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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
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 * 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
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 *      http://www.apache.org/licenses/LICENSE-2.0
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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.usagegeneral
/** * 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.
/** * Create an XObject. */
public XNull() { super(); }
Tell what kind of class this is.
Returns:type CLASS_NULL
/** * 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.
Returns:type string "#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.
Returns:0.0
/** * Cast result object to a number. * * @return 0.0 */
public double num() { return 0.0; }
Cast result object to a boolean.
Returns:false
/** * Cast result object to a boolean. * * @return false */
public boolean bool() { return false; }
Cast result object to a string.
Returns:empty string ""
/** * Cast result object to a string. * * @return empty string "" */
public String str() { return ""; }
Cast result object to a result tree fragment.
Params:
  • support – XPath context to use for the conversion
Returns:The object as a result tree fragment.
/** * 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.
Params:
  • obj2 – Object to compare this to
Returns:True if the given object is of type CLASS_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; } }