http/whiteboard/src/main/java/org/apache/felix/http/whiteboard/internal/tracker/ListenersTracker.java

/*
 * 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.http.whiteboard.internal.tracker;

import java.util.EventListener;

import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletRequestAttributeListener;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionListener;

import org.apache.felix.http.whiteboard.internal.manager.ExtenderManager;
import org.osgi.framework.BundleContext;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceReference;
import org.osgi.service.http.whiteboard.HttpWhiteboardConstants;

/**
 * Implementation of the Apache Felix proprietary whiteboard for listeners
 */
public class ListenersTracker extends AbstractTracker<EventListener>
{

    private final ExtenderManager manager;

    private static org.osgi.framework.Filter createFilter(final BundleContext btx)
    {
        try
        {
            return btx.createFilter(String.format("(&" +
                                                   "(!(%s=*))" +
                                                   "(|(objectClass=%s)(objectClass=%s)(objectClass=%s)(objectClass=%s)(objectClass=%s))" +
                                                   ")",
                    HttpWhiteboardConstants.HTTP_WHITEBOARD_LISTENER,
                    HttpSessionAttributeListener.class.getName(),
                    HttpSessionListener.class.getName(),
                    ServletContextAttributeListener.class.getName(),
                    ServletRequestAttributeListener.class.getName(),
                    ServletRequestListener.class.getName()));
        }
        catch ( final InvalidSyntaxException ise)
        {
            // we can safely ignore it as the above filter is a constant
        }
        return null; // we never get here - and if, we get an NPE which is fine
    }

    public ListenersTracker(final BundleContext context,
            final ExtenderManager manager)
    {
        super(context, createFilter(context));
        this.manager = manager;
    }

    @Override
    protected void added(final EventListener service, final ServiceReference<EventListener> ref)
    {
        logDeprecationWarning("Listener", service, ref);
        this.manager.addListeners(service, ref);
    }

    @Override
    protected void removed(final EventListener service, final ServiceReference<EventListener> ref)
    {
        this.manager.removeListeners(ref);
    }
}