| /* |
| * reserved comment block |
| * DO NOT REMOVE OR ALTER! |
| */ |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.sun.org.apache.xpath.internal.objects; |
| |
| import com.sun.org.apache.xml.internal.dtm.DTM; |
| import com.sun.org.apache.xpath.internal.XPathContext; |
| |
| /** |
| * This class represents an XPath null object, and is capable of |
| * converting the null to other types, such as a string. |
| * @xsl.usage general |
| */ |
| public class XNull extends XNodeSet |
| { |
| static final long serialVersionUID = -6841683711458983005L; |
| |
| /** |
| * 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; |
| } |
| } |