reifiedstatementimpl.java

Jena推理机

/*
	(c) Copyright 2003, 2004, 2005, 2006, 2007 Hewlett-Packard Development Company, LP
	[see end of file]
	$Id: ReifiedStatementImpl.java,v 1.12 2007/01/02 11:48:30 andy_seaborne Exp $
*/

package com.hp.hpl.jena.rdf.model.impl;

import com.hp.hpl.jena.enhanced.*;
import com.hp.hpl.jena.graph.*;
import com.hp.hpl.jena.rdf.model.*;


/**
    A ReifiedStatementImpl encodes a Statement and behaves as a Resource.
*/

public class ReifiedStatementImpl extends ResourceImpl implements ReifiedStatement
    {
    /** the Statement that this ReifiedStatement represents */
    protected Statement statement;
    
    /**
        private constructor, relies (ugh) on super(uri, model) generating
        bnode if uril == null. 
    */

    private ReifiedStatementImpl( ModelCom m, String uri, Statement s ) 
        {
        super( uri, m ); 
        assertStatement( s ); 
        }
        
    protected ReifiedStatementImpl( EnhGraph m, Node n, Statement s )
        {
        super( n, m );
        assertStatement( s );
        }
        
    private void assertStatement( Statement s )
        {
        statement = s;
        }
        
    /** 
        answer [a .equals() version of] the Statement that this ReifiedStatement
        represents.
    */
    public Statement getStatement() 
        { return statement; }
       
    static final public Implementation reifiedStatementFactory = new Implementation() 
        {
        /**
            convert a _node_ into a ReifiedStatement in the enhanced graph 
            _eg_ by looking into this graph's reifier to find the binding for the
            node; throw a DoesNotReify exception if there's no mapping. 
        */
        public EnhNode wrap( Node n, EnhGraph eg ) 
            {
            Triple x = getTriple( eg, n );
            if (x == null) throw new DoesNotReifyException( n );
            Statement st = StatementImpl.toStatement( x, (ModelCom) eg );
            return new ReifiedStatementImpl( eg, n, st );
            }

        /**
            Answer true iff the node <code>n</code> can become a reified statement,
            ie it is associated with a triple by <code>eg</code>'s Reifier.
            @param eg the (enhanced) graph who's Reifier might hold the triple
            @param n the node who's triple is required
            @return true iff there's an associated triple
        */
        public boolean canWrap( Node n, EnhGraph eg )
            { return getTriple( eg, n ) != null; }
            
        /**
            Answer the triple associated with <code>n</code> by eg's graph's Reifier.
            @param eg the (enhanced) graph who's Reifier might hold the triple
            @param n the node who's triple is required
            @return the associated triple if any, otherwise null
        */
        private Triple getTriple( EnhGraph eg, Node n )
            { return eg.asGraph().getReifier().getTriple( n ); }
        };
        
    /**
        Answer our Reifier (ie our Model's Graph's Reifier).
    */
    protected Reifier getReifier()
        { return getModel().getGraph().getReifier(); }
        
    public boolean isValid()
        { return getModel().getGraph().getReifier().getTriple( this.asNode() ) != null; }
        
    /**
        tell the underlying graph's reifier that this ReifiedStatement's node
        represents any Statement with this statement's triple. (May throw an
        exception if the node is already reified to something different.)
    */        
    private ReifiedStatementImpl installInReifier()
        {
        getReifier().reifyAs( this.asNode(), statement.asTriple() );
        return this;
        }
      
    /**
        factory method. answer a ReifiedStatement which encodes the
        Statement _s_. The mapping is remembered.
    */  
    public static ReifiedStatement create( Statement s )
        { return create( (ModelCom) s.getModel(), (String) null, s ); }

    /**
        factory method. answer a ReifiedStatement which encodes the
        Statement _s_ with uri _uri_. The mapping is remembered.
    */        
    public static ReifiedStatementImpl create( ModelCom m, String uri, Statement s )
        { return new ReifiedStatementImpl( m, uri, s ).installInReifier(); }        
        
    public static ReifiedStatementImpl create( EnhGraph eg, Node n, Statement s )
        { return new ReifiedStatementImpl( eg, n, s ).installInReifier(); }
    
    public String toString()
        { return super.toString() + "=>" + statement; }

    public static ReifiedStatement createExistingReifiedStatement( ModelCom model, Node n )
        {
        Triple t = model.getGraph().getReifier().getTriple( n );
        return new ReifiedStatementImpl( model, n, model.asStatement( t ) );
        }
    }
    
/*
    (c) Copyright 2003, 2004, 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.
*/