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1: /* ======================================================================== 2: * JCommon : a free general purpose class library for the Java(tm) platform 3: * ======================================================================== 4: * 5: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors. 6: * 7: * Project Info: http://www.jfree.org/jcommon/index.html 8: * 9: * This library is free software; you can redistribute it and/or modify it 10: * under the terms of the GNU Lesser General Public License as published by 11: * the Free Software Foundation; either version 2.1 of the License, or 12: * (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but 15: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 17: * License for more details. 18: * 19: * You should have received a copy of the GNU Lesser General Public 20: * License along with this library; if not, write to the Free Software 21: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 22: * USA. 23: * 24: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 25: * in the United States and other countries.] 26: * 27: * --------------------- 28: * ReadOnlyIterator.java 29: * --------------------- 30: * (C)opyright 2003, 2004, by Thomas Morgner and Contributors. 31: * 32: * Original Author: Thomas Morgner; 33: * Contributor(s): -; 34: * 35: * $Id: ReadOnlyIterator.java,v 1.2 2005/10/18 13:24:19 mungady Exp $ 36: * 37: * Changes 38: * ------------------------- 39: * 18-Jul-2003 : Initial version 40: * 41: */ 42: 43: package org.jfree.util; 44: 45: import java.util.Iterator; 46: 47: /** 48: * Protects an given iterator by preventing calls to remove(). 49: * 50: * @author Thomas Morgner 51: */ 52: public class ReadOnlyIterator implements Iterator { 53: 54: /** The base iterator which we protect. */ 55: private Iterator base; 56: 57: /** 58: * Creates a new read-only iterator for the given iterator. 59: * 60: * @param it the iterator. 61: */ 62: public ReadOnlyIterator(final Iterator it) { 63: if (it == null) { 64: throw new NullPointerException("Base iterator is null."); 65: } 66: this.base = it; 67: } 68: 69: /** 70: * Returns <tt>true</tt> if the iteration has more elements. (In other 71: * words, returns <tt>true</tt> if <tt>next</tt> would return an element 72: * rather than throwing an exception.) 73: * 74: * @return <tt>true</tt> if the iterator has more elements. 75: */ 76: public boolean hasNext() { 77: return this.base.hasNext(); 78: } 79: 80: /** 81: * Returns the next element in the iteration. 82: * Throws NoSuchElementException when iteration has no more elements. 83: * 84: * @return the next element in the iteration. 85: */ 86: public Object next() { 87: return this.base.next(); 88: } 89: 90: /** 91: * Throws <code>UnsupportedOperationException</code>. 92: */ 93: public void remove() { 94: throw new UnsupportedOperationException(); 95: } 96: }