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.tap.partition;
022
023import java.util.Iterator;
024
025import cascading.tap.TapException;
026import cascading.tuple.Fields;
027import cascading.tuple.Tuple;
028import cascading.tuple.TupleEntry;
029import cascading.tuple.TupleEntrySchemeIterator;
030import cascading.tuple.util.TupleViews;
031
032/**
033 *
034 */
035public class PartitionTupleEntryIterator implements Iterator<Tuple>
036  {
037  private final TupleEntrySchemeIterator childIterator;
038  private final Tuple base;
039  private final Tuple view;
040
041  public PartitionTupleEntryIterator( Fields sourceFields, Partition partition, String parentIdentifier, String childIdentifier, TupleEntrySchemeIterator schemeIterator )
042    {
043    this.childIterator = schemeIterator;
044
045    TupleEntry partitionEntry = new TupleEntry( partition.getPartitionFields(), Tuple.size( partition.getPartitionFields().size() ) );
046
047    try
048      {
049      partition.toTuple( childIdentifier.substring( parentIdentifier.length() + 1 ), partitionEntry );
050      }
051    catch( Exception exception )
052      {
053      throw new TapException( "unable to parse partition given parent: " + parentIdentifier + " and child: " + childIdentifier );
054      }
055
056    base = TupleViews.createOverride( sourceFields, partitionEntry.getFields() );
057
058    TupleViews.reset( base, Tuple.size( sourceFields.size() ), partitionEntry.getTuple() );
059
060    view = TupleViews.createOverride( sourceFields, childIterator.getFields() );
061    }
062
063  @Override
064  public boolean hasNext()
065    {
066    return childIterator.hasNext();
067    }
068
069  @Override
070  public Tuple next()
071    {
072    Tuple tuple = childIterator.next().getTuple();
073    TupleViews.reset( view, base, tuple );
074
075    return view;
076    }
077
078  @Override
079  public void remove()
080    {
081    childIterator.remove();
082    }
083  }