/*[INCLUDE-IF Sidecar18-SE]*/
/*
 * Copyright IBM Corp. and others 2006
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 */
package com.ibm.dtfj.corereaders.zos.util;

/**
 * This class provides an LRU (Least Recently Used) cache which maps integer keys to object values.
 * See the description in the superclass {@link com.ibm.dtfj.corereaders.zos.util.AbstractLruCache} for more
 * details.
 */

public final class ObjectLruCache extends AbstractLruCache {

	/** The array of values */
	Object[] values = new Object[INITIAL_SIZE];

	/**
	 * Create a new ObjectLruCache.
	 * @param maxSize the maximum size the cache can grow to
	 */
	public ObjectLruCache(int maxSize) {
		super(maxSize);
	}

	/**
	 * Overridden method to return values array.
	 */
	Object getValuesArray() {
		return values;
	}

	/**
	 * Overridden method to allocate new values array.
	 */
	void allocNewValuesArray(int newSize) {
		super.allocNewValuesArray(newSize);
		values = new Object[newSize];
	}

	/**
	 * Overridden method to repopulate with key plus value at given offset.
	 */
	void put(long key, Object oldvalues, int offset) {
		Object[] v = (Object[])oldvalues;
		put(key, v[offset]);
	}

	/**
	 * Returns the value mapped by the given key. Also promotes this key to the most
	 * recently used.
	 * @return the value or null if it cannot be found
	 */
	public Object get(long key) {
		int index = getIndexAndPromote(key) ;
		if (index != -1) {
			return values[index];
		}
		return null;
	}

	/**
	 * Add the key/value pair to the map.
	 */
	public void put(long key, Object value) {
		int index = putIndexAndPromote(key) ;
		values[index] = value;
		checkRehash();
	}
}
