rdbmsnamespaceiterator.java

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/*  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.rdbms.iterators;

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

import org.openrdf.sesame.sail.NamespaceIterator;
import org.openrdf.sesame.sailimpl.rdbms.RdbmsNamespace;

/**
 * A NamespaceIterator that returns namespaces from a cache.
 *
 * @author Peter van 't Hof
 * @author Arjohn Kampman
 * @version $Revision: 1.4 $
 */
public class RdbmsNamespaceIterator implements NamespaceIterator {

/*----------+
| Variables |
+----------*/

	/** Namespace. */
	protected RdbmsNamespace _namespace;

	/** Iterator over cache. */
	protected Iterator _iterator;

/*-------------+
| Constructors |
+-------------*/
	/**
	 * Constructor.
	 *
	 * @param namespaces cache from which namespaces are returned
	 */
	public RdbmsNamespaceIterator(List namespaces) {
		// Copy namespace objects to prevent Exception from being thrown
		// because of changes in the namespaces Map:
		ArrayList namespaceList = new ArrayList();
		Iterator it = namespaces.iterator();

		// only put exported namespaces in the iterator
		while (it.hasNext()) {
			RdbmsNamespace ns = (RdbmsNamespace)it.next();
			if (ns.exported()) {
				namespaceList.add(ns);
			}
		}
		it = null;
		_iterator = namespaceList.iterator();
	}

/*--------+
| Methods |
+--------*/

	public boolean hasNext() {
		return _iterator.hasNext();
	}

	public void next() {
		_namespace = (RdbmsNamespace)_iterator.next();
	}

	public String getPrefix() {
		return _namespace.getPrefix();
	}

	public String getName() {
		return _namespace.getName();
	}

	public void close() {
		_iterator = null;
	}
}