com.novell.xml.xpath
Class NumberValue

java.lang.Object
  com.novell.xml.xpath.NumberValue

All Implemented Interfaces:

Comparable, Expression, ExpressionValue

public class NumberValue

extends Object

implements ExpressionValue, Expression, Comparable

Class to represent a number expression value

Field Summary

Fields inherited from interface com.novell.xml.xpath.ExpressionValue

BOOLEAN, EXTENDED, NATIVE, NODE_SET, NUMBER, STRING

Constructor Summary

NumberValue()
Construct a default NumberValue for use in casting.

NumberValue(double v)
Construct number value

Method Summary

void	castFrom(Object type) Convert from a different type of expression value to the NumberValue type This is used primarily for converting parameters for function calls.
int	compareTo(Object other) Compare this NumberValue to another Object.
static double	convertToNumber(String string) Convert a string to a number, using the rules for the XPath number() function.
void	dump(PrintWriter writer) Output a human-readable form for the value
void	dump(PrintWriter writer, int indent) Print the expression in a readable form for debugging.
boolean	equals(Object other) Compares this object against the specified Object.
ExpressionValue	evaluate(Node contextNode, ExpressionContext context) Evaluate the expression with repect to the passed context
static Class	getArgType() Return the Class object for objects of this type.
boolean	getBooleanValue() Return boolean value of expression value (will convert to boolean if value is not of type boolean)
Object	getNativeValue() return the underlying native value (java.lang.Boolean, java.lang.Double, etc.)
NodeSet	getNodeSetValue() Return node-set value of this ExpressionValue.
double	getNumberValue() Return numeric value of ExpressionValue.
Class	getResultType() Return the Class object describing the result type of the expression.
String	getStringValue() Return string value of this ExpressionValue.
static String	getStringValue(double value) Return string value of a double according to XPath spec
int	getValueType() Return type of expression value
int	hashCode() Returns a hash code for the value in this NumberValue.
boolean	isConstant() Return true if the expression is a constant value.
void	registerForReset(XPathResetRegistrar registrar) Register this expression or any subexpression that implements XPathResetCache with an object that wants to call resetCache()
String	toString() Provide a readable description for debugging.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

NumberValue

public NumberValue(double v)

Construct number value

Parameters:

v -

NumberValue

public NumberValue()

Construct a default NumberValue for use in casting.

Method Detail

getArgType

public static Class getArgType()

Return the Class object for objects of this type. This is used for FunctionSignature objects.

Returns:

The Class object corresponding to NumberValue

toString

public String toString()

Provide a readable description for debugging.

Returns:

String representation

convertToNumber

public static double convertToNumber(String string)

Convert a string to a number, using the rules for the XPath number() function. The string may consist of optional whitespace, an optional '-' character, a Number production, and optional whitespace.

Parameters:

string - The string to convert.

Returns:

The numeric value of the string, or NaN if string doesn't match rules for Number()

evaluate

public ExpressionValue evaluate(Node contextNode,
                                ExpressionContext context)

Evaluate the expression with repect to the passed context

Specified by:

evaluate in interface Expression

Parameters:

contextNode - context node for expression evaluation

context - expression context for expression evaluation

Returns:

result of evaluating expression

isConstant

public boolean isConstant()

Return true if the expression is a constant value.

Specified by:

isConstant in interface Expression

Returns:

True is expression is constant, false otherwise.

getResultType

public Class getResultType()

Return the Class object describing the result type of the expression.

Specified by:

getResultType in interface Expression

Returns:

A Class object.

registerForReset

public void registerForReset(XPathResetRegistrar registrar)

Register this expression or any subexpression that implements XPathResetCache with an object that wants to call resetCache()

Specified by:

registerForReset in interface Expression

dump

public void dump(PrintWriter writer,
                 int indent)

Print the expression in a readable form for debugging.

Specified by:

dump in interface Expression

Parameters:

writer - The output device.

indent - Number of tabs to indent the result.

getValueType

public int getValueType()

Return type of expression value

Specified by:

getValueType in interface ExpressionValue

Returns:

ExpressionValue.BOOLEAN, ExpressionValue.NUMBER, etc.

castFrom

public void castFrom(Object type)
              throws XPathConversionException

Convert from a different type of expression value to the NumberValue type This is used primarily for converting parameters for function calls.

Specified by:

castFrom in interface ExpressionValue

Parameters:

type - The object to convert from.

Throws:

XPathConversionException

getBooleanValue

public boolean getBooleanValue()
                        throws XPathConversionException

Return boolean value of expression value (will convert to boolean if value is not of type boolean)

Specified by:

getBooleanValue in interface ExpressionValue

Returns:

true or false

Throws:

XPathConversionException

getNumberValue

public double getNumberValue()
                      throws XPathConversionException

Return numeric value of ExpressionValue. Will convert to a number if value is not of NUMBER type

Specified by:

getNumberValue in interface ExpressionValue

Returns:

numeric value

Throws:

XPathConversionException

getStringValue

public String getStringValue()

Return string value of this ExpressionValue. Will convert to a string if underlying type is not string.

Specified by:

getStringValue in interface ExpressionValue

Returns:

String value of ExpressionValue

getStringValue

public static String getStringValue(double value)

Return string value of a double according to XPath spec

Returns:

String value of passed double

getNodeSetValue

public NodeSet getNodeSetValue()
                        throws XPathConversionException

Return node-set value of this ExpressionValue. Will NOT convert an underlying type to a node-set.

Specified by:

getNodeSetValue in interface ExpressionValue

Throws:

XPathConversionException

getNativeValue

public Object getNativeValue()

return the underlying native value (java.lang.Boolean, java.lang.Double, etc.)

Specified by:

getNativeValue in interface ExpressionValue

Returns:

The native java class that is the value

dump

public void dump(PrintWriter writer)

Output a human-readable form for the value

Specified by:

dump in interface ExpressionValue

Parameters:

writer - Output device

hashCode

public int hashCode()

Returns a hash code for the value in this NumberValue. Uses the same algorithm as java.lang.Double.

Returns:

a hash code value for this object.

equals

public boolean equals(Object other)

Compares this object against the specified Object. This will return true if the other Object is a NumberValue or a java.lang.Double and the long values resulting from java.lang.Double.doubleToLongBits() are identical.

Parameters:

other - Object to which to compare

Returns:

true if objects are equal

compareTo

public int compareTo(Object other)

Compare this NumberValue to another Object. If the other Object is a NumberValue or a java.lang.Double then the comparison is valid, otherwise ClassCastException is thrown. Behaves like java.lang.Double.compareTo().

Specified by:

compareTo in interface Comparable

Parameters:

other - Object to which to compare

Returns:

zero, less-than-zero, greater-than-zero.