com.datasalt.utils.commons.io.DumpSequenceFileAsText.java Source code

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Here is the source code for com.datasalt.utils.commons.io.DumpSequenceFileAsText.java

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/**
 * Copyright [2011] [Datasalt Systems S.L.]
 *
 * 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 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 com.datasalt.utils.commons.io;

import java.net.URL;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Properties;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.SequenceFile;
import org.apache.thrift.TBase;

import com.datasalt.utils.commons.BaseJob;
import com.datasalt.utils.commons.ThriftUtils;

/**
 * Utility for seing Sequence Files content as text. Thrift objects are dump as human readable JSON. The rest of objects
 * are dump by calling the toString()
 * 
 * @author ivan
 */
@SuppressWarnings({ "rawtypes" })
public class DumpSequenceFileAsText extends BaseJob {

    private final static String HELP = "Arguments: [options] [input] \n\n"
            + "Utility for seen Sequence Files content as text. Thrift objects are dump"
            + "as humal readable JSON. The rest of objects are dump by calling the toString() \n\n" + "Options:\n\n"
            + "\t\t-l\t\tUse local filesystem\n" + "\t\t-p pos\t\tStart at the given file position\n"
            + "\t\t-n rows\t\tReturn only n rows";

    public DumpSequenceFileAsText() {
    }

    @Override
    public void execute(String[] args, Configuration conf) throws Exception {
        boolean localFilesystem = false;
        long pos = -1;
        long rows = -1;

        // Command line parsing
        ArrayList<String> parameters = new ArrayList<String>();
        for (int i = 0; i < args.length; i++) {
            if ("-l".equals(args[i])) {
                localFilesystem = true;
            } else if ("-p".equals(args[i])) {
                pos = new Long(args[++i]);
            } else if ("-n".equals(args[i])) {
                rows = new Long(args[++i]);
            } else {
                parameters.add(args[i]);
            }
        }

        if (parameters.size() != 1) {
            System.out.println(HELP);
            throw new IllegalArgumentException("Invalid number of arguments");
        }

        FileSystem fs;
        if (localFilesystem) {
            fs = FileSystem.getLocal(conf);
        } else {
            fs = FileSystem.get(conf);
        }

        SequenceFile.Reader reader = new SequenceFile.Reader(fs, new Path(parameters.get(0)), conf);

        // Syncing the file at a position
        if (pos != -1) {
            reader.sync(pos);
        }

        // Creating objects for reading
        Object key = reader.getKeyClass().newInstance();
        Object value = null;
        try {
            value = reader.getValueClass().newInstance();
        } catch (Exception e) {
            System.err.println(" Warning : Couldn't get a reader class instantated : " + e.getMessage()
                    + " --- NullWritable objects are known to cause this problem.");
        }

        int count = 0;

        while ((reader.next(key) != null)) {

            if (rows != -1 && count == rows) {
                break;
            }

            if (value != null) {
                reader.getCurrentValue(value);
            }

            if (value != null) {
                System.out.println(stringfy(key) + "\t" + stringfy(value));
            } else {
                System.out.println("key=" + stringfy(key));
            }

            count++;
        }
        System.err.println("done.");

        reader.close();
    }

    private String stringfy(Object o) {
        if (o == null)
            return "#this value was null#";
        if (o instanceof TBase) {
            return ThriftUtils.toJSON((TBase) o);
        } else {
            return o.toString();
        }
    }

    /**
     * To run just send the file path as the first arg.
     * 
     * @param args
     * @throws Exception
     */
    public static void main(String args[]) throws Exception {
        BaseJob.main(DumpSequenceFileAsText.class, args);
    }

    @Override
    public double getProgress() throws Exception {
        return 0;
    }

    @Override
    public void cancel() throws Exception {
    }

    @Override
    public Properties getJobGeneratedProperties() {
        return new Properties();
    }

}