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 net.jcip.annotations.Immutable; 025 import org.jboss.dna.graph.Location; 026 import org.jboss.dna.graph.properties.DateTime; 027 028 /** 029 * A source contribution that is empty. In other words, the source has no contribution to make. 030 * <p> 031 * Note that this is different than an unknown contribution, which may occur when a source is added to a federated repository 032 * after the contributions have already been determined for nodes. In this case, the new source's contribution for a node is not 033 * known and must be determined. 034 * </p> 035 * 036 * @author Randall Hauch 037 */ 038 @Immutable 039 public class EmptyContribution extends Contribution { 040 041 /** 042 * This is the first version of this class. See the documentation of MergePlan.serialVersionUID. 043 */ 044 private static final long serialVersionUID = 1L; 045 046 /** 047 * Create a contribution for the source with the supplied name. 048 * 049 * @param sourceName the name of the source, which may not be null or blank 050 * @param expirationTime the time (in UTC) after which this contribution should be considered expired, or null if there is no 051 * expiration time 052 */ 053 public EmptyContribution( String sourceName, 054 DateTime expirationTime ) { 055 super(sourceName, expirationTime); 056 if (ContributionStatistics.RECORD) ContributionStatistics.record(0, 0); 057 } 058 059 /** 060 * {@inheritDoc} 061 * 062 * @see org.jboss.dna.connector.federation.contribution.Contribution#getLocationInSource() 063 */ 064 @Override 065 public Location getLocationInSource() { 066 return null; 067 } 068 069 /** 070 * {@inheritDoc} 071 * 072 * @see org.jboss.dna.connector.federation.contribution.Contribution#isEmpty() 073 */ 074 @Override 075 public boolean isEmpty() { 076 return true; 077 } 078 079 /** 080 * {@inheritDoc} 081 */ 082 @Override 083 public boolean equals( Object obj ) { 084 if (obj == this) return true; 085 if (obj instanceof EmptyContribution) { 086 EmptyContribution that = (EmptyContribution)obj; 087 if (!this.getSourceName().equals(that.getSourceName())) return false; 088 return true; 089 } 090 return false; 091 } 092 }