    001/*
    002 * Copyright (c) 2007-2017 Xplenty, 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.tuple;
    022
    023import java.util.Iterator;
    024
    025import cascading.tuple.util.Resettable;
    026
    027/**
    028 * TupleChainIterator chains the given Iterators into a single Iterator.
    029 * <p/>
    030 * As one iterator is completed, it will be closed and a new one will start.
    031 */
    032public class TupleChainIterable implements Iterable<Tuple>, Resettable<Iterable<Tuple>>
    033  {
    034  /** Field iterator */
    035  Iterable<Tuple>[] iterables;
    036
    037  public TupleChainIterable( Iterable<Tuple> first, Iterable<Tuple>... iterables )
    038    {
    039    Iterable<Tuple>[] initial;
    040
    041    if( first instanceof TupleChainIterable )
    042      initial = ( (TupleChainIterable) first ).iterables;
    043    else
    044      initial = new Iterable[]{first};
    045
    046    this.iterables = new Iterable[ initial.length + iterables.length ];
    047
    048    System.arraycopy( initial, 0, this.iterables, 0, initial.length );
    049    System.arraycopy( iterables, 0, this.iterables, initial.length, iterables.length );
    050    }
    051
    052
    053  @Override
    054  public Iterator<Tuple> iterator()
    055    {
    056    Iterator<Tuple>[] iterators = new Iterator[ iterables.length ];
    057
    058    for( int i = 0; i < iterables.length; i++ )
    059      iterators[ i ] = iterables[ i ].iterator();
    060
    061    return new TupleChainIterator( iterators );
    062    }
    063
    064  @Override
    065  public void reset( Iterable<Tuple>... iterables )
    066    {
    067    this.iterables = iterables;
    068    }
    069  }