com.citic.zxyjs.zwlscx.mapreduce.join.api.TaggedMapOutput.java Source code

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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.citic.zxyjs.zwlscx.mapreduce.join.api;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableUtils;

/**
 * This abstract class serves as the base class for the values that flow from
 * the mappers to the reducers in a data join job. Typically, in such a job, the
 * mappers will compute the source tag of an input record based on its
 * attributes or based on the file name of the input file. This tag will be used
 * by the reducers to re-group the values of a given key according to their
 * source tags.
 */
public abstract class TaggedMapOutput implements Writable {
    protected Text tag;

    public TaggedMapOutput() {
        this.tag = new Text("");
    }

    public Text getTag() {
        return tag;
    }

    public void setTag(Text tag) {
        this.tag = tag;
    }

    public abstract Writable getData();

    public TaggedMapOutput clone(Configuration conf) {
        return (TaggedMapOutput) WritableUtils.clone(this, conf);
    }

}