org.apache.lens.lib.query.FilePersistentFormatter.java Source code

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Here is the source code for org.apache.lens.lib.query.FilePersistentFormatter.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.lens.lib.query;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.ParseException;
import java.util.Map;
import java.util.TreeMap;

import org.apache.lens.server.api.driver.LensResultSetMetadata;
import org.apache.lens.server.api.query.PersistedOutputFormatter;
import org.apache.lens.server.api.query.QueryContext;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;

/**
 * File formatter for {@link PersistedOutputFormatter}
 * <p/>
 * This is a {@link WrappedFileFormatter} which can wrap any {@link FileFormatter}.
 */
public class FilePersistentFormatter extends WrappedFileFormatter implements PersistedOutputFormatter {

    /**
     * The Constant LOG.
     */
    public static final Log LOG = LogFactory.getLog(FilePersistentFormatter.class);

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.lib.query.WrappedFileFormatter#init(org.apache.lens.server.api.query.QueryContext,
     * org.apache.lens.server.api.driver.LensResultSetMetadata)
     */
    public void init(QueryContext ctx, LensResultSetMetadata metadata) throws IOException {
        super.init(ctx, metadata);
    }

    // File names are of the form 000000_0

    /**
     * The Class PartFile.
     */
    class PartFile implements Comparable<PartFile> {

        /**
         * The id.
         */
        int id;

        /**
         * Instantiates a new part file.
         *
         * @param fileName the file name
         * @throws ParseException the parse exception
         */
        PartFile(String fileName) throws ParseException {
            String idStr = fileName.substring(0, fileName.lastIndexOf('_'));
            id = Integer.parseInt(idStr);
        }

        /*
         * (non-Javadoc)
         *
         * @see java.lang.Comparable#compareTo(java.lang.Object)
         */
        @Override
        public int compareTo(PartFile other) {
            if (this.id < other.id) {
                return -1;
            } else if (this.id > other.id) {
                return 1;
            }
            return 0;
        }
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.server.api.query.PersistedOutputFormatter#addRowsFromPersistedPath(org.apache.hadoop.fs.Path)
     */
    @Override
    public void addRowsFromPersistedPath(Path persistedDir) throws IOException {
        FileSystem persistFs = persistedDir.getFileSystem(ctx.getConf());

        FileStatus[] partFiles = persistFs.listStatus(persistedDir, new PathFilter() {
            @Override
            public boolean accept(Path path) {
                if (path.getName().startsWith("_")) {
                    return false;
                }
                return true;
            }
        });

        TreeMap<PartFile, FileStatus> partFileMap = new TreeMap<PartFile, FileStatus>();
        try {
            for (FileStatus file : partFiles) {
                partFileMap.put(new PartFile(file.getPath().getName()), file);
            }

            for (Map.Entry<PartFile, FileStatus> entry : partFileMap.entrySet()) {
                LOG.info("Processing file:" + entry.getValue().getPath());
                BufferedReader in = null;
                try {
                    in = new BufferedReader(new InputStreamReader(persistFs.open(entry.getValue().getPath())));
                    String row = in.readLine();
                    while (row != null) {
                        writeRow(row);
                        row = in.readLine();
                    }
                } finally {
                    if (in != null) {
                        in.close();
                    }
                }
            }
        } catch (ParseException e) {
            throw new IOException(e);
        }
    }
}