001    // Copyright 2007 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.ioc.internal.services;
016    
017    import org.apache.tapestry5.ioc.Registry;
018    import org.apache.tapestry5.ioc.internal.util.OneShotLock;
019    import org.slf4j.Logger;
020    
021    import java.util.List;
022    
023    /**
024     * Startup service for Tapestry IoC: automatically invoked at {@linkplain Registry#performRegistryStartup() registry
025     * startup} to execute a series of operations, via its ordered configuration of Runnable objects.
026     */
027    public class RegistryStartup implements Runnable
028    {
029        private final Logger logger;
030    
031        private final List<Runnable> configuration;
032    
033        private final OneShotLock lock = new OneShotLock();
034    
035        public RegistryStartup(Logger logger, final List<Runnable> configuration)
036        {
037            this.logger = logger;
038            this.configuration = configuration;
039        }
040    
041        /**
042         * Invokes run() on each contributed object. If the object throws a runtime exception, it is logged but startup
043         * continues anyway. This method may only be {@linkplain OneShotLock invoked once}.
044         */
045        public void run()
046        {
047            lock.lock();
048    
049            // Do we want extra exception catching here?
050    
051            for (Runnable r : configuration)
052            {
053                try
054                {
055                    r.run();
056                }
057                catch (RuntimeException ex)
058                {
059                    logger.error(ServiceMessages.startupFailure(ex));
060                }
061            }
062    
063            // We don't need them any more since this method can only be run once. It's a insignificant
064            // savings, but still a nice thing to do.
065    
066            configuration.clear();
067        }
068    
069    }