bmstatement.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.sail.test.benchmark.model;

import java.io.Serializable;

import org.openrdf.model.Resource;
import org.openrdf.model.URI;
import org.openrdf.model.Value;

/**
 * Represents a statement used by benchmark test. Test uses a slightly different
 * statement than Sesame does, e.g. its subject, predicate and object may be null
 * to indicate wildcards.
 *
 * @author Peter van 't Hof
 * @version %I%, %G%
 */
public class BMStatement implements Serializable {

/*----------+
| Variables |
+----------*/
	protected Resource _subject;
	protected URI _predicate;
	protected Value _object;

/*-------------+
| Constructors |
+-------------*/
	/**
	 * Creates a new BMStatement.
	 *
	 * @param subject Subject of statement, may be null to indicate a wildcard.
	 * @param predicate Predicate of statement, may be null to indicate a
	 * wildcard.
	 * @param object Object of statement, may be null to indicate a wildcard.
	 */
	public BMStatement(Resource subject, URI predicate, Value object) {
		_subject = subject;
		_predicate = predicate;
		_object = object;
	}

/*--------+
| Methods |
+--------*/	
	/**
	 * Gets subject of statement.
	 *
	 * @return Subject of statement.
	 */
	public Resource getSubject() {
		return _subject;
	}

	/**
	 * Gets predicate of statement.
	 *
	 * @return Predicate of statement.
	 */
	public URI getPredicate() {
		return _predicate;
	}

	/**
	 * Gets object of statement.
	 *
	 * @return Object of statement.
	 */
	public Value getObject() {
		return _object;
	}

	/**
	 * Indicates whether some other object is equal to this one.
	 *
	 * @return True if this object is the same as the obj argument; false
	 * otherwise.
	 */
	public boolean equals(Object other) {
		if (this == other) {
			return true;
		}
		else {
			if (other instanceof BMStatement) {
				BMStatement bmStatement = (BMStatement)other;
				
				return _equals(_subject, bmStatement.getSubject()) && 
					_equals(_predicate, bmStatement.getPredicate()) && 
					_equals(_object, bmStatement.getObject());
			}
		}

		return false;
	}

	/* Equals two Values. Both may be null to indicate wildcards. If both are
	 * wildcards, they are equal. If one of them is a wildcard they are not.
	 */
	protected boolean _equals(Value value1, Value value2) {
		if (value1 == null && value2 != null || value1 != null && value2 == null) {
			return false;
		}
		else {
			if (value1 == null && value2 == null) {
				return true;
			}
			else {
				return value1.equals(value2);
			}
		}
	}

	/**
	 * Returns hashcode of BMStatement.
	 *
	 * @return Hashcode of BMStatement.
	 */
	public int hashCode() {
		int hashCode = 0;

		if (_subject != null) {
			hashCode |= _subject.hashCode() & 0xFF0000;
		}
		if (_predicate != null) {
			hashCode |= _predicate.hashCode() & 0x00FF00;
		}
		if (_object != null) {
			hashCode |= _object.hashCode() & 0x0000FF;
		}

 		return hashCode;
 	}

	/**
	 * Returns String representation of BMStatement.
	 *
	 * @return String representation of BMStatement.
	 */
	public String toString() {
		String toString = "";

		if (_subject == null) {
			toString += "*";
		}
		else {
			toString += _subject.toString();
		}

		toString += ", ";

		if (_predicate == null) {
			toString += "*";
		}
		else {
			toString += _predicate.toString();
		}

		toString += ", ";

		if (_object == null) {
			toString += "*";
		}
		else {
			toString += _object.toString();
		}

		return toString;
	}
}