    001    /*
    002     * Copyright (c) 2007-2014 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
    021    package cascading.pipe.joiner;
    022
    023    import java.util.Iterator;
    024
    025    import cascading.tuple.Fields;
    026    import 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     */
    035    public 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      }