001/* 002 * Copyright (c) 2007-2016 Concurrent, Inc. All Rights Reserved. 003 * 004 * Project and contact information: http://www.cascading.org/ 005 * 006 * This file is part of the Cascading project. 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020 021package cascading.pipe.joiner; 022 023import java.util.Iterator; 024 025import cascading.tuple.Fields; 026import cascading.tuple.Tuple; 027 028/** 029 * Class BufferJoiner notifies the Cascading planner that the next {@link cascading.operation.Buffer} instance 030 * will implement a custom join strategy. 031 * <p/> 032 * Internally this class simply returns {@link Fields#NONE} from {@link #getFieldDeclaration()} as a flag to 033 * the planner. 034 */ 035public class BufferJoin extends BaseJoiner 036 { 037 public BufferJoin() 038 { 039 super( Fields.NONE ); 040 } 041 042 @Override 043 public Iterator<Tuple> getIterator( JoinerClosure closure ) 044 { 045 return null; 046 } 047 048 @Override 049 public int numJoins() 050 { 051 return -1; 052 } 053 }