io.druid.query.ReferenceCountingSegmentQueryRunner.java Source code

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Here is the source code for io.druid.query.ReferenceCountingSegmentQueryRunner.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012, 2013  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package io.druid.query;

import com.google.common.io.Closeables;
import com.metamx.common.guava.ResourceClosingSequence;
import com.metamx.common.guava.Sequence;
import io.druid.segment.ReferenceCountingSegment;

import java.io.Closeable;

/**
*/
public class ReferenceCountingSegmentQueryRunner<T> implements QueryRunner<T> {
    private final QueryRunnerFactory<T, Query<T>> factory;
    private final ReferenceCountingSegment adapter;

    public ReferenceCountingSegmentQueryRunner(QueryRunnerFactory<T, Query<T>> factory,
            ReferenceCountingSegment adapter) {
        this.factory = factory;
        this.adapter = adapter;
    }

    @Override
    public Sequence<T> run(final Query<T> query) {
        final Closeable closeable = adapter.increment();
        try {
            final Sequence<T> baseSequence = factory.createRunner(adapter).run(query);

            return new ResourceClosingSequence<T>(baseSequence, closeable);
        } catch (RuntimeException e) {
            Closeables.closeQuietly(closeable);
            throw e;
        }
    }
}