001// Copyright 2007-2013 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.apache.tapestry5.ioc.util.ExceptionUtils;
020import org.slf4j.Logger;
021
022import java.util.List;
023
024/**
025 * Startup service for Tapestry IoC: automatically invoked at {@linkplain Registry#performRegistryStartup() registry
026 * startup} to execute a series of operations, via its ordered configuration of Runnable objects.
027 */
028public class RegistryStartup implements Runnable
029{
030    private final Logger logger;
031
032    private final List<Runnable> configuration;
033
034    private final OneShotLock lock = new OneShotLock();
035
036    public RegistryStartup(Logger logger, final List<Runnable> configuration)
037    {
038        this.logger = logger;
039        this.configuration = configuration;
040    }
041
042    /**
043     * Invokes run() on each contributed object. If the object throws a runtime exception, it is logged but startup
044     * continues anyway. This method may only be {@linkplain OneShotLock invoked once}.
045     */
046    @Override
047    public void run()
048    {
049        lock.lock();
050
051        // Do we want extra exception catching here?
052
053        for (Runnable r : configuration)
054        {
055            try
056            {
057                r.run();
058            } catch (RuntimeException ex)
059            {
060                // startup-failure=An exception occurred during startup: %s
061
062                logger.error(String.format("An exception occurred during startup: %s",
063                        ExceptionUtils.toMessage(ex)), ex);
064            }
065        }
066
067        // We don't need them any more since this method can only be run once. It's a insignificant
068        // savings, but still a nice thing to do.
069
070        configuration.clear();
071    }
072
073}