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.tuple;
022    
023    import java.io.Closeable;
024    import java.util.Iterator;
025    
026    /**
027     * Class TupleEntryIterator provides an efficient Iterator for returning {@link TupleEntry} elements in an
028     * underlying {@link Tuple} collection.
029     */
030    public abstract class TupleEntryIterator implements Iterator<TupleEntry>, Closeable
031      {
032      /** Field entry */
033      final TupleEntry entry;
034    
035      /**
036       * Constructor TupleEntryIterator creates a new TupleEntryIterator instance.
037       *
038       * @param fields of type Fields
039       */
040      public TupleEntryIterator( Fields fields )
041        {
042        this.entry = new TupleEntry( fields, Tuple.size( fields.size() ) );
043        }
044    
045      /**
046       * Method getFields returns the fields of this TupleEntryIterator object.
047       *
048       * @return the fields (type Fields) of this TupleEntryIterator object.
049       */
050      public Fields getFields()
051        {
052        return entry.getFields();
053        }
054    
055      /**
056       * Method getTupleEntry returns the entry of this TupleEntryIterator object.
057       * <p/>
058       * Since {@link TupleEntry} and the underlying {@link Tuple} instances are re-used, you must make a copy if you wish
059       * to store the instances in a Collection for later use.
060       *
061       * @return the entry (type TupleEntry) of this TupleEntryIterator object.
062       */
063      public TupleEntry getTupleEntry()
064        {
065        return entry;
066        }
067      }