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

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Here is the source code for com.cloudera.sqoop.mapreduce.MergeRecord.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.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;

import com.cloudera.sqoop.lib.SqoopRecord;

/**
 * Class that holds a record to be merged. This contains a SqoopRecord which
 * is the "guts" of the item, and a boolean value indicating whether it is a
 * "new" record or an "old" record. In the Reducer, we prefer to emit a new
 * record rather than an old one, if a new one is available.
 */
public class MergeRecord implements Configurable, Writable {
    private SqoopRecord sqoopRecord;
    private boolean isNew;
    private Configuration config;

    /** Construct an empty MergeRecord. */
    public MergeRecord() {
        this.sqoopRecord = null;
        this.isNew = false;
        this.config = new Configuration();
    }

    /**
     * Construct a MergeRecord with all fields initialized.
     */
    public MergeRecord(SqoopRecord sr, boolean recordIsNew) {
        this.sqoopRecord = sr;
        this.isNew = recordIsNew;
        this.config = new Configuration();
    }

    @Override
    /** {@inheritDoc} */
    public void setConf(Configuration conf) {
        this.config = conf;
    }

    @Override
    /** {@inheritDoc} */
    public Configuration getConf() {
        return this.config;
    }

    /** @return true if this record came from the "new" dataset. */
    public boolean isNewRecord() {
        return isNew;
    }

    /** 
     * Set the isNew field to 'newVal'.
     */
    public void setNewRecord(boolean newVal) {
        this.isNew = newVal;
    }

    /**
     * @return the underlying SqoopRecord we're shipping.
     */
    public SqoopRecord getSqoopRecord() {
        return this.sqoopRecord;
    }

    /**
     * Set the SqoopRecord instance we should pass from the mapper to the
     * reducer.
     */
    public void setSqoopRecord(SqoopRecord record) {
        this.sqoopRecord = record;
    }

    @Override
    /**
     * {@inheritDoc}
     */
    public void readFields(DataInput in) throws IOException {
        this.isNew = in.readBoolean();
        String className = Text.readString(in);
        if (null == this.sqoopRecord) {
            // If we haven't already instantiated an inner SqoopRecord, do so here.
            try {
                Class<? extends SqoopRecord> recordClass = (Class<? extends SqoopRecord>) config
                        .getClassByName(className);
                this.sqoopRecord = recordClass.newInstance();
            } catch (Exception e) {
                throw new IOException(e);
            }
        }

        this.sqoopRecord.readFields(in);
    }

    @Override
    /**
     * {@inheritDoc}
     */
    public void write(DataOutput out) throws IOException {
        out.writeBoolean(this.isNew);
        Text.writeString(out, this.sqoopRecord.getClass().getName());
        this.sqoopRecord.write(out);
    }

    @Override
    public String toString() {
        return "" + this.sqoopRecord;
    }
}