A singleton null object Iterator implementation.

        

import java.util.Iterator;
import java.util.NoSuchElementException;

/*********************************************************************
 * A singleton null object Iterator implementation.
 * 
 * @version 2003-05-12
 * @since 2003-05-10
 * @author <a href="http://www.CroftSoft.com/">David Wallace Croft</a>
 *********************************************************************/

public final class NullIterator implements Iterator
// ////////////////////////////////////////////////////////////////////
// ////////////////////////////////////////////////////////////////////
{

  public static final NullIterator INSTANCE = new NullIterator();

  // ////////////////////////////////////////////////////////////////////
  // ////////////////////////////////////////////////////////////////////

  public boolean hasNext() {
    return false;
  }

  public Object next() {
    throw new NoSuchElementException();
  }

  public void remove() {
    throw new UnsupportedOperationException();
  }

  // ////////////////////////////////////////////////////////////////////
  // ////////////////////////////////////////////////////////////////////

  private NullIterator() {
  }

  // ////////////////////////////////////////////////////////////////////
  // ////////////////////////////////////////////////////////////////////
}

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A singleton null object Iterator implementation. : Iterator « Collections Data Structure « Java

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