/*
 * Copyright (C) 2004-2008 Jive Software. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.util.cache;

/**
 * Interface that defines the necessary behavior for objects added to a Cache.
 * Objects only need to know how big they are (in bytes). That size
 * should be considered to be a best estimate of how much memory the Object
 * occupies and may be based on empirical trials or dynamic calculations.<p>
 *
 * While the accuracy of the size calculation is important, care should be
 * taken to minimize the computation time so that cache operations are
 * speedy.
 *
 * @author Jive Software
 * @see org.jivesoftware.util.cache.Cache
 */
public interface Cacheable extends java.io.Serializable {

    /**
     * Returns the approximate size of the Object in bytes. The size should be
     * considered to be a best estimate of how much memory the Object occupies
     * and may be based on empirical trials or dynamic calculations.<p>
     *
     * @return the size of the Object in bytes.
     * @throws CannotCalculateSizeException if the size cannot be calculated
     */
    int getCachedSize() throws CannotCalculateSizeException;
}
