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
           
 
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 convert(int requiredType, XPathContext context)
          Convert to target data type
 java.lang.Object convertToJava(java.lang.Class target, Configuration config, XPathContext context)
          Convert to Java object (for passing to external functions)
 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()
          Determine the data type of the expression
 java.lang.String getStringValue()
          Convert the value to a string, using the serialization 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
 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
compareTo, equals, isInteger, longValue, parseNumber, promote, toString
 
Methods inherited from class net.sf.saxon.value.AtomicValue
convert, display, evaluateAsString, evaluateItem, getCardinality, getComponent, getImplementationMethod, getPrimitiveValue, getTypedValue, iterate, process
 
Methods inherited from class net.sf.saxon.value.Value
analyze, asItem, asValue, collapseWhitespace, convertJavaObjectToXPath, getDependencies, getParentExpression, getSpecialProperties, inverse, iterateSubExpressions, 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(java.lang.CharSequence val)
            throws DynamicError
Constructor supplying a string

Throws:
DynamicError - 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)

convert

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

Specified by:
convert in class AtomicValue
Parameters:
requiredType - an integer identifying the required atomic type
context - the evaluation context. Used primarily for error reporting, since nearly all type conversions are context-independent. The value may be null if the context is not known.
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 class: AtomicValue
Convert the value to a string, using the serialization rules. For atomic values this is the same as a cast; for sequence values it gives a space-separated list. This method is refined for AtomicValues so that it never throws an Exception.

Specified by:
getStringValue in interface Item
Specified by:
getStringValue in class AtomicValue
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,
                               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

convertToJava

public java.lang.Object convertToJava(java.lang.Class target,
                                      Configuration config,
                                      XPathContext context)
                               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