net.sf.saxon.functions

Class NumberFn

Implemented Interfaces:
EvaluableItem, InstructionInfoProvider, ItemMappingFunction, SequenceIterable, Serializable, SourceLocator

public class NumberFn
extends SystemFunction
implements ItemMappingFunction

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.

Field Summary

Fields inherited from class net.sf.saxon.functions.SystemFunction

operation

Fields inherited from class net.sf.saxon.expr.FunctionCall

argument

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD, locationId, staticProperties

Method Summary

PathMap.PathMapNodeSet
addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes)
Add a representation of a doc() call or similar function to a PathMap.
static DoubleValue
convert(AtomicValue value)
Static method to perform the same conversion as the number() function.
Item
evaluateItem(XPathContext context)
Evaluate in a general context
Item
map(Item item)
Mapping function for use when converting a sequence of atomic values to doubles using the rules of the number() function
Expression
simplify(ExpressionVisitor visitor)
Simplify and validate.

Methods inherited from class net.sf.saxon.functions.SystemFunction

addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

Methods inherited from class net.sf.saxon.expr.FunctionCall

addExternalFunctionCallToPathMap, checkArgumentCount, checkArguments, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, optimize, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

Methods inherited from class net.sf.saxon.expr.Expression

addToPathMap, adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, optimize, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Method Details

addDocToPathMap

public PathMap.PathMapNodeSet addDocToPathMap(PathMap pathMap,
                                              PathMap.PathMapNodeSet pathMapNodes)
Add a representation of a doc() call or similar function to a PathMap. This is a convenience method called by the addToPathMap() methods for doc(), document(), collection() and similar functions. These all create a new root expression in the path map.
Overrides:
addDocToPathMap in interface SystemFunction
Parameters:
pathMap - the PathMap to which the expression should be added
pathMapNodes - the node in the PathMap representing the focus at the point where this expression is called. Set to null if this expression appears at the top level.
Returns:
the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter 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.
Parameters:
value - the value to be converted
Returns:
the result of the conversion

evaluateItem

public Item evaluateItem(XPathContext context)
            throws XPathException
Evaluate in a general context
Specified by:
evaluateItem in interface EvaluableItem
Overrides:
evaluateItem in interface Expression

map

public Item map(Item item)
            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 ItemMappingFunction

simplify

public Expression simplify(ExpressionVisitor visitor)
            throws XPathException
Simplify and validate. This is a pure function so it can be simplified in advance if the arguments are known
Overrides:
simplify in interface FunctionCall
Parameters:
visitor - an expression visitor