/*
 * Copyright 2009-2012 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.am.lsm.common.impls;

import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndex;
import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexAccessor;
import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMMergePolicy;

public class ConstantMergePolicy implements ILSMMergePolicy {

    private final int threshold;

    public ConstantMergePolicy(int threshold) {
        this.threshold = threshold;
    }

    @Override
    public void diskComponentAdded(final ILSMIndex index, int totalNumDiskComponents) throws HyracksDataException,
            IndexException {
        if (totalNumDiskComponents >= threshold) {
            ILSMIndexAccessor accessor = (ILSMIndexAccessor) index.createAccessor(NoOpOperationCallback.INSTANCE,
                    NoOpOperationCallback.INSTANCE);
            accessor.scheduleMerge(NoOpIOOperationCallback.INSTANCE);
        }
    }
}