/* * (c) Copyright 2010 Epimorphics Ltd. * All rights reserved. * [See end of file] */ package org.openjena.atlas.iterator; import java.util.Iterator ; import java.util.Stack ; public class PushbackIterator implements Iterator { // Java6 : Deque items = new ArrayDeque(); private Stack items = new Stack() ; private Iterator iter ; public PushbackIterator(Iterator iter) { if ( iter == null ) throw new IllegalArgumentException("Wrapped iterator can't be null") ; this.iter = iter ; } public void pushback(T item) { items.push(item) ; } public boolean hasNext() { if ( !items.empty() ) return true ; return iter.hasNext() ; } public T next() { if ( !items.empty() ) return items.pop() ; return iter.next() ; } public void remove() { // Need to track if last next() was from the stack or not. throw new UnsupportedOperationException() ; } } /* * (c) Copyright 2010 Epimorphics Ltd. * 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 following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 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 AUTHOR 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. */