urinode.java

这是外国一个开源推理机

/*  Sesame - Storage and Querying architecture for RDF and RDF Schema
 *  Copyright (C) 2001-2005 Aduna
 *
 *  Contact:
 *  	Aduna
 *  	Prinses Julianaplein 14 b
 *  	3817 CS Amersfoort
 *  	The Netherlands
 *  	tel. [phone]
 *  	fax. [phone]
 *
 *  	http://aduna.biz/
 *  	http://www.openrdf.org/
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package org.openrdf.sesame.sailimpl.memory;

import java.util.ArrayList;
import java.util.List;

import org.openrdf.model.GraphException;
import org.openrdf.model.Resource;
import org.openrdf.model.Statement;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import org.openrdf.model.impl.URIImpl;

import org.openrdf.sesame.sail.SailUpdateException;
import org.openrdf.sesame.sail.StatementIterator;
import org.openrdf.sesame.sail.util.EmptyStatementIterator;

/**
 * An extension of URI giving it node properties.
 *
 * @author Arjohn Kampman
 * @version $Revision: 1.15 $
 **/
public class URINode extends URIImpl implements ResourceNode {
	
/*---------------+
| Variables      |
+---------------*/
	
	transient protected RdfSource _source;
	
	/** The list of statements for which this URINode is the subject. **/
	transient protected StatementList _subjectStatements;
	
	/** The list of statements for which this URINode is the predicate. **/
	transient protected StatementList _predicateStatements;
	
	/** The list of statements for which this URINode is the object. **/
	transient protected StatementList _objectStatements;
	
	transient protected StatementList _directTypeStatements;
	
	transient protected StatementList _directSubClassStatements;
	
	transient protected StatementList _directSubPropertyStatements;
	
/*---------------+
| Constructors   |
+---------------*/
	
	/**
	 * Creates a new URINode for a URI.
	 *
	 * @param source The Sail instance that created this URINode.
	 * @param namespace namespace part of URI
	 * @param localName localname part of URI
	 */
	URINode(RdfSource source, String namespace, String localName) {
		super(namespace, localName);
		_source = source;
	}
	
	URINode(RdfSource source, String uri) {
		super(uri);
		_source = source;
	}
	
/*-----------------------------------+
| Methods for _subjectStatements     |
+-----------------------------------*/

	public StatementList getSubjectStatementList() {
		if (_subjectStatements == null) {
			return EMPTY_LIST;
		}
		else {
			return _subjectStatements;
		}
	}
	
	/**
	 * Gets the list of Statements for which this URINode is the subject.
	 * @return A List of Statements.
	 **/
	public StatementIterator getSubjectStatements() {
		if (_subjectStatements == null) {
			return new EmptyStatementIterator();
		}
		else {
			return new MemStatementIterator(_subjectStatements);
		}
	}
	
	/**
	 * Gets the amount of Statements for which this URINode is the subject.
	 * @return An integer larger than or equal to 0.
	 **/
	public int getSubjectStatementCount() {
		if (_subjectStatements == null) {
			return 0;
		}
		else {
			return _subjectStatements.size();
		}
	}
	
	/**
	 * Adds a statement to this URINode's list of statements for which
	 * it is the subject.
	 **/
	public void addSubjectStatement(Statement st) {
		if (_subjectStatements == null) {
			_subjectStatements = new StatementList(4);
		}
		_subjectStatements.add(st);
	}
	
	/**
	 * Removes a statement from this URINode's list of statements for which
	 * it is the subject.
	 **/
	public void removeSubjectStatement(Statement st) {
		_subjectStatements.remove(st);
		if (_subjectStatements.isEmpty()) {
			_subjectStatements = null;
		}
	}
	
/*-----------------------------------+
| Methods for _predicateStatements   |
+-----------------------------------*/

	public StatementList getPredicateStatementList() {
		if (_predicateStatements == null) {
			return EMPTY_LIST;
		}
		else {
			return _predicateStatements;
		}
	}
	
	/**
	 * Gets the list of Statements for which this URINode is the predicate.
	 * @return A List of Statements.
	 **/
	public StatementIterator getPredicateStatements() {
		if (_predicateStatements == null) {
			return new EmptyStatementIterator();
		}
		else {
			return new MemStatementIterator(_predicateStatements);
		}
	}
	
	/**
	 * Gets the amount of Statements for which this URINode is the predicate.
	 * @return An integer larger than or equal to 0.
	 **/
	public int getPredicateStatementCount() {
		if (_predicateStatements == null) {
			return 0;
		}
		else {
			return _predicateStatements.size();
		}
	}
	
	/**
	 * Adds a statement to this URINode's list of statements for which
	 * it is the predicate.
	 **/
	public void addPredicateStatement(Statement st) {
		if (_predicateStatements == null) {
			_predicateStatements = new StatementList(4);
		}
		_predicateStatements.add(st);
	}
	
	/**
	 * Removes a statement from this URINode's list of statements for which
	 * it is the predicate.
	 **/
	public void removePredicateStatement(Statement st) {
		_predicateStatements.remove(st);
		if (_predicateStatements.isEmpty()) {
			_predicateStatements = null;
		}
	}
	
/*-----------------------------------+
| Methods for _objectStatements      |
+-----------------------------------*/

	public StatementList getObjectStatementList() {
		if (_objectStatements == null) {
			return EMPTY_LIST;
		}
		else {
			return _objectStatements;
		}
	}
	
	/**
	 * Gets the list of Statements for which this URINode is the object.
	 * @return A List of Statements, or null if no such statement exists.
	 **/
	public StatementIterator getObjectStatements() {
		if (_objectStatements == null) {
			return new EmptyStatementIterator();
		}
		else {
			return new MemStatementIterator(_objectStatements);
		}
	}
	
	/**
	 * Gets the amount of Statements for which this URINode is the object.
	 * @return An integer larger than or equal to 0.
	 **/
	public int getObjectStatementCount() {
		if (_objectStatements == null) {
			return 0;
		}
		else {
			return _objectStatements.size();
		}
	}
	
	/**
	 * Adds a statement to this URINode's list of statements for which
	 * it is the object.
	 **/
	public void addObjectStatement(Statement st) {
		if (_objectStatements == null) {
			_objectStatements = new StatementList(4);
		}
		_objectStatements.add(st);
	}
	
	/**
	 * Removes a statement from this URINode's list of statements for which
	 * it is the object.
	 **/
	public void removeObjectStatement(Statement st) {
		_objectStatements.remove(st);
		if (_objectStatements.isEmpty()) {
			_objectStatements = null;
		}
	}
	
	public RdfSource getRdfSource() {
		return _source;
	}
	
	
	public void addProperty(URI property, Value value)
		throws GraphException
	{
		if (_source instanceof RdfRepository) {
			RdfRepository rep = (RdfRepository)_source;
			rep.startTransaction();
			try {
				rep.addStatement(this, property, value);
			}
			catch (SailUpdateException e) {
				throw new GraphException(e);
			}
			finally {
				rep.commitTransaction();