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
015package org.apache.tapestry5.ioc.internal.services;
016
017import org.apache.tapestry5.ioc.Registry;
018import org.apache.tapestry5.ioc.internal.util.OneShotLock;
019import org.slf4j.Logger;
020
021import 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 */
027public 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}