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.io.Closeable;
024import 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 */
030public 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  }