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.graph.cache;
023    
024    import java.io.Serializable;
025    import net.jcip.annotations.Immutable;
026    
027    /**
028     * The specification of how node data is to be cached. The time values provided are relative, allowing the same cache policy
029     * instance to be shared among multiple {@link Cacheable} objects.
030     * 
031     * @author Randall Hauch
032     */
033    @Immutable
034    public interface CachePolicy extends Serializable {
035    
036        /**
037         * Get the system time in milliseconds before which the node data remains valid.
038         * 
039         * @return the number of milliseconds that the cached data should be used before consulting the original source.
040         */
041        public long getTimeToLive();
042    
043    }