com.datatorrent.lib.join.MapJoinOperator Maven / Gradle / Ivy

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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.datatorrent.lib.join;

import java.util.Calendar;
import java.util.HashMap;
import java.util.Map;

import org.apache.hadoop.classification.InterfaceStability;

/**
 * This class takes a HashMap tuple as input from each of the input port. Operator joines the input tuples
 * based on join constraint and emit the result.
 *
 * 

 * Ports :  

 *  input1 :  Input port for stream 1, expects HashMap<String, Object> 

 *  input2 :  Input port for stream 2, expects HashMap<String, Object> 

 *  outputPort:  Output port emits ArrayList<HashMap<String, Object>> 

 * 

 * Example:
 * Input tuple from port1 is
 * {timestamp = 5000, productId = 3, customerId = 108, regionId = 4, amount = $560 }
 *
 * Input tuple from port2 is
 * { timestamp = 5500, productCategory = 8, productId=3 }
 *
 * Properties: 
 * expiryTime: 1000

 * includeFieldStr: timestamp, customerId, amount; productCategory, productId

 * keyFields: productId, productId

 * timeFields: timestamp, timestamp

 * bucketSpanInMillis: 500

 *
 * Output
 * { timestamp = 5000, customerId = 108, amount = $560, productCategory = 8, productId=3}
 *
 * @displayName MapJoin Operator
 * @category join
 * @tags join
 *
 * @since 3.4.0
 */
@InterfaceStability.Unstable
public class MapJoinOperator extends AbstractJoinOperator>
{
  @Override
  protected Map createOutputTuple()
  {
    return new HashMap();
  }

  @Override
  protected void copyValue(Map output, Object extractTuple, boolean isLeft)
  {
    String[] fields;
    if (isLeft) {
      fields = leftStore.getIncludeFields();
    } else {
      fields = rightStore.getIncludeFields();
    }
    for (int i = 0; i < fields.length; i++) {
      Object value = null;
      if (extractTuple != null) {
        value = ((Map)extractTuple).get(fields[i]);
      }
      output.put(fields[i], value);
    }
  }

  public Object getKeyValue(String keyField, Object tuple)
  {
    Map o = (Map)tuple;
    return o.get(keyField);
  }

  @Override
  protected Object getTime(String field, Object tuple)
  {
    if (getTimeFieldStr() != null) {
      Map o = (Map)tuple;
      return o.get(field);
    }
    return Calendar.getInstance().getTimeInMillis();
  }
}