hyracks/hyracks-storage-common/src/main/java/edu/uci/ics/hyracks/storage/common/buffercache/IPageCleanerPolicy.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.storage.common.buffercache;

import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;

/**
 * Allows customization of the page cleaning strategy by the cleaner thread.
 * 
 * @author vinayakb
 */
public interface IPageCleanerPolicy {
    /**
     * Callback from the cleaner just before the beginning of a cleaning cycle.
     * 
     * @param monitor
     *            - The monitor on which a mutex is held while in this call
     * @throws HyracksDataException
     */
    public void notifyCleanCycleStart(Object monitor) throws HyracksDataException;

    /**
     * Callback from the cleaner just after the finish of a cleaning cycle.
     * 
     * @param monitor
     *            - The monitor on which a mutex is held while in this call.
     * @throws HyracksDataException
     */
    public void notifyCleanCycleFinish(Object monitor) throws HyracksDataException;

    /**
     * Callback to indicate that no victim was found.
     * 
     * @param monitor
     *            - The monitor on which a mutex is held while in this call.
     * @throws HyracksDataException
     */
    public void notifyVictimNotFound(Object monitor) throws HyracksDataException;
}