net.sf.saxon.value
Class DoubleValue

java.lang.Object
  net.sf.saxon.value.Value
      net.sf.saxon.value.AtomicValue
          net.sf.saxon.value.NumericValue
              net.sf.saxon.value.DoubleValue

All Implemented Interfaces:

java.lang.Comparable, Expression, Item, java.io.Serializable, ValueRepresentation

public final class DoubleValue

extends NumericValue

A numeric (double precision floating point) value

See Also:

Serialized Form

Field Summary

static DoubleValue	NaN
static DoubleValue	ZERO

Fields inherited from class net.sf.saxon.value.Value

EMPTY_CLASS_ARRAY

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Fields inherited from interface net.sf.saxon.expr.Expression

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

DoubleValue(java.lang.CharSequence val)
Constructor supplying a string

DoubleValue(double value)
Constructor supplying a double

Method Summary

NumericValue	arithmetic(int operator, NumericValue other, XPathContext context) Evaluate a binary arithmetic operator.
NumericValue	ceiling() Implement the XPath ceiling() function
AtomicValue	convertPrimitive(BuiltInAtomicType requiredType, boolean validate, XPathContext context) Convert to target data type
java.lang.Object	convertToJava(java.lang.Class target, XPathContext context) Convert to Java object (for passing to external functions)
static java.lang.CharSequence	doubleToString(double value) Internal method used for conversion of a double to a string
static java.lang.CharSequence	doubleToStringOLD(double value, java.lang.String javaString) Internal method used for conversion of a double to a string
boolean	effectiveBooleanValue(XPathContext context) Get the effective boolean value
NumericValue	floor() Implement the XPath floor() function
double	getDoubleValue() Return this numeric value as a double
ItemType	getItemType(TypeHierarchy th) Determine the data type of the expression
java.lang.String	getStringValue() Convert the double to a string according to the XPath 2.0 rules
java.lang.CharSequence	getStringValueCS() Convert the double to a string according to the XPath 2.0 rules
int	hashCode() Get the hashCode.
boolean	isNaN() Test whether the value is the double/float value NaN
boolean	isWholeNumber() Determine whether the value is a whole number, that is, whether it compares equal to some integer
NumericValue	negate() Negate the value
static void	printInternalForm(double d) Diagnostic method
NumericValue	round() Implement the XPath round() function
NumericValue	roundToHalfEven(int scale) Implement the XPath round-to-half-even() function
boolean	schemaEquals(Value obj) Compare two values for equality.
double	signum() Determine whether the value is negative, zero, or positive

Methods inherited from class net.sf.saxon.value.NumericValue

compareTo, equals, isInteger, longValue, parseNumber, promote, toString

Methods inherited from class net.sf.saxon.value.AtomicValue

checkPermittedContents, convert, convert, display, evaluateAsString, evaluateItem, getCardinality, getComponent, getImplementationMethod, getLength, getPrimitiveValue, getTypedValue, hasBuiltInType, iterate, process

Methods inherited from class net.sf.saxon.value.Value

asItem, asIterator, asValue, collapseWhitespace, convert, convertJavaObjectToXPath, getDependencies, getIterator, getParentExpression, getSpecialProperties, itemAt, iterateSubExpressions, makeQNameValue, normalizeWhitespace, optimize, promote, reduce, simplify, stringToNumber, trimWhitespace, typeCheck

Methods inherited from class java.lang.Object

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

Field Detail

ZERO

public static final DoubleValue ZERO

NaN

public static final DoubleValue NaN

Constructor Detail

DoubleValue

public DoubleValue(java.lang.CharSequence val)
            throws ValidationException

Constructor supplying a string

Throws:

ValidationException - if the string does not have the correct lexical form for a double. Note that the error will contain no error code or context information.

DoubleValue

public DoubleValue(double value)

Constructor supplying a double

Parameters:

value - the value of the NumericValue

Method Detail

getDoubleValue

public double getDoubleValue()

Return this numeric value as a double

Overrides:

getDoubleValue in class NumericValue

Returns:

the value as a double

hashCode

public int hashCode()

Get the hashCode. This must conform to the rules for other NumericValue hashcodes

Specified by:

hashCode in class NumericValue

Returns:

the hash code of the numeric value

See Also:

NumericValue.hashCode()

isNaN

public boolean isNaN()

Test whether the value is the double/float value NaN

Overrides:

isNaN in class NumericValue

effectiveBooleanValue

public boolean effectiveBooleanValue(XPathContext context)

Get the effective boolean value

Specified by:

effectiveBooleanValue in interface Expression

Overrides:

effectiveBooleanValue in class AtomicValue

Parameters:

context -

Returns:

the effective boolean value (true unless the value is zero or NaN)

convertPrimitive

public AtomicValue convertPrimitive(BuiltInAtomicType requiredType,
                                    boolean validate,
                                    XPathContext context)

Convert to target data type

Specified by:

convertPrimitive in class AtomicValue

Parameters:

requiredType - an integer identifying the required atomic type

context -

validate - true if validation is required. If set to false, the caller guarantees that the value is valid for the target data type, and that further validation is therefore not required. Note that a validation failure may be reported even if validation was not requested.

Returns:

an AtomicValue, a value of the required type

getStringValue

public java.lang.String getStringValue()

Convert the double to a string according to the XPath 2.0 rules

Specified by:

getStringValue in interface Item

Specified by:

getStringValue in class AtomicValue

Returns:

the string value

getStringValueCS

public java.lang.CharSequence getStringValueCS()

Convert the double to a string according to the XPath 2.0 rules

Specified by:

getStringValueCS in interface Item

Overrides:

getStringValueCS in class AtomicValue

Returns:

the string value

doubleToString

public static java.lang.CharSequence doubleToString(double value)

Internal method used for conversion of a double to a string

Parameters:

value - the actual value

Returns:

the value converted to a string, according to the XPath casting rules.

doubleToStringOLD

public static java.lang.CharSequence doubleToStringOLD(double value,
                                                       java.lang.String javaString)

Internal method used for conversion of a double to a string

Parameters:

value - the actual value

javaString - the result of converting the double to a string using the Java conventions. This value is adjusted as necessary to cater for the differences between the Java and XPath rules.

Returns:

the value converted to a string, according to the XPath casting rules.

getItemType

public ItemType getItemType(TypeHierarchy th)

Determine the data type of the expression

Specified by:

getItemType in interface Expression

Overrides:

getItemType in class Value

Parameters:

th -

Returns:

Type.DOUBLE

negate

public NumericValue negate()

Negate the value

Specified by:

negate in class NumericValue

Returns:

a value, of the same type as the original, with its sign inverted

floor

public NumericValue floor()

Implement the XPath floor() function

Specified by:

floor in class NumericValue

Returns:

a value, of the same type as that supplied, rounded towards minus infinity

ceiling

public NumericValue ceiling()

Implement the XPath ceiling() function

Specified by:

ceiling in class NumericValue

Returns:

a value, of the same type as that supplied, rounded towards plus infinity

round

public NumericValue round()

Implement the XPath round() function

Specified by:

round in class NumericValue

Returns:

a value, of the same type as that supplied, rounded towards the nearest whole number (0.5 rounded up)

roundToHalfEven

public NumericValue roundToHalfEven(int scale)

Implement the XPath round-to-half-even() function

Specified by:

roundToHalfEven in class NumericValue

Parameters:

scale - the decimal position for rounding: e.g. 2 rounds to a multiple of 0.01, while -2 rounds to a multiple of 100

Returns:

a value, of the same type as the original, rounded towards the nearest multiple of 10**(-scale), with rounding towards the nearest even number if two values are equally near

signum

public double signum()

Determine whether the value is negative, zero, or positive

Specified by:

signum in class NumericValue

Returns:

-1 if negative, 0 if zero (including negative zero), +1 if positive, NaN if NaN

isWholeNumber

public boolean isWholeNumber()

Determine whether the value is a whole number, that is, whether it compares equal to some integer

Specified by:

isWholeNumber in class NumericValue

Returns:

true if the value is a whole number

arithmetic

public NumericValue arithmetic(int operator,
                               NumericValue other,
                               XPathContext context)
                        throws XPathException

Evaluate a binary arithmetic operator.

Specified by:

arithmetic in class NumericValue

Parameters:

operator - the binary arithmetic operation to be performed. Uses the constants defined in the Tokenizer class

other - the other operand

Returns:

the result of the arithmetic operation

Throws:

XPathException - if an arithmetic error occurs

See Also:

Tokenizer

schemaEquals

public boolean schemaEquals(Value obj)

Compare two values for equality. This supports identity constraints in XML Schema, which allow list-valued elements and attributes to participate in key and uniqueness constraints. This method returns false if any error occurs during the comparison, or if any of the items in either sequence is a node rather than an atomic value. The default implementation of schemaEquals() is the same as equals(), but subclasses can override this.

Overrides:

schemaEquals in class AtomicValue

convertToJava

public java.lang.Object convertToJava(java.lang.Class target,
                                      XPathContext context)
                               throws XPathException

Convert to Java object (for passing to external functions)

Overrides:

convertToJava in class Value

Throws:

XPathException

printInternalForm

public static void printInternalForm(double d)

Diagnostic method