net.sf.saxon.functions
Class NumberFn
java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.NumberFn
- All Implemented Interfaces:
- Container, Expression, InstructionInfoProvider, MappingFunction, Serializable, SourceLocator
- public class NumberFn
- extends SystemFunction
- implements MappingFunction
Implements the XPath number() function. This can also be used as a mapping function
in a MappingIterator to map a sequence of values to numbers.
- See Also:
- Serialized Form
Methods inherited from class net.sf.saxon.functions.SystemFunction |
addContextDocumentArgument, checkArguments, computeCardinality, computeSpecialProperties, display, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, main, makeSystemFunction, setDetails, useContextItemAsDefault |
Methods inherited from class net.sf.saxon.expr.FunctionCall |
checkArgumentCount, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, preEvaluate, promote, setArguments, setFunctionNameCode, simplifyArguments, typeCheck |
Methods inherited from class net.sf.saxon.expr.ComputedExpression |
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
NumberFn
public NumberFn()
simplify
public Expression simplify(StaticContext env)
throws XPathException
- Simplify and validate.
This is a pure function so it can be simplified in advance if the arguments are known
- Specified by:
simplify
in interface Expression
- Overrides:
simplify
in class FunctionCall
- Throws:
XPathException
evaluateItem
public Item evaluateItem(XPathContext context)
throws XPathException
- Evaluate in a general context
- Specified by:
evaluateItem
in interface Expression
- Overrides:
evaluateItem
in class ComputedExpression
- Parameters:
context
- The context in which the expression is to be evaluated
- Returns:
- the node or atomic value that results from evaluating the
expression; or null to indicate that the result is an empty
sequence
- Throws:
XPathException
- if any dynamic error occurs evaluating the
expression
convert
public static DoubleValue convert(AtomicValue value)
- Static method to perform the same conversion as the number() function. This is different from the
convert(Type.DOUBLE) in that it produces NaN rather than an error for non-numeric operands.
map
public Object map(Item item,
XPathContext context)
throws XPathException
- Mapping function for use when converting a sequence of atomic values to doubles
using the rules of the number() function
- Specified by:
map
in interface MappingFunction
- Parameters:
item
- The item to be mapped.
If context is supplied, this must be the same as context.currentItem().context
- The processing context. Some mapping functions use this because they require
context information. Some mapping functions modify the context by maintaining the context item
and position. In other cases, the context may be null.
- Returns:
- either (a) a SequenceIterator over the sequence of items that the supplied input
item maps to, or (b) an Item if it maps to a single item, or (c) null if it maps to an empty
sequence.
- Throws:
XPathException