listeners.java

OSGI这是一个中间件,与UPNP齐名,是用于移植到嵌入式平台之上

/*
 * Copyright (c) 2003-2004, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.knopflerfish.framework;

import java.security.*;

import java.util.Collection;
import java.util.Set;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashSet;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Dictionary;
import java.util.Enumeration;
import java.util.Vector;
import java.util.Hashtable;
import java.util.EventListener;

import org.osgi.framework.*;

/**
 * Here we handle all listeners that bundles have registered.
 *
 * @author Jan Stein
 */
public class Listeners
  implements BundleListener, FrameworkListener, ServiceListener {

  /**
   * All bundle event listeners.
   */
  private HashSet bundleListeners = new HashSet();
  private HashSet syncBundleListeners = new HashSet();

  /**
   * All framework event listeners.
   */
  private HashSet frameworkListeners = new HashSet();

  /**
   * All service event listeners.
   */
  private ServiceListenerState serviceListeners = new ServiceListenerState();


  /**
   * Add a bundle listener to current framework.
   *
   * @param bundle Who wants to add listener.
   * @param listener Object to add.
   */
  void addBundleListener(Bundle bundle, BundleListener listener) {
    ListenerEntry le = new ListenerEntry(bundle, listener);
    if (listener instanceof SynchronousBundleListener) {
      synchronized (syncBundleListeners) {
	syncBundleListeners.add(le);
      }
    } else {
      synchronized (bundleListeners) {
	bundleListeners.add(le);
      }
    }
  }


  /**
   * Remove bundle listener from current framework. Silently ignore
   * if listener doesn't exist. If listener is registered more than
   * once remove one instances.
   *
   * @param bundle Who wants to remove listener.
   * @param listener Object to remove.
   */
  void removeBundleListener(Bundle bundle, BundleListener listener) {
    ListenerEntry le = new ListenerEntry(bundle, listener);
    if (listener instanceof SynchronousBundleListener) {
      synchronized (syncBundleListeners) {
	syncBundleListeners.remove(le);
      }
    } else {
      synchronized (bundleListeners) {
	bundleListeners.remove(le);
      }
    }
  }


  /**
   * Add a bundle listener to current framework.
   *
   * @param bundle Who wants to add listener.
   * @param listener Object to add.
   */
  void addFrameworkListener(Bundle bundle, FrameworkListener listener) {
    ListenerEntry le = new ListenerEntry(bundle, listener);
    synchronized (frameworkListeners) {
      frameworkListeners.add(le);
    }
  }


  /**
   * Remove framework listener from current framework. Silently ignore
   * if listener doesn't exist. If listener is registered more than
   * once remove all instances.
   *
   * @param bundle Who wants to remove listener.
   * @param listener Object to remove.
   */
  void removeFrameworkListener(Bundle bundle, FrameworkListener listener) {
    synchronized (frameworkListeners) {
      frameworkListeners.remove(new ListenerEntry(bundle, listener));
    }
  }


  /**
   * Add a service listener with filter to current framework.
   * If no filter is wanted, call with filter param set to null.
   *
   * @param bundle Who wants to add listener.
   * @param listener Object to add.
   * @param filter LDAP String used for filtering event before calling listener.
   */
  void addServiceListener(Bundle bundle, ServiceListener listener, String filter)
    throws InvalidSyntaxException {
    serviceListeners.add(bundle, listener, filter);
  }


  /**
   * Remove service listener from current framework. Silently ignore
   * if listener doesn't exist. If listener is registered more than
   * once remove all instances.
   *
   * @param bundle Who wants to remove listener.
   * @param listener Object to remove.
   */
  void removeServiceListener(Bundle bundle, ServiceListener listener) {
    serviceListeners.remove(bundle, listener);
  }


  /**
   * Remove all listener registered by a bundle in the current framework.
   *
   * @param b Bundle which listeners we want to remove.
   */
  void removeAllListeners(Bundle b) {
    removeAllListeners(syncBundleListeners, b);
    removeAllListeners(bundleListeners, b);
    removeAllListeners(frameworkListeners, b);
    serviceListeners.removeAll(b);
  }

  /**
   * Convenience method for throwing framework error event.
   *
   * @param b Bundle which caused the error.
   * @param t Throwable generated.
   */
  void frameworkError(Bundle b, Throwable t) {
    frameworkEvent(new FrameworkEvent(FrameworkEvent.ERROR, b, t));
  }

  //
  // BundleListener interface
  //

  /**
   * Receive notification that a bundle has had a change occur in it's lifecycle.
   *
   * @see org.osgi.framework.BundleListener#bundleChanged
   */
  public void bundleChanged(final BundleEvent evt) {
    ListenerEntry [] bl, tmp;
    synchronized (bundleListeners) {
      tmp = new ListenerEntry[bundleListeners.size()];
      bundleListeners.toArray(tmp);
    }
    synchronized (syncBundleListeners) {
      bl = new ListenerEntry[tmp.length + syncBundleListeners.size()];
      syncBundleListeners.toArray(bl);
    }
    System.arraycopy(tmp, 0, bl, bl.length - tmp.length, tmp.length);
    for (int i = 0; i < bl.length; i++) {
      final ListenerEntry l = bl[i];
      try {
	AccessController.doPrivileged(new PrivilegedAction() {
	    public Object run() {
	      ((BundleListener)l.listener).bundleChanged(evt);
	      return null;
	    }
	  });
      } catch (Throwable pe) {
	frameworkError(l.bundle, pe);
      }
    }
  }

  //
  // FrameworkListener interface
  //

  /**
   * Receive notification of a general framework event.
   *
   * @see org.osgi.framework.FrameworkListener#frameworkEvent
   */
  public void frameworkEvent(final FrameworkEvent evt) {
    if (Debug.errors) {
      if (evt.getType() == FrameworkEvent.ERROR) {
	Debug.println("errors - FrameworkErrorEvent bundle #" + evt.getBundle().getBundleId());
	Debug.printStackTrace("errors - FrameworkErrorEvent throwable: ", evt.getThrowable());
      }
    }
    ListenerEntry [] fl;
    synchronized (frameworkListeners) {
      fl = new ListenerEntry[frameworkListeners.size()];
      frameworkListeners.toArray(fl);
    }
    for (int i = 0; i < fl.length; i++) {
      final ListenerEntry l = fl[i];
      try {
	AccessController.doPrivileged(new PrivilegedAction() {
	    public Object run() {
	      ((FrameworkListener)l.listener).frameworkEvent(evt);
	      return null;
	    }
	  });
      } catch (Throwable pe) {
	// We can't report Error events again, since we probably would
	// go into a infinite loop.
	if (evt.getType() != FrameworkEvent.ERROR) {
	  frameworkError(l.bundle, pe);
	}
      }
    }
  }

  //
  // ServiceListener interface
  //

  /**
   * Receive notification that a service has had a change occur in it's lifecycle.
   *
   * @see org.osgi.framework.ServiceListener#serviceChanged
   */
  public void serviceChanged(final ServiceEvent evt) {
    ServiceReferenceImpl sr = (ServiceReferenceImpl)evt.getServiceReference();
    String[] c = (String[])sr.getProperty(Constants.OBJECTCLASS);
    Permission[] perms = new Permission[c.length];
    for (int i = 0; i < c.length; i++) {
      perms[i] = new ServicePermission(c[i], ServicePermission.GET);
    }
    Set sl = serviceListeners.getMatchingListeners(evt);
    int n = 0;
    for (Iterator it = sl.iterator(); it.hasNext(); n++) {
      final ServiceListenerEntry l = (ServiceListenerEntry)it.next();
      try {
	for (int j = 0; j < c.length; j++) {
	  if (l.bundle.hasPermission(perms[j])) {
	    try {
	      AccessController.doPrivileged(new PrivilegedAction() {
		  public Object run() {
		    ((ServiceListener)l.listener).serviceChanged(evt);
		    return null;
		  }
		});
	    } catch (Throwable pe) {
	      frameworkError(l.bundle, pe);
	    }
	    break;
	  }
	}