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.joiner; 023 024import java.util.Iterator; 025 026import cascading.tuple.Fields; 027import cascading.tuple.Tuple; 028 029/** 030 * Class BufferJoiner notifies the Cascading planner that the next {@link cascading.operation.Buffer} instance 031 * will implement a custom join strategy. 032 * <p> 033 * Internally this class simply returns {@link Fields#NONE} from {@link #getFieldDeclaration()} as a flag to 034 * the planner. 035 */ 036public class BufferJoin extends BaseJoiner 037 { 038 public BufferJoin() 039 { 040 super( Fields.NONE ); 041 } 042 043 @Override 044 public Iterator<Tuple> getIterator( JoinerClosure closure ) 045 { 046 return null; 047 } 048 049 @Override 050 public int numJoins() 051 { 052 return -1; 053 } 054 }