org.apache.xpath.objects
Class XNumber

java.lang.Object
  org.apache.xpath.Expression
      org.apache.xpath.objects.XObject
          org.apache.xpath.objects.XNumber

All Implemented Interfaces:

Cloneable, ExpressionNode, Serializable, javax.xml.transform.SourceLocator, XPathVisitable

public class XNumber

extends XObject

This class represents an XPath number, and is capable of converting the number to other types, such as a string.

See Also:

Serialized Form

Field Summary

(package private) double

m_val Value of the XNumber object.

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, m_obj

Fields inherited from class org.apache.xpath.Expression

Constructor Summary

XNumber(double d)
Construct a XNodeSet object.

XNumber(Number num)
Construct a XNodeSet object.

Method Summary

boolean	bool() Cast result object to a boolean.
void	callVisitors(ExpressionOwner owner, XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.
boolean	equals(XObject obj2) Tell if two objects are functionally equal.
int	getType() Tell that this is a CLASS_NUMBER.
String	getTypeString() Given a request type, return the equivalent string.
boolean	isStableNumber() Tell if this expression returns a stable number that will not change during iterations within the expression.
double	num() Cast result object to a number.
double	num(XPathContext xctxt) Evaluate expression to a number.
Object	object() Return a java object that's closest to the representation that should be handed to an extension.
String	str() Cast result object to a string.
private static String	zeros(int n) Return a string of '0' of the given length

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

allowDetachToRelease, appendToFsb, boolWithSideEffects, castToType, create, create, deepEquals, destruct, detach, dispatchCharactersEvents, error, error, execute, fixupVariables, getFresh, greaterThan, greaterThanOrEqual, iter, lessThan, lessThanOrEqual, mutableNodeset, nodelist, nodeset, notEquals, numWithSideEffects, reset, rtf, rtf, rtree, rtree, toString, xstr

Methods inherited from class org.apache.xpath.Expression

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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

m_val

double m_val

Value of the XNumber object.

Constructor Detail

XNumber

public XNumber(double d)

Construct a XNodeSet object.

Parameters:

d - Value of the object

XNumber

public XNumber(Number num)

Construct a XNodeSet object.

Method Detail

getType

public int getType()

Tell that this is a CLASS_NUMBER.

Overrides:

getType in class XObject

Returns:

node type CLASS_NUMBER

getTypeString

public String getTypeString()

Given a request type, return the equivalent string. For diagnostic purposes.

Overrides:

getTypeString in class XObject

Returns:

type string "#NUMBER"

num

public double num()

Cast result object to a number.

Overrides:

num in class XObject

Returns:

the value of the XNumber object

num

public double num(XPathContext xctxt)
           throws javax.xml.transform.TransformerException

Evaluate expression to a number.

Overrides:

num in class Expression

Parameters:

xctxt - The XPath runtime context.

Returns:

0.0

Throws:

javax.xml.transform.TransformerException

bool

public boolean bool()

Cast result object to a boolean.

Overrides:

bool in class XObject

Returns:

false if the value is NaN or equal to 0.0

str

public String str()

Cast result object to a string.

Overrides:

str in class XObject

Returns:

"NaN" if the number is NaN, Infinity or -Infinity if the number is infinite or the string value of the number.

zeros

private static String zeros(int n)

Return a string of '0' of the given length

Parameters:

n - Length of the string to be returned

Returns:

a string of '0' with the given length

object

public Object object()

Return a java object that's closest to the representation that should be handed to an extension.

Overrides:

object in class XObject

Returns:

The value of this XNumber as a Double object

equals

public boolean equals(XObject obj2)

Tell if two objects are functionally equal.

Overrides:

equals in class XObject

Parameters:

obj2 - Object to compare this to

Returns:

true if the two objects are equal

Throws:

javax.xml.transform.TransformerException

isStableNumber

public boolean isStableNumber()

Tell if this expression returns a stable number that will not change during iterations within the expression. This is used to determine if a proximity position predicate can indicate that no more searching has to occur.

Overrides:

isStableNumber in class Expression

Returns:

true if the expression represents a stable number.

callVisitors

public void callVisitors(ExpressionOwner owner,
                         XPathVisitor visitor)

Description copied from interface: XPathVisitable

This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.

Specified by:

callVisitors in interface XPathVisitable

Overrides:

callVisitors in class XObject

See Also:

XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)