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

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
           
 
Constructor Summary
DoubleValue(double value)
          Constructor supplying a double
 
Method Summary
 NumericValue arithmetic(int operator, NumericValue other)
          Evaluate a binary arithmetic operator.
 double asDouble()
          Get the numeric value as a double
 NumericValue ceiling()
          Implement the XPath ceiling() function
 int conversionPreference(java.lang.Class required, Configuration config)
          Get conversion preference for this value to a Java class.
 AtomicValue convert(int requiredType)
          Convert to target data type
 java.lang.Object convertToJava(java.lang.Class target, Configuration config)
          Convert to Java object (for passing to external functions)
 void display(int level, NamePool pool)
          Diagnostic print of expression structure
 boolean effectiveBooleanValue(XPathContext context)
          Get the effective boolean value of the value
 NumericValue floor()
          Implement the XPath floor() function
 ItemType getItemType()
          Determine the data type of the expression
 java.lang.String getStringValue()
          Get the value of the item as a string
 double getValue()
          Get the value
 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
 NumericValue round()
          Implement the XPath round() function
 NumericValue roundToHalfEven(int scale)
          Implement the XPath round-to-half-even() function
 
Methods inherited from class net.sf.saxon.value.NumericValue
asLong, compareTo, equals, isInteger, promote, toString
 
Methods inherited from class net.sf.saxon.value.AtomicValue
convert, evaluateAsString, evaluateItem, getCardinality, getComponent, getPrimitiveValue, getTypedValue, iterate
 
Methods inherited from class net.sf.saxon.value.Value
analyze, asItem, asValue, collapseWhitespace, getDependencies, getSpecialProperties, getSubExpressions, inverse, normalizeWhitespace, promote, simplify, stringToNumber, trimWhitespace
 
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(double value)
Constructor supplying a double

Parameters:
value - the value of the NumericValue
Method Detail

getValue

public double getValue()
Get the value


asDouble

public double asDouble()
Description copied from class: NumericValue
Get the numeric value as a double

Overrides:
asDouble in class NumericValue
Returns:
A double representing this numeric value; NaN if it cannot be converted

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)
Description copied from class: AtomicValue
Get the effective boolean value of the value

Specified by:
effectiveBooleanValue in interface Expression
Overrides:
effectiveBooleanValue in class AtomicValue
Parameters:
context - the evaluation context (not used in this implementation)
Returns:
true, unless the value is boolean false, numeric zero, or zero-length string

convert

public AtomicValue convert(int requiredType)
                    throws XPathException
Convert to target data type

Specified by:
convert in class AtomicValue
Parameters:
requiredType - an integer identifying the required atomic type
Returns:
an AtomicValue, a value of the required type
Throws:
XPathException - if the conversion is not possible

getStringValue

public java.lang.String getStringValue()
Description copied from interface: Item
Get the value of the item as a string

Specified by:
getStringValue in interface Item
Specified by:
getStringValue in class Value
Returns:
the string value of the item

getItemType

public ItemType getItemType()
Determine the data type of the expression

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

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)
                        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

conversionPreference

public int conversionPreference(java.lang.Class required,
                                Configuration config)
Get conversion preference for this value to a Java class. A low result indicates higher preference.

Overrides:
conversionPreference in class AtomicValue

convertToJava

public java.lang.Object convertToJava(java.lang.Class target,
                                      Configuration config)
                               throws XPathException
Convert to Java object (for passing to external functions)

Overrides:
convertToJava in class AtomicValue
Parameters:
target - The class required by the external function
config - The configuration (needed for access to schema information)
Returns:
an object of the target class
XPathException

display

public void display(int level,
                    NamePool pool)
Diagnostic print of expression structure

Parameters:
level - indentation level for this expression