/*
 * JBoss, Home of Professional Open Source
 * Copyright 2011 Red Hat Inc. and/or its affiliates and other contributors
 * as indicated by the @authors tag. All rights reserved.
 * See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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, v. 2.1.
 * This program is distributed in the hope that it will be useful, but WITHOUT A
 * 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,
 * v.2.1 along with this distribution; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 */

package org.hibernate.search.annotations;

/**
 * How should we interact with Lucene's {@code FieldCache}.
 * {@code FieldCache}s can provide a good performance boost
 * but will keep soft references to large arrays of values in memory.
 * This effectively caches stored values from the index to reduce seek times.
 *
 * @author Sanne Grinovero <sanne@hibernate.org> (C) 2011 Red Hat Inc.
 * @see org.apache.lucene.search.FieldCache
 */
public enum FieldCacheType {

	/**
	 * Disable all caching options. (ie CLASS, ID)
	 * CacheFromIndex(NOTHING) or CacheFromIndex(value=FieldCacheType[]{}) are equivalent.
	 */
	NOTHING,

	/**
	 * Cache the entity type. This is a good tradeoff in most cases as
	 * it enables some optimizations; Depending on the query the type might not be
	 * needed, in which case the FieldCache won't be used.
	 */
	CLASS,

	/**
	 * Attempts to the object identifier (@DocumentId).
	 * Not all identifier types are supported.
	 */
	ID
}
