    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  }