com.topsoft.botspider.util.GetSchemaTool.java Source code

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Here is the source code for com.topsoft.botspider.util.GetSchemaTool.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 com.topsoft.botspider.util;

import java.io.InputStream;
import java.io.PrintStream;
import java.util.List;

import org.apache.avro.file.DataFileReader;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import com.topsoft.botspider.avro.mapreduce.FsInput;
import com.topsoft.botspider.io.MapAvroFile;

/** Reads a data file to get its schema. */
public class GetSchemaTool implements Tool {

    @Override
    public String getName() {
        return "getschema";
    }

    @Override
    public String getShortDescription() {
        return "Prints out schema of an Avro data file.";
    }

    @Override
    public int run(InputStream stdin, PrintStream out, PrintStream err, List<String> args) throws Exception {
        if (args.size() != 1) {
            err.println("Usage: input_file");
            return 1;
        }
        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(conf);
        Path inpitFile = new Path(args.get(0));
        if (fs.isDirectory(inpitFile)) {
            inpitFile = new Path(inpitFile, MapAvroFile.DATA_FILE_NAME);
        }
        DataFileReader<Void> reader = new DataFileReader<Void>(new FsInput(inpitFile, conf),
                new GenericDatumReader<Void>());
        try {

            out.println(reader.getSchema().toString(true));

        } finally {
            reader.close();
        }
        return 0;
    }
}