/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.cache.ehcache.internal.strategy;

import org.hibernate.boot.spi.SessionFactoryOptions;
import org.hibernate.cache.CacheException;
import org.hibernate.cache.ehcache.internal.regions.EhcacheTransactionalDataRegion;
import org.hibernate.cache.spi.access.RegionAccessStrategy;
import org.hibernate.cache.spi.access.SoftLock;
import org.hibernate.engine.spi.SharedSessionContractImplementor;

/**
 * Ultimate superclass for all Ehcache specific Hibernate AccessStrategy implementations.
 *
 * @param <T> type of the enclosed region
 *
 * @author Chris Dennis
 * @author Alex Snaps
 */
abstract class AbstractEhcacheAccessStrategy<T extends EhcacheTransactionalDataRegion> {
	private final T region;
	private final SessionFactoryOptions settings;

	/**
	 * Create an access strategy wrapping the given region.
	 *
	 * @param region The wrapped region.  Accessible to subclasses via {@link #region()}
	 * @param settings The Hibernate settings.  Accessible to subclasses via {@link #settings()}
	 */
	AbstractEhcacheAccessStrategy(T region, SessionFactoryOptions settings) {
		this.region = region;
		this.settings = settings;
	}

	/**
	 * The wrapped Hibernate cache region.
	 */
	protected T region() {
		return region;
	}

	/**
	 * The settings for this persistence unit.
	 */
	protected SessionFactoryOptions settings() {
		return settings;
	}

	/**
	 * This method is a placeholder for method signatures supplied by interfaces pulled in further down the class
	 * hierarchy.
	 *
	 * @see RegionAccessStrategy#putFromLoad(SharedSessionContractImplementor, Object, Object, long, Object)
	 * @see RegionAccessStrategy#putFromLoad(SharedSessionContractImplementor, Object, Object, long, Object)
	 */
	public final boolean putFromLoad(SharedSessionContractImplementor session, Object key, Object value, long txTimestamp, Object version) throws CacheException {
		return putFromLoad( session, key, value, txTimestamp, version, settings.isMinimalPutsEnabled() );
	}

	/**
	 * This method is a placeholder for method signatures supplied by interfaces pulled in further down the class
	 * hierarchy.
	 *
	 * @see RegionAccessStrategy#putFromLoad(SharedSessionContractImplementor, Object, Object, long, Object, boolean)
	 * @see RegionAccessStrategy#putFromLoad(SharedSessionContractImplementor, Object, Object, long, Object, boolean)
	 */
	public abstract boolean putFromLoad(SharedSessionContractImplementor session, Object key, Object value, long txTimestamp, Object version, boolean minimalPutOverride)
			throws CacheException;

	/**
	 * Region locks are not supported.
	 *
	 * @return <code>null</code>
	 *
	 * @see org.hibernate.cache.spi.access.EntityRegionAccessStrategy#lockRegion()
	 * @see org.hibernate.cache.spi.access.CollectionRegionAccessStrategy#lockRegion()
	 */
	@SuppressWarnings("UnusedDeclaration")
	public final SoftLock lockRegion() {
		return null;
	}

	/**
	 * Region locks are not supported - perform a cache clear as a precaution.
	 *
	 * @see org.hibernate.cache.spi.access.EntityRegionAccessStrategy#unlockRegion(org.hibernate.cache.spi.access.SoftLock)
	 * @see org.hibernate.cache.spi.access.CollectionRegionAccessStrategy#unlockRegion(org.hibernate.cache.spi.access.SoftLock)
	 */
	@SuppressWarnings("UnusedDeclaration")
	public final void unlockRegion(SoftLock lock) throws CacheException {
		region.clear();
	}

	/**
	 * A no-op since this is an asynchronous cache access strategy.
	 *
	 * @see RegionAccessStrategy#remove(SharedSessionContractImplementor, Object)
	 * @see RegionAccessStrategy#remove(SharedSessionContractImplementor, Object)
	 */
	public void remove(SharedSessionContractImplementor session, Object key) throws CacheException {
	}

	/**
	 * Called to evict data from the entire region
	 *
	 * @throws CacheException Propogated from underlying {@link org.hibernate.cache.spi.Region}
	 * @see org.hibernate.cache.spi.access.EntityRegionAccessStrategy#removeAll()
	 * @see org.hibernate.cache.spi.access.CollectionRegionAccessStrategy#removeAll()
	 */
	@SuppressWarnings("UnusedDeclaration")
	public final void removeAll() throws CacheException {
		region.clear();
	}

	/**
	 * Remove the given mapping without regard to transactional safety
	 *
	 * @see org.hibernate.cache.spi.access.EntityRegionAccessStrategy#evict(java.lang.Object)
	 * @see org.hibernate.cache.spi.access.CollectionRegionAccessStrategy#evict(java.lang.Object)
	 */
	public final void evict(Object key) throws CacheException {
		region.remove( key );
	}

	/**
	 * Remove all mappings without regard to transactional safety
	 *
	 * @see org.hibernate.cache.spi.access.EntityRegionAccessStrategy#evictAll()
	 * @see org.hibernate.cache.spi.access.CollectionRegionAccessStrategy#evictAll()
	 */
	@SuppressWarnings("UnusedDeclaration")
	public final void evictAll() throws CacheException {
		region.clear();
	}
}