mq5.0-source.main.mq-broker.broker-core.src.main.java.com.sun.messaging.jmq.jmsserver.persist.api.util.DataEnumeration Maven / Gradle / Ivy

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2000-2012 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

/*
 * @(#)DataEnumeration.java	1.3 06/29/07
 */ 

package com.sun.messaging.jmq.jmsserver.persist.api.util;

import com.sun.messaging.jmq.jmsserver.util.BrokerException;
import java.util.*;

/**
 * DataEnumeration represent an enumeration of some types of data.
 */
public class DataEnumeration implements Enumeration {

    private EnumerationStore store;
    private Object[] ids;
    private int index = 0;
    private Object next = null;

    public DataEnumeration(EnumerationStore store, Object[] ids) {
	if (ids == null)
	    ids = new Object[0];

	this.store = store;
	this.ids = ids;
    }

    public boolean hasMoreElements() {
	if (index >= ids.length)
	    return false;

	for (; index < ids.length && next == null; index++) {
	    try {
		next = store.getData(ids[index]);
	    } catch (BrokerException e) {
		// get as much as we can
		next = null;
	    }
	}

	if (next != null)
	    return true;
	else
	    return false;
    }

    public Object nextElement() {
	Object data = next;
	if (data != null) {
	    next = null;
	    return data;
	} else {
	    throw new NoSuchElementException();
	}
    }
}