/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.cache;

import java.util.Map;

/**
 * Defines a contract for accessing a particular named region within the 
 * underlying cache implementation.
 *
 * @author Steve Ebersole
 */
public interface Region {
	/**
	 * Retrieve the name of this region.
	 *
	 * @return The region name
	 */
	public String getName();

	/**
	 * The "end state" contract of the region's lifecycle.  Called
	 * during {@link org.hibernate.SessionFactory#close()} to give
	 * the region a chance to cleanup.
	 *
	 * @throws CacheException Indicates problem shutting down
	 */
	public void destroy() throws CacheException;

	/**
	 * Determine whether this region contains data for the given key.
	 * <p/>
	 * The semantic here is whether the cache contains data visible for the
	 * current call context.  This should be viewed as a "best effort", meaning
	 * blocking should be avoid if possible.
	 *
	 * @param key The cache key
	 *
	 * @return True if the underlying cache contains corresponding data; false
	 * otherwise.
	 */
	public boolean contains(Object key);

	/**
	 * The number of bytes is this cache region currently consuming in memory.
	 *
	 * @return The number of bytes consumed by this region; -1 if unknown or
	 * unsupported.
	 */
	public long getSizeInMemory();

	/**
	 * The count of entries currently contained in the regions in-memory store.
	 *
	 * @return The count of entries in memory; -1 if unknown or unsupported.
	 */
	public long getElementCountInMemory();

	/**
	 * The count of entries currently contained in the regions disk store.
	 *
	 * @return The count of entries on disk; -1 if unknown or unsupported.
	 */
	public long getElementCountOnDisk();

	/**
	 * Get the contents of this region as a map.
	 * <p/>
	 * Implementors which do not support this notion
	 * should simply return an empty map.
	 *
	 * @return The content map.
	 */
	public Map toMap();

	public long nextTimestamp();
	public int getTimeout();
}
