connect/src/main/java/org/apache/felix/connect/EntriesEnumeration.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.felix.connect;

import java.util.Enumeration;
import java.util.zip.ZipEntry;

class EntriesEnumeration implements Enumeration
{
    private final Enumeration m_enumeration;
	private final String m_prefix;
	private volatile Object current;

    public EntriesEnumeration(Enumeration enumeration)
    {
        this(enumeration, null);
    }
	
	public EntriesEnumeration(Enumeration enumeration, String prefix)
	{
	   m_enumeration = enumeration;
	   m_prefix = prefix;
	}

    public boolean hasMoreElements() {
				while ((current == null) && m_enumeration.hasMoreElements()) {
					String result = (String) ((ZipEntry) m_enumeration.nextElement()).getName();
					if (m_prefix != null){
						if (result.startsWith(m_prefix)) {
							current = result.substring(m_prefix.length());
						}
					}
					else {
						current = result;
					}
				}
				return (current != null);
			}

			public Object nextElement() {
				try {
					if (hasMoreElements()) {
						return current;
					}
					else {
						return m_enumeration.nextElement();
					}
				} finally { 
					current = null;
				}
			}
}