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  }