/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.core.util;

import java.util.Enumeration;

/**
 * The <code>ICacheEnumeration</code> is used to iterate over both the keys
 * and values in an LRUCache. The <code>getValue()</code> method returns the
 * value of the last key to be retrieved using <code>nextElement()</code>.
 * The <code>nextElement()</code> method must be called before the
 * <code>getValue()</code> method.
 * 
 * <p>
 * The iteration can be made efficient by making use of the fact that values in
 * the cache (instances of <code>LRUCacheEntry</code>), know their key. For
 * this reason, Hashtable lookups don't have to be made at each step of the
 * iteration.
 * 
 * <p>
 * Modifications to the cache must not be performed while using the enumeration.
 * Doing so will lead to an illegal state.
 * 
 * @see LRUCache
 */
public interface ICacheEnumeration extends Enumeration {
	/**
	 * Returns the value of the previously accessed key in the enumeration. Must
	 * be called after a call to nextElement().
	 * 
	 * @return Value of current cache entry
	 */
	public Object getValue();
}
