datafu.hourglass.model.Merger Maven / Gradle / Ivy

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/**
* Copyright 2013 LinkedIn, 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 datafu.hourglass.model;

import java.io.Serializable;

/**
 * Merges two values together.
 * 
 * @author "Matthew Hayes"
 *
 * @param  Value type
 */
public interface Merger extends Serializable
{
  /**
   * Merges two values together.
   * 
   * 
   * This may return null to indicate no record should be written.
   * 
   * 
   * @param left Left value
   * @param right Right value
   * @return Merged result
   */
  T merge(T left, T right);
}