useradmin/useradmin/src/main/java/org/apache/felix/useradmin/osgi/UserAdminListenerListHelper.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.useradmin.osgi;


import org.apache.felix.useradmin.impl.UserAdminListenerList;
import org.osgi.framework.BundleContext;
import org.osgi.service.useradmin.UserAdminListener;
import org.osgi.util.tracker.ServiceTracker;

/**
 * Wraps a {@link ServiceTracker} as an {@link UserAdminListenerList} to allow 
 * it to be used as a "normal" service without having to worry about the 
 * existence of any {@link UserAdminListener}s.
 */
final class UserAdminListenerListHelper extends ServiceTracker implements UserAdminListenerList {

    /**
     * Creates a new {@link UserAdminListenerListHelper} instance.
     * 
     * @param context the bundle context to use, cannot be <code>null</code>.
     */
    public UserAdminListenerListHelper(BundleContext context) {
        super(context, UserAdminListener.class.getName(), null /* customizer */);
    }

    /**
     * {@inheritDoc}
     */
    public UserAdminListener[] getListeners() {
        Object[] services = getServices();
        if (services == null) {
            return new UserAdminListener[0];
        }

        UserAdminListener[] result = new UserAdminListener[services.length];
        for (int i = 0; i < services.length; i++) {
            result[i] = (UserAdminListener) services[i];
        }

        return result;
    }
}