001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.xbean.kernel.standard;
018    
019    import java.util.Collections;
020    import java.util.Iterator;
021    import java.util.Set;
022    
023    import java.util.concurrent.locks.Lock;
024    import org.apache.xbean.kernel.Kernel;
025    import org.apache.xbean.kernel.ServiceCondition;
026    import org.apache.xbean.kernel.ServiceFactory;
027    import org.apache.xbean.kernel.ServiceName;
028    
029    /**
030     * A special sub-class of AggregateCondition used to manage the stop conditions of a non-restartable service.  This class
031     * will update stop conditions to reflect the stop conditions currently registered with the service factory, when the
032     * initialized or getUnsatisfied methods are called.
033     *
034     * @author Dain Sundstrom
035     * @version $Id$
036     * @since 2.0
037     */
038    public class NonRestartableStopCondition extends AggregateCondition {
039        private final ServiceFactory serviceFactory;
040    
041        /**
042         * Creates a NonRestartableStopCondition.
043         *
044         * @param kernel the kernel in which the service is registered
045         * @param serviceName the name of the service
046         * @param classLoader the class loader for the service
047         * @param lock the lock for the service manager
048         * @param serviceFactory the service factory for the service
049         */
050        public NonRestartableStopCondition(Kernel kernel, ServiceName serviceName, ClassLoader classLoader, Lock lock, ServiceFactory serviceFactory) {
051            super(kernel, serviceName, classLoader, lock, Collections.EMPTY_SET);
052            this.serviceFactory = serviceFactory;
053        }
054    
055        /**
056         * Throws UnsupportedOperationException.  Initialize is not a valid operation for a NonRestartableStopCondition
057         *
058         * @throws UnsupportedOperationException always
059         */
060        public synchronized void initialize() throws UnsupportedOperationException {
061            throw new UnsupportedOperationException("initialize should never be called on a NonRestartableStopCondition");
062        }
063    
064        /**
065         * {@inheritDoc}
066         */
067        public synchronized Set getUnsatisfied() {
068            updateConditions();
069            return super.getUnsatisfied();
070        }
071    
072        private void updateConditions() {
073            if (isDestroyed()) throw new IllegalStateException("destroyed");
074    
075            Set conditions = getConditions();
076    
077            // add the new conditions
078            Set stopConditions = serviceFactory.getStopConditions();
079            for (Iterator iterator = stopConditions.iterator(); iterator.hasNext();) {
080                ServiceCondition condition = (ServiceCondition) iterator.next();
081                if (!conditions.contains(condition)) {
082                    addCondition(condition);
083                }
084            }
085    
086            // remove the conditions that were dropped
087            for (Iterator iterator = conditions.iterator(); iterator.hasNext();) {
088                ServiceCondition serviceCondition = (ServiceCondition) iterator.next();
089                if (!stopConditions.contains(serviceCondition)) {
090                    removeCondition(serviceCondition);
091                }
092            }
093        }
094    
095    }