org.apache.xpath.objects.XNull Maven / Gradle / Ivy
/*
* 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.
*/
/*
* $Id: XNull.java 468655 2006-10-28 07:12:06Z minchau $
*/
package org.apache.xpath.objects;
import org.apache.xml.dtm.DTM;
import org.apache.xpath.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;
}
}