001/*
002 * Copyright (c) 2016-2017 Chris K Wensel <chris@wensel.net>. All Rights Reserved.
003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
004 *
005 * Project and contact information: http://www.cascading.org/
006 *
007 * This file is part of the Cascading project.
008 *
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 *
013 *     http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 */
021
022package cascading.tuple;
023
024import java.io.Closeable;
025import java.util.Iterator;
026
027/**
028 * Class TupleEntryIterator provides an efficient Iterator for returning {@link TupleEntry} elements in an
029 * underlying {@link Tuple} collection.
030 */
031public abstract class TupleEntryIterator implements Iterator<TupleEntry>, Closeable
032  {
033  /** Field entry */
034  final TupleEntry entry;
035
036  /**
037   * Constructor TupleEntryIterator creates a new TupleEntryIterator instance.
038   *
039   * @param fields of type Fields
040   */
041  public TupleEntryIterator( Fields fields )
042    {
043    this.entry = new TupleEntry( fields, Tuple.size( fields.size() ) );
044    }
045
046  /**
047   * Method getFields returns the fields of this TupleEntryIterator object.
048   *
049   * @return the fields (type Fields) of this TupleEntryIterator object.
050   */
051  public Fields getFields()
052    {
053    return entry.getFields();
054    }
055
056  /**
057   * Method getTupleEntry returns the entry of this TupleEntryIterator object.
058   * <p>
059   * Since {@link TupleEntry} and the underlying {@link Tuple} instances are re-used, you must make a copy if you wish
060   * to store the instances in a Collection for later use.
061   *
062   * @return the entry (type TupleEntry) of this TupleEntryIterator object.
063   */
064  public TupleEntry getTupleEntry()
065    {
066    return entry;
067    }
068  }