Linked Iterator : Iterator « Collections Data Structure « Java






Linked Iterator

    
/*
 * $Header: /cvsroot/jaxen/jaxen/src/java/main/org/jaxen/util/LinkedIterator.java,v 1.2 2002/04/26 17:17:36 jstrachan Exp $
 * $Revision: 1.2 $
 * $Date: 2002/04/26 17:17:36 $
 *
 * 
 *
 * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions, and the disclaimer that follows 
 *    these conditions in the documentation and/or other materials 
 *    provided with the distribution.
 *
 * 3. The name "Jaxen" must not be used to endorse or promote products
 *    derived from this software without prior written permission.  For
 *    written permission, please contact license@jaxen.org.
 * 
 * 4. Products derived from this software may not be called "Jaxen", nor
 *    may "Jaxen" appear in their name, without prior written permission
 *    from the Jaxen Project Management (pm@jaxen.org).
 * 
 * In addition, we request (but do not require) that you include in the 
 * end-user documentation provided with the redistribution and/or in the 
 * software itself an acknowledgement equivalent to the following:
 *     "This product includes software developed by the
 *      Jaxen Project (http://www.jaxen.org/)."
 * Alternatively, the acknowledgment may be graphical using the logos 
 * available at http://www.jaxen.org/
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * 
 * This software consists of voluntary contributions made by many 
 * individuals on behalf of the Jaxen Project and was originally 
 * created by bob mcwhirter <bob@werken.com> and 
 * James Strachan <jstrachan@apache.org>.  For more information on the 
 * Jaxen Project, please see <http://www.jaxen.org/>.
 * 
 * $Id: LinkedIterator.java,v 1.2 2002/04/26 17:17:36 jstrachan Exp $
 */



import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.List;
import java.util.ArrayList;

public class LinkedIterator implements Iterator
{
    private List iterators;
    private int  cur;

    public LinkedIterator()
    {
        this.iterators = new ArrayList();
        this.cur       = 0;
    }

    public void addIterator(Iterator i)
    {
        this.iterators.add( i );
    }

    public boolean hasNext()
    {
        boolean has = false;

        if ( this.cur < this.iterators.size() )
        {
            has = ((Iterator)this.iterators.get( this.cur )).hasNext();

            if ( ! has
                 &&
                 this.cur < this.iterators.size() )
            {
                ++this.cur;
                has = hasNext();
            }
        }
        else
        {
            has = false;
        }

        return has;
    }

    public Object next()
    {
        if ( ! hasNext() )
        {
            throw new NoSuchElementException();
        }

        return ((Iterator)this.iterators.get( this.cur )).next();
    }

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

   
    
    
    
  








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