com.cloudera.sqoop.mapreduce.MergeMapperBase.java Source code

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Here is the source code for com.cloudera.sqoop.mapreduce.MergeMapperBase.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.mapreduce;

import java.io.IOException;

import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;

import com.cloudera.sqoop.lib.SqoopRecord;

/**
 * Given a set of SqoopRecord instances which are from a "new" dataset
 * or an "old" dataset, extract a key column from the record and tag
 * each record with a bit specifying whether it is a new or old record.
 */
public class MergeMapperBase<INKEY, INVAL> extends Mapper<INKEY, INVAL, Text, MergeRecord> {

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

    private String keyColName; // name of the key column.
    private boolean isNew; // true if this split is from the new dataset. 

    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
        Configuration conf = context.getConfiguration();
        keyColName = conf.get(MergeJob.MERGE_KEY_COL_KEY);

        InputSplit is = context.getInputSplit();
        FileSplit fs = (FileSplit) is;
        Path splitPath = fs.getPath();

        if (splitPath.toString().startsWith(conf.get(MergeJob.MERGE_NEW_PATH_KEY))) {
            this.isNew = true;
        } else if (splitPath.toString().startsWith(conf.get(MergeJob.MERGE_OLD_PATH_KEY))) {
            this.isNew = false;
        } else {
            throw new IOException(
                    "File " + splitPath + " is not under new path " + conf.get(MergeJob.MERGE_NEW_PATH_KEY)
                            + " or old path " + conf.get(MergeJob.MERGE_OLD_PATH_KEY));
        }
    }

    protected void processRecord(SqoopRecord r, Context c) throws IOException, InterruptedException {
        MergeRecord mr = new MergeRecord(r, isNew);
        Map<String, Object> fieldMap = r.getFieldMap();
        if (null == fieldMap) {
            throw new IOException("No field map in record " + r);
        }
        Object keyObj = fieldMap.get(keyColName);
        if (null == keyObj) {
            throw new IOException("Cannot join values on null key. " + "Did you specify a key column that exists?");
        } else {
            c.write(new Text(keyObj.toString()), mr);
        }
    }
}