org.apache.xpath.objects

Class XNull

Implemented Interfaces:
Cloneable, DTMIterator, ExpressionNode, PathComponent, Serializable, SourceLocator, XPathVisitable

public class XNull
extends XNodeSet

This class represents an XPath null object, and is capable of converting the null to other types, such as a string.
See Also:
Serialized Form

Field Summary

Fields inherited from class org.apache.xpath.objects.XObject

CLASS_BOOLEAN, CLASS_NODESET, CLASS_NULL, CLASS_NUMBER, CLASS_RTREEFRAG, CLASS_STRING, CLASS_UNKNOWN, CLASS_UNRESOLVEDVARIABLE

Fields inherited from interface org.apache.xml.dtm.DTMIterator

FILTER_ACCEPT, FILTER_REJECT, FILTER_SKIP

Constructor Summary

XNull()
Create an XObject.

Method Summary

boolean
bool()
Cast result object to a boolean.
boolean
equals(XObject obj2)
Tell if two objects are functionally equal.
int
getType()
Tell what kind of class this is.
String
getTypeString()
Given a request type, return the equivalent string.
double
num()
Cast result object to a number.
int
rtf(XPathContext support)
Cast result object to a result tree fragment.
String
str()
Cast result object to a string.

Methods inherited from class org.apache.xpath.objects.XNodeSet

appendToFsb, bool, boolWithSideEffects, compare, dispatchCharactersEvents, equals, getFresh, getNumberFromNode, getStringFromNode, getType, getTypeString, greaterThan, greaterThanOrEqual, iter, iterRaw, lessThan, lessThanOrEqual, mutableNodeset, nodelist, nodeset, notEquals, num, numWithSideEffects, object, release, str, xstr

Methods inherited from class org.apache.xpath.axes.NodeSequence

allowDetachToRelease, clone, cloneWithReset, detach, fixupVariables, getAnalysisBits, getAxis, getContainedIter, getCurrentNode, getCurrentPos, getDTM, getDTMManager, getExpandEntityReferences, getLength, getRoot, getWhatToShow, hasCache, isDocOrdered, isFresh, isMutable, item, nextNode, previousNode, reset, runTo, setCurrentPos, setItem, setIter, setRoot, setShouldCacheNodes

Methods inherited from class org.apache.xpath.objects.XObject

allowDetachToRelease, appendToFsb, bool, boolWithSideEffects, callVisitors, castToType, create, create, deepEquals, destruct, detach, dispatchCharactersEvents, equals, execute, fixupVariables, getFresh, getType, getTypeString, greaterThan, greaterThanOrEqual, iter, lessThan, lessThanOrEqual, mutableNodeset, nodelist, nodeset, notEquals, num, numWithSideEffects, object, reset, rtf, rtf, rtree, rtree, str, toString, xstr

Methods inherited from class org.apache.xpath.Expression

asIterator, asIteratorRaw, asNode, assertion, bool, canTraverseOutsideSubtree, deepEquals, error, execute, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, fixupVariables, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isStableNumber, num, warn, xstr

Constructor Details

XNull

public XNull()
Create an XObject.

Method Details

bool

public boolean bool()
Cast result object to a boolean.
Overrides:
bool in interface XNodeSet
Returns:
false

equals

public boolean equals(XObject obj2)
Tell if two objects are functionally equal.
Overrides:
equals in interface XNodeSet
Parameters:
obj2 - Object to compare this to
Returns:
True if the given object is of type CLASS_NULL

getType

public int getType()
Tell what kind of class this is.
Overrides:
getType in interface XNodeSet
Returns:
type CLASS_NULL

getTypeString

public String getTypeString()
Given a request type, return the equivalent string. For diagnostic purposes.
Overrides:
getTypeString in interface XNodeSet
Returns:
type string "#CLASS_NULL"

num

public double num()
Cast result object to a number.
Overrides:
num in interface XNodeSet
Returns:
0.0

rtf

public int rtf(XPathContext support)
Cast result object to a result tree fragment.
Overrides:
rtf in interface XObject
Parameters:
support - XPath context to use for the conversion
Returns:
The object as a result tree fragment.

str

public String str()
Cast result object to a string.
Overrides:
str in interface XNodeSet
Returns:
empty string ""

Copyright © 2006 Apache XML Project. All Rights Reserved.