| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 1999 The Apache Software Foundation. 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 end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * 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 APACHE SOFTWARE FOUNDATION OR |
| * ITS 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 Apache Software Foundation and was |
| * originally based on software copyright (c) 1999, Lotus |
| * Development Corporation., http://www.lotus.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.xpath.objects; |
| |
| //import org.w3c.dom.traversal.NodeIterator; |
| //import org.w3c.dom.DocumentFragment; |
| |
| import org.apache.xml.dtm.DTM; |
| import org.apache.xml.dtm.DTMIterator; |
| |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.NodeSetDTM; |
| |
| /** |
| * <meta name="usage" content="general"/> |
| * This class represents an XPath null object, and is capable of |
| * converting the null to other types, such as a string. |
| */ |
| public class XNull extends XNodeSet |
| { |
| |
| /** |
| * Create an XObject. |
| */ |
| public XNull() |
| { |
| super(); |
| } |
| |
| /** |
| * Tell what kind of class this is. |
| * |
| * @return type CLASS_NULL |
| */ |
| public int getType() |
| { |
| return CLASS_NULL; |
| } |
| |
| /** |
| * Given a request type, return the equivalent string. |
| * For diagnostic purposes. |
| * |
| * @return type string "#CLASS_NULL" |
| */ |
| public String getTypeString() |
| { |
| return "#CLASS_NULL"; |
| } |
| |
| /** |
| * Cast result object to a number. |
| * |
| * @return 0.0 |
| */ |
| |
| public double num() |
| { |
| return 0.0; |
| } |
| |
| /** |
| * Cast result object to a boolean. |
| * |
| * @return false |
| */ |
| public boolean bool() |
| { |
| return false; |
| } |
| |
| /** |
| * Cast result object to a string. |
| * |
| * @return empty string "" |
| */ |
| public String str() |
| { |
| return ""; |
| } |
| |
| /** |
| * Cast result object to a result tree fragment. |
| * |
| * @param support XPath context to use for the conversion |
| * |
| * @return The object as a result tree fragment. |
| */ |
| public int rtf(XPathContext support) |
| { |
| // DTM frag = support.createDocumentFragment(); |
| // %REVIEW% |
| return DTM.NULL; |
| } |
| |
| // /** |
| // * Cast result object to a nodelist. |
| // * |
| // * @return null |
| // */ |
| // public DTMIterator iter() |
| // { |
| // return null; |
| // } |
| |
| /** |
| * Tell if two objects are functionally equal. |
| * |
| * @param obj2 Object to compare this to |
| * |
| * @return True if the given object is of type CLASS_NULL |
| */ |
| public boolean equals(XObject obj2) |
| { |
| return obj2.getType() == CLASS_NULL; |
| } |
| } |