001    /*
002     * Copyright (c) 2007-2015 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.tap.partition;
022    
023    import java.util.Iterator;
024    
025    import cascading.tap.TapException;
026    import cascading.tuple.Fields;
027    import cascading.tuple.Tuple;
028    import cascading.tuple.TupleEntry;
029    import cascading.tuple.TupleEntrySchemeIterator;
030    import cascading.tuple.util.TupleViews;
031    
032    /**
033     *
034     */
035    public 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      }