001/* 002 * Copyright (c) 2016-2017 Chris K Wensel <chris@wensel.net>. All Rights Reserved. 003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved. 004 * 005 * Project and contact information: http://www.cascading.org/ 006 * 007 * This file is part of the Cascading project. 008 * 009 * Licensed under the Apache License, Version 2.0 (the "License"); 010 * you may not use this file except in compliance with the License. 011 * You may obtain a copy of the License at 012 * 013 * http://www.apache.org/licenses/LICENSE-2.0 014 * 015 * Unless required by applicable law or agreed to in writing, software 016 * distributed under the License is distributed on an "AS IS" BASIS, 017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 018 * See the License for the specific language governing permissions and 019 * limitations under the License. 020 */ 021 022package cascading.pipe; 023 024import java.beans.ConstructorProperties; 025 026/** 027 * The Merge Pipe allows for multiple branches, with the same fields to be spliced back into a single stream. 028 * <p> 029 * The behavior is similar to the {@link GroupBy} merging features, but Merge does not perform any grouping or 030 * sorting on keys. Thus, when using a MapReduce platform, no Reducer is required. 031 * <p> 032 * Merge is non-blocking and performs no processing. Any number of branches and merges may be performed in a 033 * {@link cascading.flow.Flow} without triggering any additional MapReduce jobs on the Hadoop platform. 034 * <p> 035 * Unlike {@link HashJoin}, no preference need be made for left-hand or right-hand sided-ness of streams in relation 036 * to their sizes. 037 * 038 * @see GroupBy 039 */ 040public class Merge extends Splice 041 { 042 /** 043 * Constructor Merge creates a new Merge instance. 044 * 045 * @param pipes 046 */ 047 @ConstructorProperties({"pipes"}) 048 public Merge( Pipe... pipes ) 049 { 050 super( null, pipes ); 051 } 052 053 /** 054 * Constructor Merge creates a new Merge instance. 055 * 056 * @param name 057 * @param pipes 058 */ 059 @ConstructorProperties({"name", "pipes"}) 060 public Merge( String name, Pipe... pipes ) 061 { 062 super( name, pipes ); 063 } 064 }