com.cloudera.sqoop.testutil.SeqFileReader.java Source code

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Here is the source code for com.cloudera.sqoop.testutil.SeqFileReader.java

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/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. 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.cloudera.sqoop.testutil;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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.hadoop.io.SequenceFile.Reader;
import org.apache.hadoop.util.ReflectionUtils;

/**
 * Utility class to help with test cases. Just reads the first (k, v) pair
 * from a SequenceFile and returns the value part.
 * 
 *
 */
public final class SeqFileReader {

    private SeqFileReader() {
    }

    public static final Log LOG = LogFactory.getLog(SeqFileReader.class.getName());

    public static Reader getSeqFileReader(String filename) throws IOException {
        // read from local filesystem
        Configuration conf = new Configuration();
        if (!BaseSqoopTestCase.isOnPhysicalCluster()) {
            conf.set(CommonArgs.FS_DEFAULT_NAME, CommonArgs.LOCAL_FS);
        }
        FileSystem fs = FileSystem.get(conf);
        LOG.info("Opening SequenceFile " + filename);
        return new SequenceFile.Reader(fs, new Path(filename), conf);
    }

    public static Object getFirstValue(String filename) throws IOException {
        Reader r = null;
        try {
            // read from local filesystem
            Configuration conf = new Configuration();
            if (!BaseSqoopTestCase.isOnPhysicalCluster()) {
                conf.set(CommonArgs.FS_DEFAULT_NAME, CommonArgs.LOCAL_FS);
            }
            FileSystem fs = FileSystem.get(conf);
            r = new SequenceFile.Reader(fs, new Path(filename), conf);
            Object key = ReflectionUtils.newInstance(r.getKeyClass(), conf);
            Object val = ReflectionUtils.newInstance(r.getValueClass(), conf);
            LOG.info("Reading value of type " + r.getValueClassName() + " from SequenceFile " + filename);
            r.next(key);
            r.getCurrentValue(val);
            LOG.info("Value as string: " + val.toString());
            return val;
        } finally {
            if (null != r) {
                try {
                    r.close();
                } catch (IOException ioe) {
                    LOG.warn("IOException during close: " + ioe.toString());
                }
            }
        }
    }
}