    001/*
    002 * Copyright (c) 2007-2016 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
    021package cascading.tuple;
    022
    023import java.util.Iterator;
    024import java.util.LinkedList;
    025
    026/**
    027 * TupleEntryCollector is a convenience class for managing a list of tuples. More specifically it can simultaneously
    028 * append and modify in place elements of the list through the use of a ListIterator.
    029 */
    030public class TupleListCollector extends TupleEntryCollector implements Iterable<Tuple>
    031  {
    032  /** Field tuples */
    033  private final LinkedList<Tuple> tuples = new LinkedList<Tuple>();
    034  /** Field copyTupleOnCollect */
    035  private boolean copyTupleOnCollect = false;
    036
    037  /**
    038   * Constructor TupleEntryCollector creates a new TupleEntryCollector instance.
    039   *
    040   * @param fields of type Fields
    041   * @param tuple  of type Tuple...
    042   */
    043  public TupleListCollector( Fields fields, Tuple... tuple )
    044    {
    045    super( fields );
    046
    047    collect( tuple );
    048    }
    049
    050  /**
    051   * Constructor TupleListCollector creates a new TupleListCollector instance.
    052   * <p/>
    053   * Set copyTupleOnCollect to {@code true} if a new Tuple instance should be stored in the
    054   * underlying list.
    055   *
    056   * @param fields             of type Fields
    057   * @param copyTupleOnCollect of type boolean
    058   */
    059  public TupleListCollector( Fields fields, boolean copyTupleOnCollect )
    060    {
    061    super( fields );
    062    this.copyTupleOnCollect = copyTupleOnCollect;
    063    }
    064
    065  /**
    066   * Method collect adds every given Tuple instance. It tests for and ignores empty Tuples.
    067   *
    068   * @param tuples of type Tuple
    069   */
    070  private void collect( Tuple... tuples )
    071    {
    072    for( Tuple tuple : tuples )
    073      add( tuple );
    074    }
    075
    076  protected void collect( TupleEntry tupleEntry )
    077    {
    078    if( copyTupleOnCollect )
    079      tuples.add( tupleEntry.getTupleCopy() );
    080    else
    081      tuples.add( tupleEntry.getTuple() );
    082    }
    083
    084  /**
    085   * Method isEmpty returns true if this collection is empty.
    086   *
    087   * @return the empty (type boolean) of this TupleCollector object.
    088   */
    089  public boolean isEmpty()
    090    {
    091    return tuples.isEmpty();
    092    }
    093
    094  /** Method clear clears all Tuple instances from this instance. */
    095  public void clear()
    096    {
    097    tuples.clear();
    098    }
    099
    100  /**
    101   * Returns the size of this collection.
    102   *
    103   * @return int
    104   */
    105  public int size()
    106    {
    107    return tuples.size();
    108    }
    109
    110  /**
    111   * Method iterator returns an iterator for this collection.
    112   *
    113   * @return Iterator<Tuple>
    114   */
    115  public Iterator<Tuple> iterator()
    116    {
    117    return tuples.iterator();
    118    }
    119
    120  /**
    121   * Method entryIterator return a TupleEntry iterator for this collection.
    122   * </p>
    123   * Note the same TupleEntry will be returned on each next() call.
    124   *
    125   * @return Iterator<TupleEntry>
    126   */
    127  public Iterator<TupleEntry> entryIterator()
    128    {
    129    return new TupleEntryChainIterator( tupleEntry.getFields(), tuples.iterator() );
    130    }
    131  }