Author: gnodet
Date: Wed Sep 23 18:07:38 2009
New Revision: 818182
URL: http://svn.apache.org/viewvc?rev=818182&view=rev
Log:
The current activator use excessive synchronization which leads to deadlocks in
osgi
Added:
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/AbstractTracked.java
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTracker.java
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTrackerCustomizer.java
Modified:
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/Activator.java
Modified:
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/Activator.java
URL:
http://svn.apache.org/viewvc/camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/Activator.java?rev=818182&r1=818181&r2=818182&view=diff
==============================================================================
---
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/Activator.java
(original)
+++
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/Activator.java
Wed Sep 23 18:07:38 2009
@@ -23,15 +23,17 @@
import java.net.URL;
import java.util.Collection;
import java.util.Enumeration;
-import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.StringTokenizer;
+import java.util.concurrent.ConcurrentHashMap;
import org.apache.camel.Component;
import org.apache.camel.TypeConverter;
+import org.apache.camel.osgi.tracker.BundleTracker;
+import org.apache.camel.osgi.tracker.BundleTrackerCustomizer;
import org.apache.camel.spi.Language;
import org.apache.camel.spi.LanguageResolver;
import org.apache.camel.util.ObjectHelper;
@@ -44,19 +46,21 @@
import org.osgi.framework.SynchronousBundleListener;
import org.springframework.osgi.util.BundleDelegatingClassLoader;
-public class Activator implements BundleActivator, SynchronousBundleListener {
+public class Activator implements BundleActivator, BundleTrackerCustomizer {
public static final String META_INF_TYPE_CONVERTER =
"META-INF/services/org/apache/camel/TypeConverter";
public static final String META_INF_COMPONENT =
"META-INF/services/org/apache/camel/component/";
public static final String META_INF_LANGUAGE =
"META-INF/services/org/apache/camel/language/";
public static final String META_INF_LANGUAGE_RESOLVER =
"META-INF/services/org/apache/camel/language/resolver/";
private static final transient Log LOG =
LogFactory.getLog(Activator.class);
- private static final Map<String, ComponentEntry> COMPONENTS = new
HashMap<String, ComponentEntry>();
- private static final Map<URL, TypeConverterEntry> TYPE_CONVERTERS = new
HashMap<URL, TypeConverterEntry>();
- private static final Map<String, ComponentEntry> LANGUAGES = new
HashMap<String, ComponentEntry>();
- private static final Map<String, ComponentEntry> LANGUAGE_RESOLVERS = new
HashMap<String, ComponentEntry>();
+ private static final Map<String, ComponentEntry> COMPONENTS = new
ConcurrentHashMap<String, ComponentEntry>();
+ private static final Map<URL, TypeConverterEntry> TYPE_CONVERTERS = new
ConcurrentHashMap<URL, TypeConverterEntry>();
+ private static final Map<String, ComponentEntry> LANGUAGES = new
ConcurrentHashMap<String, ComponentEntry>();
+ private static final Map<String, ComponentEntry> LANGUAGE_RESOLVERS = new
ConcurrentHashMap<String, ComponentEntry>();
private static Bundle bundle;
+ private BundleTracker tracker;
+
private class ComponentEntry {
Bundle bundle;
String path;
@@ -70,32 +74,28 @@
Set<String> converterPackages;
}
- public void bundleChanged(BundleEvent event) {
- if (LOG.isTraceEnabled()) {
- LOG.trace("Bundle changed: " + event);
+ public Object addingBundle(Bundle bundle, BundleEvent event) {
+ modifiedBundle(bundle, event, null);
+ return bundle;
+ }
+
+ public void modifiedBundle(Bundle bundle, BundleEvent event, Object
object) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Bundle started: " + bundle.getSymbolicName());
}
+ mayBeAddComponentAndLanguageFor(bundle);
+ mayBeAddTypeConverterFor(bundle);
+ }
- try {
- Bundle bundle = event.getBundle();
- if (event.getType() == BundleEvent.RESOLVED) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Bundle resolved: " + bundle.getSymbolicName());
- }
- mayBeAddComponentAndLanguageFor(bundle);
- mayBeAddTypeConverterFor(bundle);
- } else if (event.getType() == BundleEvent.UNRESOLVED) {
- if (LOG.isDebugEnabled()) {
- LOG.debug("Bundle unresolved: " +
bundle.getSymbolicName());
- }
- mayBeRemoveComponentAndLanguageFor(bundle);
- mayBeRemoveTypeConverterFor(bundle);
- }
- } catch (Throwable e) {
- LOG.fatal("Exception occured during bundleChanged for event: " +
event, e);
+ public void removedBundle(Bundle bundle, BundleEvent event, Object
object) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Bundle stopped: " + bundle.getSymbolicName());
}
- }
+ mayBeRemoveComponentAndLanguageFor(bundle);
+ mayBeRemoveTypeConverterFor(bundle);
+ }
- protected synchronized void addComponentEntry(String entryPath, Bundle
bundle, Map<String, ComponentEntry> entries, Class clazz) {
+ protected void addComponentEntry(String entryPath, Bundle bundle,
Map<String, ComponentEntry> entries, Class clazz) {
// Check bundle compatibility
try {
if (bundle.loadClass(clazz.getName()) != clazz) {
@@ -127,7 +127,7 @@
addComponentEntry(META_INF_LANGUAGE_RESOLVER, bundle,
LANGUAGE_RESOLVERS, LanguageResolver.class);
}
- protected synchronized void mayBeAddTypeConverterFor(Bundle bundle) {
+ protected void mayBeAddTypeConverterFor(Bundle bundle) {
// Check bundle compatibility
try {
Class clazz = TypeConverter.class;
@@ -175,7 +175,7 @@
}
}
- protected synchronized void mayBeRemoveTypeConverterFor(Bundle bundle) {
+ protected void mayBeRemoveTypeConverterFor(Bundle bundle) {
TypeConverterEntry[] entriesArray =
TYPE_CONVERTERS.values().toArray(new TypeConverterEntry[0]);
for (TypeConverterEntry entry : entriesArray) {
if (entry.bundle == bundle) {
@@ -194,19 +194,9 @@
if (LOG.isDebugEnabled()) {
LOG.debug("Using bundle: " + bundle);
}
- context.addBundleListener(this);
-
- if (LOG.isDebugEnabled()) {
- LOG.debug("Checking existing bundles for Camel components,
languages and type converters");
- }
- for (Bundle bundle : context.getBundles()) {
- if (bundle.getState() == Bundle.RESOLVED || bundle.getState() ==
Bundle.STARTING
- || bundle.getState() == Bundle.ACTIVE || bundle.getState() ==
Bundle.STOPPING) {
- mayBeAddComponentAndLanguageFor(bundle);
- mayBeAddTypeConverterFor(bundle);
- }
- }
+ tracker = new BundleTracker(context, Bundle.ACTIVE, this);
+ tracker.open();
LOG.info("Camel activator started");
}
@@ -216,14 +206,7 @@
if (LOG.isDebugEnabled()) {
LOG.debug("Removing Camel bundles");
}
- for (Bundle bundle : context.getBundles()) {
- if (bundle.getState() == Bundle.RESOLVED || bundle.getState() ==
Bundle.STARTING
- || bundle.getState() == Bundle.ACTIVE || bundle.getState() ==
Bundle.STOPPING) {
- mayBeRemoveComponentAndLanguageFor(bundle);
- mayBeRemoveTypeConverterFor(bundle);
- }
- }
-
+ tracker.close();
LOG.info("Camel activator stopped");
}
@@ -269,27 +252,27 @@
return bundle;
}
- protected static synchronized TypeConverterEntry[]
getTypeConverterEntries() {
+ protected static TypeConverterEntry[] getTypeConverterEntries() {
Collection<TypeConverterEntry> entries = TYPE_CONVERTERS.values();
return entries.toArray(new TypeConverterEntry[entries.size()]);
}
- public static synchronized Class getComponent(String name) throws
Exception {
+ public static Class getComponent(String name) throws Exception {
LOG.trace("Finding Component: " + name);
return getClassFromEntries(name, COMPONENTS);
}
- public static synchronized Class getLanguage(String name) throws Exception
{
+ public static Class getLanguage(String name) throws Exception {
LOG.trace("Finding Language: " + name);
return getClassFromEntries(name, LANGUAGES);
}
- public static synchronized Class getLanguageResolver(String name) throws
Exception {
+ public static Class getLanguageResolver(String name) throws Exception {
LOG.trace("Finding LanguageResolver: " + name);
return getClassFromEntries(name, LANGUAGE_RESOLVERS);
}
- protected static synchronized Class getClassFromEntries(String name,
Map<String, ComponentEntry> entries) throws Exception {
+ protected static Class getClassFromEntries(String name, Map<String,
ComponentEntry> entries) throws Exception {
ComponentEntry entry = entries.get(name);
if (entry == null) {
return null;
Added:
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/AbstractTracked.java
URL:
http://svn.apache.org/viewvc/camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/AbstractTracked.java?rev=818182&view=auto
==============================================================================
---
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/AbstractTracked.java
(added)
+++
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/AbstractTracked.java
Wed Sep 23 18:07:38 2009
@@ -0,0 +1,449 @@
+/*
+ * 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.osgi.tracker;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * 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.
+ *
+ * @ThreadSafe
+ * @version $Revision$
+ * @since 1.4
+ */
+abstract class AbstractTracked {
+ /* 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 tracked;
+
+ /**
+ * Modification count. This field is initialized to zero and
incremented by
+ * modified.
+ *
+ * @GuardedBy this
+ */
+ private int 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 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 initial;
+
+ /**
+ * AbstractTracked constructor.
+ */
+ AbstractTracked() {
+ tracked = new HashMap();
+ trackingCount = 0;
+ adding = new ArrayList(6);
+ initial = new LinkedList();
+ 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</code>
+ * entries in the list are ignored.
+ * @GuardedBy this
+ */
+ void setInitial(Object[] list) {
+ if (list == null) {
+ return;
+ }
+ int size = list.length;
+ for (int i = 0; i < size; i++) {
+ Object item = list[i];
+ 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) {
+ Object 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 Object item, final Object related) {
+ final Object object;
+ synchronized (this) {
+ if (closed) {
+ return;
+ }
+ object = tracked.get(item);
+ if (object == null) { /* 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); //$NON-NLS-1$
+ }
+ modified(); /* increment modification count */
+ }
+ }
+
+ if (object == null) { /* we are not tracking the item */
+ trackAdding(item, related);
+ }
+ else {
+ /* Call customizer outside of synchronized region */
+ customizerModified(item, related, object);
+ /*
+ * 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 Object item, final Object related) {
+ if (DEBUG) {
+ System.out.println("AbstractTracked.trackAdding: " +
item); //$NON-NLS-1$
+ }
+ Object object = null;
+ boolean becameUntracked = false;
+ /* 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
+ */
+ if (object != null) {
+ tracked.put(item, object);
+ modified(); /* increment
modification count */
+ notifyAll(); /* notify any
waiters */
+ }
+ }
+ else {
+ becameUntracked = true;
+ }
+ }
+ }
+ /*
+ * The item became untracked during the customizer callback.
+ */
+ if (becameUntracked && (object != null)) {
+ if (DEBUG) {
+ System.out
+
.println("AbstractTracked.trackAdding[removed]: " + item); //$NON-NLS-1$
+ }
+ /* Call customizer outside of synchronized region */
+ customizerRemoved(item, related, object);
+ /*
+ * If the customizer throws an unchecked exception, it
is safe to
+ * let it propagate
+ */
+ }
+ }
+
+ /**
+ * Discontinue tracking the item.
+ *
+ * @param item Item to be untracked.
+ * @param related Action related object.
+ */
+ void untrack(final Object item, final Object related) {
+ final Object object;
+ 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;
+ }
+ 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);
+ /*
+ * 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();
+ }
+
+ /**
+ * 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
+ */
+ Object getCustomizedObject(final Object item) {
+ return tracked.get(item);
+ }
+
+ /**
+ * Return the list of tracked items.
+ *
+ * @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
+ */
+ Object[] getTracked(final Object[] 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
+ */
+ void modified() {
+ trackingCount++;
+ }
+
+ /**
+ * Returns the tracking count for this <code>ServiceTracker</code>
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;
+ }
+
+ /**
+ * 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.
+ */
+ abstract Object customizerAdding(final Object item, final Object
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.
+ */
+ abstract void customizerModified(final Object item, final Object
related,
+ final Object 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.
+ */
+ abstract void customizerRemoved(final Object item, final Object related,
+ final Object object);
+}
Added:
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTracker.java
URL:
http://svn.apache.org/viewvc/camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTracker.java?rev=818182&view=auto
==============================================================================
---
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTracker.java
(added)
+++
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTracker.java
Wed Sep 23 18:07:38 2009
@@ -0,0 +1,471 @@
+/*
+ * 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.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 $Revision$
+ * @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;
+
+ /**
+ * 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;
+
+ /**
+ * 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;
+ }
+
+ /**
+ * State mask for bundles being tracked. This field contains the ORed
values
+ * of the bundle states being tracked.
+ */
+ final int mask;
+
+ /**
+ * 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;
+ }
+
+ /**
+ * 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);
+ }
+ }
+}
Added:
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTrackerCustomizer.java
URL:
http://svn.apache.org/viewvc/camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTrackerCustomizer.java?rev=818182&view=auto
==============================================================================
---
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTrackerCustomizer.java
(added)
+++
camel/trunk/components/camel-osgi/src/main/java/org/apache/camel/osgi/tracker/BundleTrackerCustomizer.java
Wed Sep 23 18:07:38 2009
@@ -0,0 +1,104 @@
+/*
+ * 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.osgi.tracker;
+
+import org.osgi.framework.Bundle;
+import org.osgi.framework.BundleEvent;
+
+/**
+ * The <code>BundleTrackerCustomizer</code> interface allows a
+ * <code>BundleTracker</code> to customize the <code>Bundle</code>s that are
+ * tracked. A <code>BundleTrackerCustomizer</code> is called when a bundle is
+ * being added to a <code>BundleTracker</code>. The
+ * <code>BundleTrackerCustomizer</code> can then return an object for the
+ * tracked bundle. A <code>BundleTrackerCustomizer</code> is also called when a
+ * tracked bundle is modified or has been removed from a
+ * <code>BundleTracker</code>.
+ *
+ * <p>
+ * The methods in this interface may be called as the result of a
+ * <code>BundleEvent</code> being received by a <code>BundleTracker</code>.
+ * Since <code>BundleEvent</code>s are received synchronously by the
+ * <code>BundleTracker</code>, it is highly recommended that implementations of
+ * these methods do not alter bundle states while being synchronized on any
+ * object.
+ *
+ * <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 $Revision$
+ * @since 1.4
+ */
+public interface BundleTrackerCustomizer {
+ /**
+ * A bundle is being added to the <code>BundleTracker</code>.
+ *
+ * <p>
+ * This method is called before a bundle which matched the search
parameters
+ * of the <code>BundleTracker</code> is added to the
+ * <code>BundleTracker</code>. This method should return the object to
be
+ * tracked for the specified <code>Bundle</code>. The returned object is
+ * stored in the <code>BundleTracker</code> and is available from the
+ * {...@link BundleTracker#getObject(Bundle) getObject} method.
+ *
+ * @param bundle The <code>Bundle</code> being added to the
+ * <code>BundleTracker</code>.
+ * @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 object to be tracked for the specified
<code>Bundle</code>
+ * object or <code>null</code> if the specified
<code>Bundle</code>
+ * object should not be tracked.
+ */
+ public Object addingBundle(Bundle bundle, BundleEvent event);
+
+ /**
+ * A bundle tracked by the <code>BundleTracker</code> has been modified.
+ *
+ * <p>
+ * This method is called when a bundle being tracked by the
+ * <code>BundleTracker</code> has had its state modified.
+ *
+ * @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 tracked object for the specified bundle.
+ */
+ public void modifiedBundle(Bundle bundle, BundleEvent event,
+ Object object);
+
+ /**
+ * A bundle tracked by the <code>BundleTracker</code> has been removed.
+ *
+ * <p>
+ * This method is called after a bundle is no longer being tracked by
the
+ * <code>BundleTracker</code>.
+ *
+ * @param bundle The <code>Bundle</code> that has been 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 tracked object for the specified bundle.
+ */
+ public void removedBundle(Bundle bundle, BundleEvent event,
+ Object object);
+}
