/*******************************************************************************
 * 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;

import net.sourceforge.phpdt.core.IOpenable;
import net.sourceforge.phpdt.core.JavaModelException;
import net.sourceforge.phpdt.internal.core.util.LRUCache;

/**
 * An LRU cache of <code>JavaElements</code>.
 */
public class ElementCache extends OverflowingLRUCache {
	/**
	 * Constructs a new element cache of the given size.
	 */
	public ElementCache(int size) {
		super(size);
	}

	/**
	 * Constructs a new element cache of the given size.
	 */
	public ElementCache(int size, int overflow) {
		super(size, overflow);
	}

	/**
	 * Returns true if the element is successfully closed and removed from the
	 * cache, otherwise false.
	 * 
	 * <p>
	 * NOTE: this triggers an external removal of this element by closing the
	 * element.
	 */
	protected boolean close(LRUCacheEntry entry) {
		IOpenable element = (IOpenable) entry._fKey;
		try {
			if (element.hasUnsavedChanges()) {
				return false;
			} else {
				// We must close an entire JarPackageFragmentRoot at once.
				// if (element instanceof JarPackageFragment) {
				// JarPackageFragment packageFragment= (JarPackageFragment)
				// element;
				// JarPackageFragmentRoot root = (JarPackageFragmentRoot)
				// packageFragment.getParent();
				// root.close();
				// } else {
				element.close();
				// }
				return true;
			}
		} catch (JavaModelException npe) {
			return false;
		}
	}

	/**
	 * Returns a new instance of the reciever.
	 */
	protected LRUCache newInstance(int size, int overflow) {
		return new ElementCache(size, overflow);
	}
}