001/*
002 * #%L
003 * Netarchivesuite - common
004 * %%
005 * Copyright (C) 2005 - 2014 The Royal Danish Library, the Danish State and University Library,
006 *             the National Library of France and the Austrian National Library.
007 * %%
008 * This program is free software: you can redistribute it and/or modify
009 * it under the terms of the GNU Lesser General Public License as
010 * published by the Free Software Foundation, either version 2.1 of the
011 * License, or (at your option) any later version.
012 * 
013 * This program is distributed in the hope that it will be useful,
014 * but WITHOUT ANY WARRANTY; without even the implied warranty of
015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016 * GNU General Lesser Public License for more details.
017 * 
018 * You should have received a copy of the GNU General Lesser Public
019 * License along with this program.  If not, see
020 * <http://www.gnu.org/licenses/lgpl-2.1.html>.
021 * #L%
022 */
023package dk.netarkivet.common.lifecycle;
024
025import java.util.ArrayList;
026import java.util.List;
027
028import org.slf4j.Logger;
029import org.slf4j.LoggerFactory;
030
031import dk.netarkivet.common.exceptions.ArgumentNotValid;
032
033/**
034 * Takes care of the lifecycling of subcomponents(children).
035 * <p>
036 * When extending this class you must:
037 * <ol>
038 * <li>Add all lifecycle subcomponents with the addChild, before the start method is called.
039 * <li>Call the <code>super.start()</code> operation to start the children.
040 * <li>Call the <code>super.shutdown</code> operation to
041 */
042public class LifeCycleComponent implements ComponentLifeCycle {
043
044    /** The instance logger. */
045    private static final Logger log = LoggerFactory.getLogger(LifeCycleComponent.class);
046
047    /** The child-components of this lifecycle. */
048    private List<ComponentLifeCycle> children = new ArrayList<ComponentLifeCycle>();
049
050    @Override
051    public void start() {
052        log.debug("Starting {}", toString());
053        for (ComponentLifeCycle child : children) {
054            child.start();
055        }
056    }
057
058    @Override
059    public void shutdown() {
060        log.debug("Shutting down {}", toString());
061        for (ComponentLifeCycle child : children) {
062            child.shutdown();
063        }
064    }
065
066    /**
067     * Adds a child <code>ComponentLifeCycle</code>. The childs lifecycle will be managed by by the
068     * <code>LifeCycleComponent</code>.
069     *
070     * @param childComponent The child to add
071     */
072    public void addChild(ComponentLifeCycle childComponent) {
073        ArgumentNotValid.checkNotNull(childComponent, "Child can not be null");
074        children.add(childComponent);
075    }
076
077}