com.metamx.druid.loading.MMappedQueryableIndexFactory.java Source code

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Here is the source code for com.metamx.druid.loading.MMappedQueryableIndexFactory.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  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 com.metamx.druid.loading;

import com.metamx.common.logger.Logger;
import com.metamx.druid.index.QueryableIndex;
import com.metamx.druid.index.v1.IndexIO;
import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;

/**
 */
public class MMappedQueryableIndexFactory implements QueryableIndexFactory {
    private static final Logger log = new Logger(MMappedQueryableIndexFactory.class);

    @Override
    public QueryableIndex factorize(File parentDir) throws SegmentLoadingException {
        try {
            if (!IndexIO.canBeMapped(parentDir)) {
                File canBeMappedDir = new File(parentDir, "forTheMapping");
                if (canBeMappedDir.exists()) {
                    FileUtils.deleteDirectory(canBeMappedDir);
                }
                canBeMappedDir.mkdirs();

                IndexIO.storeLatest(IndexIO.readIndex(parentDir), canBeMappedDir);
                if (!IndexIO.canBeMapped(canBeMappedDir)) {
                    throw new SegmentLoadingException("WTF!? newly written file[%s] cannot be mapped!?",
                            canBeMappedDir);
                }
                for (File file : canBeMappedDir.listFiles()) {
                    if (!file.renameTo(new File(parentDir, file.getName()))) {
                        throw new SegmentLoadingException("Couldn't rename[%s] to [%s]", canBeMappedDir, parentDir);
                    }
                }
                FileUtils.deleteDirectory(canBeMappedDir);
            }

            return IndexIO.loadIndex(parentDir);
        } catch (IOException e) {
            log.warn(e, "Got exception!!!! Going to delete parentDir[%s]", parentDir);
            try {
                FileUtils.deleteDirectory(parentDir);
            } catch (IOException e2) {
                log.error(e, "Problem deleting parentDir[%s]", parentDir);
            }
            throw new SegmentLoadingException(e, "%s", e.getMessage());
        }
    }
}