services/eventadmin/src/main/java/org/apache/felix/eventadmin/impl/Configuration.java - karaf - Git at Google

 /*
  * 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.
  */
 package org.apache.felix.eventadmin.impl;


 import java.util.Dictionary;
 import java.util.Hashtable;
 import java.util.StringTokenizer;

 import org.apache.felix.eventadmin.impl.adapter.AbstractAdapter;
 import org.apache.felix.eventadmin.impl.adapter.BundleEventAdapter;
 import org.apache.felix.eventadmin.impl.adapter.FrameworkEventAdapter;
 import org.apache.felix.eventadmin.impl.adapter.LogEventAdapter;
 import org.apache.felix.eventadmin.impl.adapter.ServiceEventAdapter;
 import org.apache.felix.eventadmin.impl.handler.EventAdminImpl;
 import org.apache.felix.eventadmin.impl.security.SecureEventAdminFactory;
 import org.apache.felix.eventadmin.impl.tasks.DefaultThreadPool;
 import org.apache.felix.eventadmin.impl.util.LogWrapper;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.Constants;
 import org.osgi.framework.ServiceRegistration;
 import org.osgi.service.cm.ConfigurationException;
 import org.osgi.service.cm.ManagedService;
 import org.osgi.service.event.EventAdmin;
 import org.osgi.service.metatype.MetaTypeProvider;


 /**
  * The <code>Configuration</code> class encapsules the
  * configuration for the event admin.
  *
  * The service knows about the following properties which are read at bundle startup:
  * <p>
  * <p>
  *      <tt>org.apache.felix.eventadmin.ThreadPoolSize</tt> - The size of the thread
  *          pool.
  * </p>
  * The default value is 10. Increase in case of a large amount of synchronous events
  * where the <tt>EventHandler</tt> services in turn send new synchronous events in
  * the event dispatching thread or a lot of timeouts are to be expected. A value of
  * less then 2 triggers the default value. A value of 2 effectively disables thread
  * pooling.
  * </p>
  * <p>
  * <p>
  *      <tt>org.apache.felix.eventadmin.Timeout</tt> - The black-listing timeout in
  *          milliseconds
  * </p>
  * The default value is 5000. Increase or decrease at own discretion. A value of less
  * then 100 turns timeouts off. Any other value is the time in milliseconds granted
  * to each <tt>EventHandler</tt> before it gets blacklisted.
  * </p>
  * <p>
  * <p>
  *      <tt>org.apache.felix.eventadmin.RequireTopic</tt> - Are <tt>EventHandler</tt>
  *          required to be registered with a topic?
  * </p>
  * The default is <tt>true</tt>. The specification says that <tt>EventHandler</tt>
  * must register with a list of topics they are interested in. Setting this value to
  * <tt>false</tt> will enable that handlers without a topic are receiving all events
  * (i.e., they are treated the same as with a topic=*).
  * </p>
  * <p>
  * <p>
  *      <tt>org.apache.felix.eventadmin.IgnoreTimeout</tt> - Configure
  *         <tt>EventHandler</tt>s to be called without a timeout.
  * </p>
  * If a timeout is configured by default all event handlers are called using the timeout.
  * For performance optimization it is possible to configure event handlers where the
  * timeout handling is not used - this reduces the thread usage from the thread pools
  * as the timout handling requires an additional thread to call the event handler.
  * However, the application should work without this configuration property. It is a
  * pure optimization!
  * The value is a list of string (separated by comma). If the string ends with a dot,
  * all handlers in exactly this package are ignored. If the string ends with a star,
  * all handlers in this package and all subpackages are ignored. If the string neither
  * ends with a dot nor with a start, this is assumed to define an exact class name.
  *
  * These properties are read at startup and serve as a default configuration.
  * If a configuration admin is configured, the event admin can be configured
  * through the config admin.
  *
  * @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
  */
 public class Configuration
 {
     /** The PID for the event admin. */
     static final String PID = "org.apache.felix.eventadmin.impl.EventAdmin";

     static final String PROP_THREAD_POOL_SIZE = "org.apache.felix.eventadmin.ThreadPoolSize";
     static final String PROP_ASYNC_TO_SYNC_THREAD_RATIO = "org.apache.felix.eventadmin.AsyncToSyncThreadRatio";
     static final String PROP_TIMEOUT = "org.apache.felix.eventadmin.Timeout";
     static final String PROP_REQUIRE_TOPIC = "org.apache.felix.eventadmin.RequireTopic";
     static final String PROP_IGNORE_TIMEOUT = "org.apache.felix.eventadmin.IgnoreTimeout";
     static final String PROP_IGNORE_TOPIC = "org.apache.felix.eventadmin.IgnoreTopic";
     static final String PROP_LOG_LEVEL = "org.apache.felix.eventadmin.LogLevel";
     static final String PROP_ADD_TIMESTAMP = "org.apache.felix.eventadmin.AddTimestamp";
     static final String PROP_ADD_SUBJECT = "org.apache.felix.eventadmin.AddSubject";

     /** The bundle context. */
     private final BundleContext m_bundleContext;

     private int m_threadPoolSize;

     private double m_asyncToSyncThreadRatio;

     private int m_asyncThreadPoolSize;

     private int m_timeout;

     private boolean m_requireTopic;

     private String[] m_ignoreTimeout;

     private String[] m_ignoreTopics;

     private int m_logLevel;

     private boolean m_addTimestamp;

     private boolean m_addSubject;

     // The thread pool used - this is a member because we need to close it on stop
     private volatile DefaultThreadPool m_sync_pool;

     private volatile DefaultThreadPool m_async_pool;

     // The actual implementation of the service - this is a member because we need to
     // close it on stop. Note, security is not part of this implementation but is
     // added via a decorator in the start method (this is the wrapped object without
     // the wrapper).
     private volatile EventAdminImpl m_admin;

     // The registration of the security decorator factory (i.e., the service)
     private volatile ServiceRegistration m_registration;

     // all adapters
     private AbstractAdapter[] m_adapters;

     private ServiceRegistration m_managedServiceReg;

     public Configuration( BundleContext bundleContext )
     {
         m_bundleContext = bundleContext;

         // default configuration
         configure( null );
         startOrUpdate();

         // check for Configuration Admin configuration
         try
         {
             Object service = tryToCreateManagedService();
             if ( service != null )
             {
                 // add meta type provider if interfaces are available
                 Object enhancedService = tryToCreateMetaTypeProvider(service);
                 final String[] interfaceNames;
                 if ( enhancedService == null )
                 {
                     interfaceNames = new String[] {ManagedService.class.getName()};
                 }
                 else
                 {
                     interfaceNames = new String[] {ManagedService.class.getName(), MetaTypeProvider.class.getName()};
                     service = enhancedService;
                 }
                 Dictionary<String, Object> props = new Hashtable<String, Object>();
                 props.put( Constants.SERVICE_PID, PID );
                 m_managedServiceReg = m_bundleContext.registerService( interfaceNames, service, props );
             }
         }
         catch ( Throwable t )
         {
             // don't care
         }
     }

     void updateFromConfigAdmin(final Dictionary<String, ?> config)
     {
         // do this in the background as we don't want to stop
         // the config admin
         new Thread()
         {

             @Override
             public void run()
             {
                 synchronized ( Configuration.this )
                 {
                     Configuration.this.configure( config );
                     Configuration.this.startOrUpdate();
                 }
             }

         }.start();

     }

     /**
      * Configures this instance.
      */
     void configure( Dictionary<String, ?> config )
     {
         if ( config == null )
         {
             // The size of the internal thread pool. Note that we must execute
             // each synchronous event dispatch that happens in the synchronous event
             // dispatching thread in a new thread, hence a small thread pool is o.k.
             // A value of less then 2 triggers the default value. A value of 2
             // effectively disables thread pooling. Furthermore, this will be used by
             // a lazy thread pool (i.e., new threads are created when needed). Ones the
             // the size is reached and no cached thread is available new threads will
             // be created.
             m_threadPoolSize = getIntProperty(
                     PROP_THREAD_POOL_SIZE, m_bundleContext.getProperty(PROP_THREAD_POOL_SIZE), 20, 2);

             // The ratio of asynchronous to synchronous threads in the internal thread
             // pool.  Ratio must be positive and may be adjusted to represent the
             // distribution of post to send operations.  Applications with higher number
             // of post operations should have a higher ratio.
             m_asyncToSyncThreadRatio = getDoubleProperty(
                     PROP_ASYNC_TO_SYNC_THREAD_RATIO, m_bundleContext.getProperty(PROP_ASYNC_TO_SYNC_THREAD_RATIO), 0.5, 0.0);

             // The timeout in milliseconds - A value of less then 100 turns timeouts off.
             // Any other value is the time in milliseconds granted to each EventHandler
             // before it gets blacklisted.
             m_timeout = getIntProperty(PROP_TIMEOUT,
                     m_bundleContext.getProperty(PROP_TIMEOUT), 5000, Integer.MIN_VALUE);

             // Are EventHandler required to be registered with a topic? - The default is
             // true. The specification says that EventHandler must register with a list
             // of topics they are interested in. Setting this value to false will enable
             // that handlers without a topic are receiving all events
             // (i.e., they are treated the same as with a topic=*).
             m_requireTopic = getBooleanProperty(
                     m_bundleContext.getProperty(PROP_REQUIRE_TOPIC), true);
             final String value = m_bundleContext.getProperty(PROP_IGNORE_TIMEOUT);
             if ( value == null )
             {
                 m_ignoreTimeout = null;
             }
             else
             {
                 final StringTokenizer st = new StringTokenizer(value, ",");
                 m_ignoreTimeout = new String[st.countTokens()];
                 for(int i=0; i<m_ignoreTimeout.length; i++)
                 {
                     m_ignoreTimeout[i] = st.nextToken();
                 }
             }

             final String valueIgnoreTopic = m_bundleContext.getProperty(PROP_IGNORE_TOPIC);
             if ( valueIgnoreTopic == null )
             {
                 m_ignoreTopics = null;
             }
             else
             {
                 final StringTokenizer st = new StringTokenizer(valueIgnoreTopic, ",");
                 m_ignoreTopics = new String[st.countTokens()];
                 for(int i=0; i<m_ignoreTopics.length; i++)
                 {
                     m_ignoreTopics[i] = st.nextToken();
                 }
             }
             m_logLevel = getIntProperty(PROP_LOG_LEVEL,
                     m_bundleContext.getProperty(PROP_LOG_LEVEL),
                     LogWrapper.LOG_WARNING, // default log level is WARNING
                     LogWrapper.LOG_ERROR);
             m_addTimestamp = getBooleanProperty(
                     m_bundleContext.getProperty(PROP_ADD_TIMESTAMP), false);
             m_addSubject = getBooleanProperty(
                     m_bundleContext.getProperty(PROP_ADD_SUBJECT), false);
         }
         else
         {
             m_threadPoolSize = getIntProperty(PROP_THREAD_POOL_SIZE, config.get(PROP_THREAD_POOL_SIZE), 20, 2);
             m_asyncToSyncThreadRatio = getDoubleProperty(
                     PROP_ASYNC_TO_SYNC_THREAD_RATIO, m_bundleContext.getProperty(PROP_ASYNC_TO_SYNC_THREAD_RATIO), 0.5, 0.0);
             m_timeout = getIntProperty(PROP_TIMEOUT, config.get(PROP_TIMEOUT), 5000, Integer.MIN_VALUE);
             m_requireTopic = getBooleanProperty(config.get(PROP_REQUIRE_TOPIC), true);
             m_ignoreTimeout = null;
             final Object value = config.get(PROP_IGNORE_TIMEOUT);
             if ( value instanceof String )
             {
                 m_ignoreTimeout = new String[] {(String)value};
             }
             else if ( value instanceof String[] )
             {
                 m_ignoreTimeout = (String[])value;
             }
             else if ( value != null )
             {
                 LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
                         "Value for property: " + PROP_IGNORE_TIMEOUT + " is neither a string nor a string array - Using default");
             }
             m_ignoreTopics = null;
             final Object valueIT = config.get(PROP_IGNORE_TOPIC);
             if ( valueIT instanceof String )
             {
                 m_ignoreTopics = new String[] {(String)valueIT};
             }
             else if ( valueIT instanceof String[] )
             {
                 m_ignoreTopics = (String[])valueIT;
             }
             else if ( valueIT != null )
             {
                 LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
                         "Value for property: " + PROP_IGNORE_TOPIC + " is neither a string nor a string array - Using default");
             }
             m_logLevel = getIntProperty(PROP_LOG_LEVEL,
                     config.get(PROP_LOG_LEVEL),
                     LogWrapper.LOG_WARNING, // default log level is WARNING
                     LogWrapper.LOG_ERROR);
             m_addTimestamp = getBooleanProperty(
                     config.get(PROP_ADD_TIMESTAMP), false);
             m_addSubject = getBooleanProperty(
                     config.get(PROP_ADD_SUBJECT), false);
         }
         // a timeout less or equals to 100 means : disable timeout
         if ( m_timeout <= 100 )
         {
             m_timeout = 0;
         }
         m_asyncThreadPoolSize = m_threadPoolSize > 5 ? (int)Math.floor(m_threadPoolSize * m_asyncToSyncThreadRatio)  : 2;
     }

     private void startOrUpdate()
     {
         LogWrapper.getLogger().setLogLevel(m_logLevel);
         LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
                 PROP_LOG_LEVEL + "=" + m_logLevel);
         LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
                 PROP_THREAD_POOL_SIZE + "=" + m_threadPoolSize);
         LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
                 PROP_ASYNC_TO_SYNC_THREAD_RATIO + "=" + m_asyncToSyncThreadRatio);
         LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
                 "Async Pool Size=" + m_asyncThreadPoolSize);
         LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
                 PROP_TIMEOUT + "=" + m_timeout);
         LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
                 PROP_REQUIRE_TOPIC + "=" + m_requireTopic);

         // Note that this uses a lazy thread pool that will create new threads on
         // demand - in case none of its cached threads is free - until threadPoolSize
         // is reached. Subsequently, a threadPoolSize of 2 effectively disables
         // caching of threads.
         if ( m_sync_pool == null )
         {
             m_sync_pool = new DefaultThreadPool(m_threadPoolSize, true);
         }
         else
         {
             m_sync_pool.configure(m_threadPoolSize);
         }
         final int asyncThreadPoolSize = m_asyncThreadPoolSize;
         if ( m_async_pool == null )
         {
             m_async_pool = new DefaultThreadPool(asyncThreadPoolSize, false);
         }
         else
         {
             m_async_pool.configure(asyncThreadPoolSize);
         }

         if ( m_admin == null )
         {
             m_admin = new EventAdminImpl(m_bundleContext,
                     m_sync_pool,
                     m_async_pool,
                     m_timeout,
                     m_ignoreTimeout,
                     m_requireTopic,
                     m_ignoreTopics,
                     m_addTimestamp,
                     m_addSubject);

             // Finally, adapt the outside events to our kind of events as per spec
             adaptEvents(m_admin);

             // register the admin wrapped in a service factory (SecureEventAdminFactory)
             // that hands-out the m_admin object wrapped in a decorator that checks
             // appropriated permissions of each calling bundle
             m_registration = m_bundleContext.registerService(EventAdmin.class.getName(),
                     new SecureEventAdminFactory(m_admin), null);
         }
         else
         {
             m_admin.update(m_timeout, m_ignoreTimeout, m_requireTopic, m_ignoreTopics, m_addTimestamp, m_addSubject);
         }

     }

     /**
      * Called upon stopping the bundle. This will block until all pending events are
      * delivered. An IllegalStateException will be thrown on new events starting with
      * the begin of this method. However, it might take some time until we settle
      * down which is somewhat cumbersome given that the spec asks for return in
      * a timely manner.
      */
     public void destroy()
     {
         synchronized ( this )
         {
             if ( m_adapters != null )
             {
                 for(int i=0;i<m_adapters.length;i++)
                 {
                     m_adapters[i].destroy(m_bundleContext);
                 }
                 m_adapters = null;
             }
             if ( m_managedServiceReg != null )
             {
                 m_managedServiceReg.unregister();
                 m_managedServiceReg = null;
             }
             // We need to unregister manually
             if ( m_registration != null )
             {
                 m_registration.unregister();
                 m_registration = null;
             }
             if ( m_admin != null )
             {
                 m_admin.stop();
                 m_admin = null;
             }
             if (m_async_pool != null )
             {
                 m_async_pool.close();
                 m_async_pool = null;
             }
             if ( m_sync_pool != null )
             {
                 m_sync_pool.close();
                 m_sync_pool = null;
             }
         }
     }

     /**
      * Init the adapters in org.apache.felix.eventadmin.impl.adapter
      */
     private void adaptEvents(final EventAdmin admin)
     {
         m_adapters = new AbstractAdapter[4];
         m_adapters[0] = new FrameworkEventAdapter(m_bundleContext, admin);
         m_adapters[1] = new BundleEventAdapter(m_bundleContext, admin);
         m_adapters[2] = new ServiceEventAdapter(m_bundleContext, admin);
         m_adapters[3] = new LogEventAdapter(m_bundleContext, admin);
     }

     private Object tryToCreateMetaTypeProvider(final Object managedService)
     {
         try
         {
             return new MetaTypeProviderImpl((ManagedService)managedService,
                     m_threadPoolSize, m_timeout, m_requireTopic,
                     m_ignoreTimeout, m_ignoreTopics, m_asyncToSyncThreadRatio);
         }
         catch (final Throwable t)
         {
             // we simply ignore this
         }
         return null;
     }

     private Object tryToCreateManagedService()
     {
         try
         {
             return new ManagedService()
             {
                 @Override
                 public void updated( Dictionary<String, ?> properties ) throws ConfigurationException
                 {
                     updateFromConfigAdmin(properties);
                 }
             };
         }
         catch (Throwable t)
         {
             // we simply ignore this
         }
         return null;
     }

     /**
      * Returns either the parsed int from the value of the property if it is set and
      * not less then the min value or the default. Additionally, a warning is
      * generated in case the value is erroneous (i.e., can not be parsed as an int or
      * is less then the min value).
      */
     private int getIntProperty(final String key, final Object value,
                                final int defaultValue, final int min)
     {
         if(null != value)
         {
             final int result;
             if ( value instanceof Integer )
             {
                 result = ((Integer)value).intValue();
             }
             else
             {
                 try
                 {
                     result = Integer.parseInt(value.toString());
                 }
                 catch (NumberFormatException e)
                 {
                     LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
                             "Unable to parse property: " + key + " - Using default", e);
                     return defaultValue;
                 }
             }
             if(result >= min)
             {
                 return result;
             }

             LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
                     "Value for property: " + key + " is to low - Using default");
         }

         return defaultValue;
     }

     /**
      * Returns either the parsed double from the value of the property if it is set and
      * not less then the min value or the default. Additionally, a warning is
      * generated in case the value is erroneous (i.e., can not be parsed as an double or
      * is less then the min value).
      */
     private double getDoubleProperty(final String key, final Object value,
                                      final double defaultValue, final double min)
     {
         if(null != value)
         {
             final double result;
             if ( value instanceof Double )
             {
                 result = ((Double)value).doubleValue();
             }
             else
             {
                 try
                 {
                     result = Double.parseDouble(value.toString());
                 }
                 catch (NumberFormatException e)
                 {
                     LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
                             "Unable to parse property: " + key + " - Using default", e);
                     return defaultValue;
                 }
             }
             if(result >= min)
             {
                 return result;
             }

             LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
                     "Value for property: " + key + " is to low - Using default");
         }

         return defaultValue;
     }

     /**
      * Returns true if the value of the property is set and is either 1, true, or yes
      * Returns false if the value of the property is set and is either 0, false, or no
      * Returns the defaultValue otherwise
      */
     private boolean getBooleanProperty(final Object obj,
                                        final boolean defaultValue)
     {
         if(null != obj)
         {
             if ( obj instanceof Boolean )
             {
                 return ((Boolean)obj).booleanValue();
             }
             String value = obj.toString().trim().toLowerCase();

             if(0 < value.length() && ("0".equals(value) || "false".equals(value)
                     || "no".equals(value)))
             {
                 return false;
             }

             if(0 < value.length() && ("1".equals(value) || "true".equals(value)
                     || "yes".equals(value)))
             {
                 return true;
             }
         }

         return defaultValue;
     }
 }
	/*
	* 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.
	*/
	package org.apache.felix.eventadmin.impl;


	import java.util.Dictionary;
	import java.util.Hashtable;
	import java.util.StringTokenizer;

	import org.apache.felix.eventadmin.impl.adapter.AbstractAdapter;
	import org.apache.felix.eventadmin.impl.adapter.BundleEventAdapter;
	import org.apache.felix.eventadmin.impl.adapter.FrameworkEventAdapter;
	import org.apache.felix.eventadmin.impl.adapter.LogEventAdapter;
	import org.apache.felix.eventadmin.impl.adapter.ServiceEventAdapter;
	import org.apache.felix.eventadmin.impl.handler.EventAdminImpl;
	import org.apache.felix.eventadmin.impl.security.SecureEventAdminFactory;
	import org.apache.felix.eventadmin.impl.tasks.DefaultThreadPool;
	import org.apache.felix.eventadmin.impl.util.LogWrapper;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.Constants;
	import org.osgi.framework.ServiceRegistration;
	import org.osgi.service.cm.ConfigurationException;
	import org.osgi.service.cm.ManagedService;
	import org.osgi.service.event.EventAdmin;
	import org.osgi.service.metatype.MetaTypeProvider;


	/**
	* The <code>Configuration</code> class encapsules the
	* configuration for the event admin.
	*
	* The service knows about the following properties which are read at bundle startup:
	* <p>
	* <p>
	* <tt>org.apache.felix.eventadmin.ThreadPoolSize</tt> - The size of the thread
	* pool.
	* </p>
	* The default value is 10. Increase in case of a large amount of synchronous events
	* where the <tt>EventHandler</tt> services in turn send new synchronous events in
	* the event dispatching thread or a lot of timeouts are to be expected. A value of
	* less then 2 triggers the default value. A value of 2 effectively disables thread
	* pooling.
	* </p>
	* <p>
	* <p>
	* <tt>org.apache.felix.eventadmin.Timeout</tt> - The black-listing timeout in
	* milliseconds
	* </p>
	* The default value is 5000. Increase or decrease at own discretion. A value of less
	* then 100 turns timeouts off. Any other value is the time in milliseconds granted
	* to each <tt>EventHandler</tt> before it gets blacklisted.
	* </p>
	* <p>
	* <p>
	* <tt>org.apache.felix.eventadmin.RequireTopic</tt> - Are <tt>EventHandler</tt>
	* required to be registered with a topic?
	* </p>
	* The default is <tt>true</tt>. The specification says that <tt>EventHandler</tt>
	* must register with a list of topics they are interested in. Setting this value to
	* <tt>false</tt> will enable that handlers without a topic are receiving all events
	* (i.e., they are treated the same as with a topic=*).
	* </p>
	* <p>
	* <p>
	* <tt>org.apache.felix.eventadmin.IgnoreTimeout</tt> - Configure
	* <tt>EventHandler</tt>s to be called without a timeout.
	* </p>
	* If a timeout is configured by default all event handlers are called using the timeout.
	* For performance optimization it is possible to configure event handlers where the
	* timeout handling is not used - this reduces the thread usage from the thread pools
	* as the timout handling requires an additional thread to call the event handler.
	* However, the application should work without this configuration property. It is a
	* pure optimization!
	* The value is a list of string (separated by comma). If the string ends with a dot,
	* all handlers in exactly this package are ignored. If the string ends with a star,
	* all handlers in this package and all subpackages are ignored. If the string neither
	* ends with a dot nor with a start, this is assumed to define an exact class name.
	*
	* These properties are read at startup and serve as a default configuration.
	* If a configuration admin is configured, the event admin can be configured
	* through the config admin.
	*
	* @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
	*/
	public class Configuration
	{
	/** The PID for the event admin. */
	static final String PID = "org.apache.felix.eventadmin.impl.EventAdmin";

	static final String PROP_THREAD_POOL_SIZE = "org.apache.felix.eventadmin.ThreadPoolSize";
	static final String PROP_ASYNC_TO_SYNC_THREAD_RATIO = "org.apache.felix.eventadmin.AsyncToSyncThreadRatio";
	static final String PROP_TIMEOUT = "org.apache.felix.eventadmin.Timeout";
	static final String PROP_REQUIRE_TOPIC = "org.apache.felix.eventadmin.RequireTopic";
	static final String PROP_IGNORE_TIMEOUT = "org.apache.felix.eventadmin.IgnoreTimeout";
	static final String PROP_IGNORE_TOPIC = "org.apache.felix.eventadmin.IgnoreTopic";
	static final String PROP_LOG_LEVEL = "org.apache.felix.eventadmin.LogLevel";
	static final String PROP_ADD_TIMESTAMP = "org.apache.felix.eventadmin.AddTimestamp";
	static final String PROP_ADD_SUBJECT = "org.apache.felix.eventadmin.AddSubject";

	/** The bundle context. */
	private final BundleContext m_bundleContext;

	private int m_threadPoolSize;

	private double m_asyncToSyncThreadRatio;

	private int m_asyncThreadPoolSize;

	private int m_timeout;

	private boolean m_requireTopic;

	private String[] m_ignoreTimeout;

	private String[] m_ignoreTopics;

	private int m_logLevel;

	private boolean m_addTimestamp;

	private boolean m_addSubject;

	// The thread pool used - this is a member because we need to close it on stop
	private volatile DefaultThreadPool m_sync_pool;

	private volatile DefaultThreadPool m_async_pool;

	// The actual implementation of the service - this is a member because we need to
	// close it on stop. Note, security is not part of this implementation but is
	// added via a decorator in the start method (this is the wrapped object without
	// the wrapper).
	private volatile EventAdminImpl m_admin;

	// The registration of the security decorator factory (i.e., the service)
	private volatile ServiceRegistration m_registration;

	// all adapters
	private AbstractAdapter[] m_adapters;

	private ServiceRegistration m_managedServiceReg;

	public Configuration( BundleContext bundleContext )
	{
	m_bundleContext = bundleContext;

	// default configuration
	configure( null );
	startOrUpdate();

	// check for Configuration Admin configuration
	try
	{
	Object service = tryToCreateManagedService();
	if ( service != null )
	{
	// add meta type provider if interfaces are available
	Object enhancedService = tryToCreateMetaTypeProvider(service);
	final String[] interfaceNames;
	if ( enhancedService == null )
	{
	interfaceNames = new String[] {ManagedService.class.getName()};
	}
	else
	{
	interfaceNames = new String[] {ManagedService.class.getName(), MetaTypeProvider.class.getName()};
	service = enhancedService;
	}
	Dictionary<String, Object> props = new Hashtable<String, Object>();
	props.put( Constants.SERVICE_PID, PID );
	m_managedServiceReg = m_bundleContext.registerService( interfaceNames, service, props );
	}
	}
	catch ( Throwable t )
	{
	// don't care
	}
	}

	void updateFromConfigAdmin(final Dictionary<String, ?> config)
	{
	// do this in the background as we don't want to stop
	// the config admin
	new Thread()
	{

	@Override
	public void run()
	{
	synchronized ( Configuration.this )
	{
	Configuration.this.configure( config );
	Configuration.this.startOrUpdate();
	}
	}

	}.start();

	}

	/**
	* Configures this instance.
	*/
	void configure( Dictionary<String, ?> config )
	{
	if ( config == null )
	{
	// The size of the internal thread pool. Note that we must execute
	// each synchronous event dispatch that happens in the synchronous event
	// dispatching thread in a new thread, hence a small thread pool is o.k.
	// A value of less then 2 triggers the default value. A value of 2
	// effectively disables thread pooling. Furthermore, this will be used by
	// a lazy thread pool (i.e., new threads are created when needed). Ones the
	// the size is reached and no cached thread is available new threads will
	// be created.
	m_threadPoolSize = getIntProperty(
	PROP_THREAD_POOL_SIZE, m_bundleContext.getProperty(PROP_THREAD_POOL_SIZE), 20, 2);

	// The ratio of asynchronous to synchronous threads in the internal thread
	// pool. Ratio must be positive and may be adjusted to represent the
	// distribution of post to send operations. Applications with higher number
	// of post operations should have a higher ratio.
	m_asyncToSyncThreadRatio = getDoubleProperty(
	PROP_ASYNC_TO_SYNC_THREAD_RATIO, m_bundleContext.getProperty(PROP_ASYNC_TO_SYNC_THREAD_RATIO), 0.5, 0.0);

	// The timeout in milliseconds - A value of less then 100 turns timeouts off.
	// Any other value is the time in milliseconds granted to each EventHandler
	// before it gets blacklisted.
	m_timeout = getIntProperty(PROP_TIMEOUT,
	m_bundleContext.getProperty(PROP_TIMEOUT), 5000, Integer.MIN_VALUE);

	// Are EventHandler required to be registered with a topic? - The default is
	// true. The specification says that EventHandler must register with a list
	// of topics they are interested in. Setting this value to false will enable
	// that handlers without a topic are receiving all events
	// (i.e., they are treated the same as with a topic=*).
	m_requireTopic = getBooleanProperty(
	m_bundleContext.getProperty(PROP_REQUIRE_TOPIC), true);
	final String value = m_bundleContext.getProperty(PROP_IGNORE_TIMEOUT);
	if ( value == null )
	{
	m_ignoreTimeout = null;
	}
	else
	{
	final StringTokenizer st = new StringTokenizer(value, ",");
	m_ignoreTimeout = new String[st.countTokens()];
	for(int i=0; i<m_ignoreTimeout.length; i++)
	{
	m_ignoreTimeout[i] = st.nextToken();
	}
	}

	final String valueIgnoreTopic = m_bundleContext.getProperty(PROP_IGNORE_TOPIC);
	if ( valueIgnoreTopic == null )
	{
	m_ignoreTopics = null;
	}
	else
	{
	final StringTokenizer st = new StringTokenizer(valueIgnoreTopic, ",");
	m_ignoreTopics = new String[st.countTokens()];
	for(int i=0; i<m_ignoreTopics.length; i++)
	{
	m_ignoreTopics[i] = st.nextToken();
	}
	}
	m_logLevel = getIntProperty(PROP_LOG_LEVEL,
	m_bundleContext.getProperty(PROP_LOG_LEVEL),
	LogWrapper.LOG_WARNING, // default log level is WARNING
	LogWrapper.LOG_ERROR);
	m_addTimestamp = getBooleanProperty(
	m_bundleContext.getProperty(PROP_ADD_TIMESTAMP), false);
	m_addSubject = getBooleanProperty(
	m_bundleContext.getProperty(PROP_ADD_SUBJECT), false);
	}
	else
	{
	m_threadPoolSize = getIntProperty(PROP_THREAD_POOL_SIZE, config.get(PROP_THREAD_POOL_SIZE), 20, 2);
	m_asyncToSyncThreadRatio = getDoubleProperty(
	PROP_ASYNC_TO_SYNC_THREAD_RATIO, m_bundleContext.getProperty(PROP_ASYNC_TO_SYNC_THREAD_RATIO), 0.5, 0.0);
	m_timeout = getIntProperty(PROP_TIMEOUT, config.get(PROP_TIMEOUT), 5000, Integer.MIN_VALUE);
	m_requireTopic = getBooleanProperty(config.get(PROP_REQUIRE_TOPIC), true);
	m_ignoreTimeout = null;
	final Object value = config.get(PROP_IGNORE_TIMEOUT);
	if ( value instanceof String )
	{
	m_ignoreTimeout = new String[] {(String)value};
	}
	else if ( value instanceof String[] )
	{
	m_ignoreTimeout = (String[])value;
	}
	else if ( value != null )
	{
	LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
	"Value for property: " + PROP_IGNORE_TIMEOUT + " is neither a string nor a string array - Using default");
	}
	m_ignoreTopics = null;
	final Object valueIT = config.get(PROP_IGNORE_TOPIC);
	if ( valueIT instanceof String )
	{
	m_ignoreTopics = new String[] {(String)valueIT};
	}
	else if ( valueIT instanceof String[] )
	{
	m_ignoreTopics = (String[])valueIT;
	}
	else if ( valueIT != null )
	{
	LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
	"Value for property: " + PROP_IGNORE_TOPIC + " is neither a string nor a string array - Using default");
	}
	m_logLevel = getIntProperty(PROP_LOG_LEVEL,
	config.get(PROP_LOG_LEVEL),
	LogWrapper.LOG_WARNING, // default log level is WARNING
	LogWrapper.LOG_ERROR);
	m_addTimestamp = getBooleanProperty(
	config.get(PROP_ADD_TIMESTAMP), false);
	m_addSubject = getBooleanProperty(
	config.get(PROP_ADD_SUBJECT), false);
	}
	// a timeout less or equals to 100 means : disable timeout
	if ( m_timeout <= 100 )
	{
	m_timeout = 0;
	}
	m_asyncThreadPoolSize = m_threadPoolSize > 5 ? (int)Math.floor(m_threadPoolSize * m_asyncToSyncThreadRatio) : 2;
	}

	private void startOrUpdate()
	{
	LogWrapper.getLogger().setLogLevel(m_logLevel);
	LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
	PROP_LOG_LEVEL + "=" + m_logLevel);
	LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
	PROP_THREAD_POOL_SIZE + "=" + m_threadPoolSize);
	LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
	PROP_ASYNC_TO_SYNC_THREAD_RATIO + "=" + m_asyncToSyncThreadRatio);
	LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
	"Async Pool Size=" + m_asyncThreadPoolSize);
	LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
	PROP_TIMEOUT + "=" + m_timeout);
	LogWrapper.getLogger().log(LogWrapper.LOG_DEBUG,
	PROP_REQUIRE_TOPIC + "=" + m_requireTopic);

	// Note that this uses a lazy thread pool that will create new threads on
	// demand - in case none of its cached threads is free - until threadPoolSize
	// is reached. Subsequently, a threadPoolSize of 2 effectively disables
	// caching of threads.
	if ( m_sync_pool == null )
	{
	m_sync_pool = new DefaultThreadPool(m_threadPoolSize, true);
	}
	else
	{
	m_sync_pool.configure(m_threadPoolSize);
	}
	final int asyncThreadPoolSize = m_asyncThreadPoolSize;
	if ( m_async_pool == null )
	{
	m_async_pool = new DefaultThreadPool(asyncThreadPoolSize, false);
	}
	else
	{
	m_async_pool.configure(asyncThreadPoolSize);
	}

	if ( m_admin == null )
	{
	m_admin = new EventAdminImpl(m_bundleContext,
	m_sync_pool,
	m_async_pool,
	m_timeout,
	m_ignoreTimeout,
	m_requireTopic,
	m_ignoreTopics,
	m_addTimestamp,
	m_addSubject);

	// Finally, adapt the outside events to our kind of events as per spec
	adaptEvents(m_admin);

	// register the admin wrapped in a service factory (SecureEventAdminFactory)
	// that hands-out the m_admin object wrapped in a decorator that checks
	// appropriated permissions of each calling bundle
	m_registration = m_bundleContext.registerService(EventAdmin.class.getName(),
	new SecureEventAdminFactory(m_admin), null);
	}
	else
	{
	m_admin.update(m_timeout, m_ignoreTimeout, m_requireTopic, m_ignoreTopics, m_addTimestamp, m_addSubject);
	}

	}

	/**
	* Called upon stopping the bundle. This will block until all pending events are
	* delivered. An IllegalStateException will be thrown on new events starting with
	* the begin of this method. However, it might take some time until we settle
	* down which is somewhat cumbersome given that the spec asks for return in
	* a timely manner.
	*/
	public void destroy()
	{
	synchronized ( this )
	{
	if ( m_adapters != null )
	{
	for(int i=0;i<m_adapters.length;i++)
	{
	m_adapters[i].destroy(m_bundleContext);
	}
	m_adapters = null;
	}
	if ( m_managedServiceReg != null )
	{
	m_managedServiceReg.unregister();
	m_managedServiceReg = null;
	}
	// We need to unregister manually
	if ( m_registration != null )
	{
	m_registration.unregister();
	m_registration = null;
	}
	if ( m_admin != null )
	{
	m_admin.stop();
	m_admin = null;
	}
	if (m_async_pool != null )
	{
	m_async_pool.close();
	m_async_pool = null;
	}
	if ( m_sync_pool != null )
	{
	m_sync_pool.close();
	m_sync_pool = null;
	}
	}
	}

	/**
	* Init the adapters in org.apache.felix.eventadmin.impl.adapter
	*/
	private void adaptEvents(final EventAdmin admin)
	{
	m_adapters = new AbstractAdapter[4];
	m_adapters[0] = new FrameworkEventAdapter(m_bundleContext, admin);
	m_adapters[1] = new BundleEventAdapter(m_bundleContext, admin);
	m_adapters[2] = new ServiceEventAdapter(m_bundleContext, admin);
	m_adapters[3] = new LogEventAdapter(m_bundleContext, admin);
	}

	private Object tryToCreateMetaTypeProvider(final Object managedService)
	{
	try
	{
	return new MetaTypeProviderImpl((ManagedService)managedService,
	m_threadPoolSize, m_timeout, m_requireTopic,
	m_ignoreTimeout, m_ignoreTopics, m_asyncToSyncThreadRatio);
	}
	catch (final Throwable t)
	{
	// we simply ignore this
	}
	return null;
	}

	private Object tryToCreateManagedService()
	{
	try
	{
	return new ManagedService()
	{
	@Override
	public void updated( Dictionary<String, ?> properties ) throws ConfigurationException
	{
	updateFromConfigAdmin(properties);
	}
	};
	}
	catch (Throwable t)
	{
	// we simply ignore this
	}
	return null;
	}

	/**
	* Returns either the parsed int from the value of the property if it is set and
	* not less then the min value or the default. Additionally, a warning is
	* generated in case the value is erroneous (i.e., can not be parsed as an int or
	* is less then the min value).
	*/
	private int getIntProperty(final String key, final Object value,
	final int defaultValue, final int min)
	{
	if(null != value)
	{
	final int result;
	if ( value instanceof Integer )
	{
	result = ((Integer)value).intValue();
	}
	else
	{
	try
	{
	result = Integer.parseInt(value.toString());
	}
	catch (NumberFormatException e)
	{
	LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
	"Unable to parse property: " + key + " - Using default", e);
	return defaultValue;
	}
	}
	if(result >= min)
	{
	return result;
	}

	LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
	"Value for property: " + key + " is to low - Using default");
	}

	return defaultValue;
	}

	/**
	* Returns either the parsed double from the value of the property if it is set and
	* not less then the min value or the default. Additionally, a warning is
	* generated in case the value is erroneous (i.e., can not be parsed as an double or
	* is less then the min value).
	*/
	private double getDoubleProperty(final String key, final Object value,
	final double defaultValue, final double min)
	{
	if(null != value)
	{
	final double result;
	if ( value instanceof Double )
	{
	result = ((Double)value).doubleValue();
	}
	else
	{
	try
	{
	result = Double.parseDouble(value.toString());
	}
	catch (NumberFormatException e)
	{
	LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
	"Unable to parse property: " + key + " - Using default", e);
	return defaultValue;
	}
	}
	if(result >= min)
	{
	return result;
	}

	LogWrapper.getLogger().log(LogWrapper.LOG_WARNING,
	"Value for property: " + key + " is to low - Using default");
	}

	return defaultValue;
	}

	/**
	* Returns true if the value of the property is set and is either 1, true, or yes
	* Returns false if the value of the property is set and is either 0, false, or no
	* Returns the defaultValue otherwise
	*/
	private boolean getBooleanProperty(final Object obj,
	final boolean defaultValue)
	{
	if(null != obj)
	{
	if ( obj instanceof Boolean )
	{
	return ((Boolean)obj).booleanValue();
	}
	String value = obj.toString().trim().toLowerCase();

	if(0 < value.length() && ("0".equals(value) \|\| "false".equals(value)
	\|\| "no".equals(value)))
	{
	return false;
	}

	if(0 < value.length() && ("1".equals(value) \|\| "true".equals(value)
	\|\| "yes".equals(value)))
	{
	return true;
	}
	}

	return defaultValue;
	}
	}