| } else { |
| untrack(bundle, event); |
| /* |
| * If the customizer throws an unchecked exception, it is safe |
| * to let it propagate |
| */ |
| } |
| } |
| |
| /** |
| * 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.addingBundle((Bundle)item, (BundleEvent)related); |
| } |
| |
| /** |
| * 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.modifiedBundle((Bundle)item, (BundleEvent)related, 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.removedBundle((Bundle)item, (BundleEvent)related, object); |
| } |
| } |
| } |
