001    /*
002     * JBoss, Home of Professional Open Source.
003     * Copyright 2008, Red Hat Middleware LLC, and individual contributors
004     * as indicated by the @author tags. See the copyright.txt file in the
005     * distribution for a full listing of individual contributors. 
006     *
007     * This is free software; you can redistribute it and/or modify it
008     * under the terms of the GNU Lesser General Public License as
009     * published by the Free Software Foundation; either version 2.1 of
010     * the License, or (at your option) any later version.
011     *
012     * This software is distributed in the hope that it will be useful,
013     * but WITHOUT ANY WARRANTY; without even the implied warranty of
014     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015     * Lesser General Public License for more details.
016     *
017     * You should have received a copy of the GNU Lesser General Public
018     * License along with this software; if not, write to the Free
019     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
021     */
022    package org.jboss.dna.connector.federation.contribution;
023    
024    import java.util.Iterator;
025    import net.jcip.annotations.Immutable;
026    import org.jboss.dna.graph.properties.DateTime;
027    import org.jboss.dna.graph.properties.Path;
028    import org.jboss.dna.graph.properties.Path.Segment;
029    
030    /**
031     * The record of a source contributing only two children to a node.
032     * 
033     * @author Randall Hauch
034     */
035    @Immutable
036    public class TwoChildContribution extends NonEmptyContribution {
037    
038        /**
039         * This is the first version of this class. See the documentation of MergePlan.serialVersionUID.
040         */
041        private static final long serialVersionUID = 1L;
042    
043        private final Segment child1;
044        private final Segment child2;
045    
046        /**
047         * Create a contribution of two children from the source with the supplied name.
048         * 
049         * @param sourceName the name of the source, which may not be null or blank
050         * @param pathInSource the path in the source for this contributed information; may not be null
051         * @param expirationTime the time (in UTC) after which this contribution should be considered expired, or null if there is no
052         *        expiration time
053         * @param child1 the first child contributed from the source; may not be null
054         * @param child2 the second child contributed from the source; may not be null
055         */
056        public TwoChildContribution( String sourceName,
057                                     Path pathInSource,
058                                     DateTime expirationTime,
059                                     Segment child1,
060                                     Segment child2 ) {
061            super(sourceName, pathInSource, expirationTime);
062            assert child1 != null;
063            assert child2 != null;
064            this.child1 = child1;
065            this.child2 = child2;
066            if (ContributionStatistics.RECORD) ContributionStatistics.record(0, 2);
067        }
068    
069        /**
070         * {@inheritDoc}
071         * 
072         * @see org.jboss.dna.connector.federation.contribution.Contribution#getChildren()
073         */
074        @Override
075        public Iterator<Segment> getChildren() {
076            return new TwoValueIterator<Segment>(child1, child2);
077        }
078    
079        /**
080         * {@inheritDoc}
081         * 
082         * @see org.jboss.dna.connector.federation.contribution.Contribution#getChildrenCount()
083         */
084        @Override
085        public int getChildrenCount() {
086            return 2;
087        }
088    
089    }