fblprulereasoner.java

jena2.5.4推理机系统的一种最基本实现 HP实验室出品

/******************************************************************
 * File:        FBLPRuleReasoner.java
 * Created by:  Dave Reynolds
 * Created on:  26-Jul-2003
 * 
 * (c) Copyright 2003, 2004, 2005, 2006, 2007 Hewlett-Packard Development Company, LP
 * [See end of file]
 * $Id: FBLPRuleReasoner.java,v 1.10 2007/01/02 11:52:33 andy_seaborne Exp $
 *****************************************************************/
package com.hp.hpl.jena.reasoner.rulesys.impl.oldCode;


import com.hp.hpl.jena.rdf.model.*;
import com.hp.hpl.jena.reasoner.*;
import com.hp.hpl.jena.reasoner.rulesys.ClauseEntry;
import com.hp.hpl.jena.reasoner.rulesys.Functor;
import com.hp.hpl.jena.reasoner.rulesys.Rule;
import com.hp.hpl.jena.reasoner.rulesys.Util;
import com.hp.hpl.jena.vocabulary.ReasonerVocabulary;
import com.hp.hpl.jena.graph.*;

import java.util.*;

/**
 * Rule-based reasoner interface. This is the default rule reasoner to use.
 * It supports both forward reasoning and backward reasoning, including use
 * of forward rules to generate and instantiate backward rules.
 * 
 * This version is purely temporary during development of the LP engine and will get
 * replaced by the upgraded FBRuleReasoner when the LP section is released.
 * 
 * @author <a href="mailto:[e-mail]">Dave Reynolds</a>
 * @version $Revision: 1.10 $ on $Date: 2007/01/02 11:52:33 $
 */
public class FBLPRuleReasoner implements Reasoner {
    
    /** The parent reasoner factory which is consulted to answer capability questions */
    protected ReasonerFactory factory;

    /** The rules to be used by this instance of the forward engine */
    protected List rules;
    
    /** A precomputed set of schema deductions */
    protected Graph schemaGraph;
    
    /** Flag to set whether the inference class should record derivations */
    protected boolean recordDerivations = false;

    /** Flag which, if true, enables tracing of rule actions to logger.info */
    protected boolean traceOn = false;

    /** Flag, if true we cache the closure of the pure rule set with its axioms */
    protected static final boolean cachePreload = true;
    
    /** The cached empty closure, if wanted */
    protected InfGraph preload;  
    
    /** The graph capabilities of the infgraphs generated by this reasoner */
    protected Capabilities capabilities;
     
    /**
     * Constructor. This is the raw version that does not reference a ReasonerFactory
     * and so has no capabilities description. 
     * @param rules a list of Rule instances which defines the ruleset to process
     */
    public FBLPRuleReasoner(List rules) {
        this.rules = rules;
    }
    
    /**
     * Constructor
     * @param factory the parent reasoner factory which is consulted to answer capability questions
     */
    public FBLPRuleReasoner(ReasonerFactory factory) {
        this(null, factory);
    }
    
    /**
     * Constructor
     * @param rules a list of Rule instances which defines the ruleset to process
     * @param factory the parent reasoner factory which is consulted to answer capability questions
     */
    public FBLPRuleReasoner(List rules, ReasonerFactory factory) {
        this(rules);
        this.factory = factory;
    }
    
    /**
     * Internal constructor, used to generated a partial binding of a schema
     * to a rule reasoner instance.
     */
    protected FBLPRuleReasoner(List rules, Graph schemaGraph, ReasonerFactory factory) {
        this(rules, factory);
        this.schemaGraph = schemaGraph;
    }

    /**
     * Return a description of the capabilities of this reasoner encoded in
     * RDF. These capabilities may be static or may depend on configuration
     * information supplied at construction time. May be null if there are
     * no useful capabilities registered.
     */
    public Model getReasonerCapabilities() {
        if (factory != null) {
            return factory.getCapabilities();
        } else {
            return null;
        }
    }
    
    /**
     * Add a configuration description for this reasoner into a partial
     * configuration specification model.
     * @param configSpec a Model into which the configuration information should be placed
     * @param base the Resource to which the configuration parameters should be added.
     */
    public void addDescription(Model configSpec, Resource base) {
        // No configuration
    }

    /**
     * Determine whether the given property is recognized and treated specially
     * by this reasoner. This is a convenience packaging of a special case of getCapabilities.
     * @param property the property which we want to ask the reasoner about, given as a Node since
     * this is part of the SPI rather than API
     * @return true if the given property is handled specially by the reasoner.
     */
    public boolean supportsProperty(Property property) {
        if (factory == null) return false;
        Model caps = factory.getCapabilities();
        Resource root = caps.getResource(factory.getURI());
        return caps.contains(root, ReasonerVocabulary.supportsP, property);
    }
    
    /**
     * Precompute the implications of a schema graph. The statements in the graph
     * will be combined with the data when the final InfGraph is created.
     */
    public Reasoner bindSchema(Graph tbox) throws ReasonerException {
        if (schemaGraph != null) {
            throw new ReasonerException("Can only bind one schema at a time to an OWLRuleReasoner");
        }
        FBLPRuleInfGraph graph = new FBLPRuleInfGraph(this, rules, getPreload(), tbox);
        graph.prepare();
        FBLPRuleReasoner fbr  = new FBLPRuleReasoner(rules, graph, factory);
        fbr.setDerivationLogging(recordDerivations);
        fbr.setTraceOn(traceOn);
        return fbr;
    }
    
    /**
     * Precompute the implications of a schema Model. The statements in the graph
     * will be combined with the data when the final InfGraph is created.
     */
    public Reasoner bindSchema(Model tbox) throws ReasonerException {
        return bindSchema(tbox.getGraph());
    }
    
    /**
     * Attach the reasoner to a set of RDF data to process.
     * The reasoner may already have been bound to specific rules or ontology
     * axioms (encoded in RDF) through earlier bindRuleset calls.
     * 
     * @param data the RDF data to be processed, some reasoners may restrict
     * the range of RDF which is legal here (e.g. syntactic restrictions in OWL).
     * @return an inference graph through which the data+reasoner can be queried.
     * @throws ReasonerException if the data is ill-formed according to the
     * constraints imposed by this reasoner.
     */
    public InfGraph bind(Graph data) throws ReasonerException {
        Graph schemaArg = schemaGraph == null ? getPreload() : (FBLPRuleInfGraph)schemaGraph; 
        FBLPRuleInfGraph graph = new FBLPRuleInfGraph(this, rules, schemaArg);
        graph.setDerivationLogging(recordDerivations);
        graph.setTraceOn(traceOn);
        graph.rebind(data);
        return graph;
    }
    
    /**
     * Set (or change) the rule set that this reasoner should execute.
     * @param rules a list of Rule objects
     */
    public void setRules(List rules) {
        this.rules = rules;
        preload = null;
    }
    
    /**
     * Return the this of Rules used by this reasoner
     * @return a List of Rule objects
     */
    public List getRules() {
        return rules;
    } 
    
    /**
     * Register an RDF predicate as one whose presence in a goal should force
     * the goal to be tabled. This is better done directly in the rule set.
     */
    public synchronized void tablePredicate(Node predicate) {
        // Create a dummy rule which tables the predicate ...
        Rule tablePredicateRule = new Rule("", 
                new ClauseEntry[]{
                    new Functor("table", new Node[] { predicate })
                }, 
                new ClauseEntry[]{});
        // ... end append the rule to the ruleset
        rules.add(tablePredicateRule);
    }
    
    /**
     * Get the single static precomputed rule closure.
     */
    protected synchronized InfGraph getPreload() {
        if (cachePreload && preload == null) {
            preload = (new FBLPRuleInfGraph(this, rules, null));
            preload.prepare();
        }
        return preload;
    }
       
    /**
     * Switch on/off drivation logging.
     * If set to true then the InfGraph created from the bind operation will start
     * life with recording of derivations switched on. This is currently only of relevance
     * to rule-based reasoners.
     * <p>
     * Default - false.
     */
    public void setDerivationLogging(boolean logOn) {
        recordDerivations = logOn;
    }
    
    /**
     * Set the state of the trace flag. If set to true then rule firings
     * are logged out to the Log at "INFO" level.
     */
    public void setTraceOn(boolean state) {
        traceOn = state;
    }
    
    /**
     * Set a configuration paramter for the reasoner. The supported parameters
     * are:
     * <ul>
     * <li>PROPderivationLogging - set to true to enable recording all rule derivations</li>
     * <li>PROPtraceOn - set to true to enable verbose trace information to be sent to the logger INFO channel</li>
     * </ul> 
     * 
     * @param parameterUri the property identifying the parameter to be changed
     * @param value the new value for the parameter, typically this is a wrapped
     * java object like Boolean or Integer.
     */
    public void setParameter(Property parameter, Object value) {
        if (parameter.equals(ReasonerVocabulary.PROPderivationLogging)) {
            recordDerivations = Util.convertBooleanPredicateArg(parameter, value);
        } else if (parameter.equals(ReasonerVocabulary.PROPtraceOn)) {
            traceOn =  Util.convertBooleanPredicateArg(parameter, value);
        } else {
            throw new IllegalParameterException("Don't recognize configuration parameter " + parameter + " for rule-based reasoner");
        }
    }

    /**
     * Return the Jena Graph Capabilties that the inference graphs generated
     * by this reasoner are expected to conform to.
     */
    public Capabilities getGraphCapabilities() {
        if (capabilities == null) {
            capabilities = new BaseInfGraph.InfCapabilities();
        }
        return capabilities;
    }

}



/*
    (c) Copyright 2003, 2004, 2005, 2006, 2007 Hewlett-Packard Development Company, LP
    All rights reserved.

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    modification, are permitted provided that the following conditions
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    3. The name of the author may not be used to endorse or promote products
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    THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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