Java tutorial
/******************************************************************************* * Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 * which accompanies this distribution. * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * http://www.eclipse.org/org/documents/edl-v10.php. * * Contributors: * Linda DeMichiel - Java Persistence 2.1 * Linda DeMichiel - Java Persistence 2.0 * ******************************************************************************/ package javax.persistence; /** * Interface used to interact with the second-level cache. * If a cache is not in use, the methods of this interface have * no effect, except for <code>contains</code>, which returns false. * * @since Java Persistence 2.0 */ public interface Cache { /** * Whether the cache contains data for the given entity. * @param cls entity class * @param primaryKey primary key * @return boolean indicating whether the entity is in the cache */ public boolean contains(Class cls, Object primaryKey); /** * Remove the data for the given entity from the cache. * @param cls entity class * @param primaryKey primary key */ public void evict(Class cls, Object primaryKey); /** * Remove the data for entities of the specified class (and its * subclasses) from the cache. * @param cls entity class */ public void evict(Class cls); /** * Clear the cache. */ public void evictAll(); /** * Return an object of the specified type to allow access to the * provider-specific API. If the provider's Cache * implementation does not support the specified class, the * PersistenceException is thrown. * @param cls the class of the object to be returned. This is * normally either the underlying Cache implementation * class or an interface that it implements. * @return an instance of the specified class * @throws PersistenceException if the provider does not * support the call * @since Java Persistence 2.1 */ public <T> T unwrap(Class<T> cls); }