graphstatisticshandler.java

jena2.5.4推理机系统的一种最基本实现 HP实验室出品

/*
 	(c) Copyright 2007 Hewlett-Packard Development Company, LP
 	All rights reserved.
 	$Id: GraphStatisticsHandler.java,v 1.2 2007/07/19 13:26:50 chris-dollin Exp $
*/

package com.hp.hpl.jena.graph;

/**
    A graph's StatisticsHandler offers access to some statistics about that
    graph's contents that might be useful for optimisation.
    
 	@author kers
*/
public interface GraphStatisticsHandler
    {
    /**
        Answer a good estimate of the number of triples that would match the
        pattern <code>(S, P, O)</code>, or -1 if no good estimate is available.
        The estimate is good until the graph is updated.
    */
    public long getStatistic( Node S, Node P, Node O );
    }


/*
 * (c) Copyright 2005, 2006, 2007 Hewlett-Packard Development Company, LP
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/