co.cask.cdap.etl.batch.mapreduce.TaggedWritable.java Source code

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Here is the source code for co.cask.cdap.etl.batch.mapreduce.TaggedWritable.java

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/*
 * Copyright  2016 Cask Data, Inc.
 *
 * 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 co.cask.cdap.etl.batch.mapreduce;

import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.ObjectWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

/**
 * Map output for which includes stageName and the record provided. This can be used to tag map output with stageName.
 * @param <RECORD> Writable record to be serialized along with stageName
 */
public class TaggedWritable<RECORD extends Writable>
        implements WritableComparable<TaggedWritable<RECORD>>, Configurable {
    private String stageName;
    private RECORD record;
    private Configuration conf;
    private ObjectWritable recordWritable;

    // required by Hadoop
    @SuppressWarnings("unused")
    public TaggedWritable() {
    }

    public TaggedWritable(String stageName, RECORD record) {
        this.stageName = stageName;
        this.record = record;
    }

    public String getStageName() {
        return stageName;
    }

    public RECORD getRecord() {
        return record;
    }

    public void setStageName(String stageName) {
        this.stageName = stageName;
    }

    public void setRecord(RECORD record) {
        this.record = record;
    }

    @Override
    public int compareTo(TaggedWritable o) {
        return Integer.compare(hashCode(), o.hashCode());
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        TaggedWritable that = (TaggedWritable) o;
        return that.stageName.equals(stageName) && that.record.equals(record);
    }

    @Override
    public int hashCode() {
        return (record != null && stageName != null) ? record.hashCode() + stageName.hashCode() : 0;
    }

    @Override
    public void write(DataOutput out) throws IOException {
        Text.writeString(out, stageName);
        ObjectWritable recordWritable = new ObjectWritable(record);
        recordWritable.write(out);
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        this.stageName = Text.readString(in);
        this.recordWritable.readFields(in);
        this.record = (RECORD) recordWritable.get();
    }

    @Override
    public void setConf(Configuration conf) {
        this.conf = conf;
        recordWritable = new ObjectWritable();
        // ObjectWritable does not set conf while reading fields
        recordWritable.setConf(conf);
    }

    @Override
    public Configuration getConf() {
        return conf;
    }
}