Single Item Enumeration : Enumerator « Collections Data Structure « Java

Single Item Enumeration

 * The utillib library.
 * More information is available at
 * Copyright (C) 2002 Alexander Maryanovsky.
 * All rights reserved.
 * The utillib library is free software; you can redistribute
 * it and/or modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * The utillib library is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License
 * along with utillib library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import java.util.Enumeration;
import java.util.NoSuchElementException;

 * An implementation of the Enumeration interface which enumerates a single
 * item. Note: This class is not thread safe.

public class SingleItemEnumeration implements Enumeration{

   * The sole item.

  private Object item;

   * Becomes true when we've returned the sole item.

  private boolean done = false;

   * Creates a new SingleItemEnumeration which enumerates the specified item.

  public SingleItemEnumeration(Object item){
    this.item = item;

   * Returns the sole item or throws a <code>NoSuchElementException</code>.

  public Object nextElement(){
    if (!hasMoreElements())
      throw new NoSuchElementException();
    done = true;

    Object item = this.item;
    this.item = null; // We don't want to hold a reference to it any longer than we need.
    return item;

   * Returns true if there are more elements in the enumeration.

  public boolean hasMoreElements(){
    return !done;



Related examples in the same category

1.Wrapping an Iterator around an Enumeration
2.A GOF Adapter to make instances of old Enumeration interface behave like new Iterator interface
3.A more robust enumeration systemA more robust enumeration system
4.ListOfFiles implements Enumeration
5.Treat an Enumeration as an Iterable
6.Support for breadth-first enumerating.
7.Empty Enumeration
8.Enumeration interface which enumerates the items of an arrayEnumeration interface which enumerates the items of an array
9.Filtering Enumeration
10.An enumeration that iterates over an array.An enumeration that iterates over an array.
11.Concatenates the content of two enumerations into one.
12.Removes all nulls from the input enumeration.
13.Filters some elements out from the input enumeration.
14.For each element of the input enumeration asks the Processor to provide a replacement