content: /* ========================================================================
   * JCommon : a free general purpose class library for the Java(tm) platform
   * ========================================================================
   *
   * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
   * 
   * Project Info:  http://www.jfree.org/jcommon/index.html
   *
   * This 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 2.1 of the License, or 
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but 
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
   * USA.  
   *
   * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
   * in the United States and other countries.]
   * 
   * ---------------------
   * ReadOnlyIterator.java
   * ---------------------
   * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
   *
   * Original Author:  Thomas Morgner;
   * Contributor(s):   -;
   *
   * $Id: ReadOnlyIterator.java,v 1.2 2005/10/18 13:24:19 mungady Exp $
   *
   * Changes
   * -------------------------
   * 18-Jul-2003 : Initial version
   *
   */
  
  package org.jfree.util;
  
  import java.util.Iterator;
  
  /**
   * Protects an given iterator by preventing calls to remove().
   *
   * @author Thomas Morgner
   */
  public class ReadOnlyIterator implements Iterator {
  
      /** The base iterator which we protect. */
      private Iterator base;
  
      /**
       * Creates a new read-only iterator for the given iterator.
       *
       * @param it the iterator.
       */
      public ReadOnlyIterator(final Iterator it) {
          if (it == null) {
              throw new NullPointerException("Base iterator is null.");
          }
          this.base = it;
      }
  
      /**
       * Returns <tt>true</tt> if the iteration has more elements. (In other
       * words, returns <tt>true</tt> if <tt>next</tt> would return an element
       * rather than throwing an exception.)
       *
       * @return <tt>true</tt> if the iterator has more elements.
       */
      public boolean hasNext() {
          return this.base.hasNext();
      }
  
      /**
       * Returns the next element in the iteration.
       * Throws NoSuchElementException when iteration has no more elements.
       * 
       * @return the next element in the iteration.
       */
      public Object next() {
          return this.base.next();
      }
  
      /**
       * Throws <code>UnsupportedOperationException</code>.
       */
      public void remove() {
          throw new UnsupportedOperationException();
      }
  }
  