net.sf.saxon.functions

Class NumberFn

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.FunctionCall

net.sf.saxon.functions.SystemFunctionCall

net.sf.saxon.functions.NumberFn

All Implemented Interfaces:

SourceLocator, Callable, IdentityComparable, InstructionInfo

public class NumberFn
extends SystemFunctionCall
implements Callable

Implements the XPath number() function.

Field Summary

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

operation

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

argument

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

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD

Constructor Summary

Constructors

Constructor and Description
NumberFn()

Method Summary

Methods

Modifier and Type	Method and Description
PathMap.PathMapNodeSet	addDocToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodes) Add a representation of a doc() call or similar function to a PathMap.
DoubleValue	call(XPathContext context, Sequence[] arguments) Evaluate the expression
static DoubleValue	convert(AtomicValue value, Configuration config) Static method to perform the same conversion as the number() function.
DoubleValue	evaluateItem(XPathContext context) Evaluate in a general context
ExpressionCompiler	getExpressionCompiler() Return the compiler of the NumberFn expression
Expression	simplify(ExpressionVisitor visitor) Simplify and validate.
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Type-check the expression.

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

addContextDocumentArgument, bindStaticContext, checkArguments, computeCardinality, computeSpecialProperties, copy, equalOrNull, equals, getContextNode, getConvertingCallable, getDefaultArgumentNode, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getImplementationMethod, getItemType, getOperation, getRequiredType, makeSystemFunction, operands, optimize, setDetails, toShortString, useContextItemAsDefault

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

addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, preEvaluate, promote, replaceOperand, setArguments, setFunctionName, simplifyArguments, toString

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

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getConstructType, getContainer, getDependencies, getEvaluationMethod, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLocationId, getObjectName, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getStreamingAdjunct, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError, unordered

Methods inherited from class java.lang.Object

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

Constructor Detail

NumberFn

public NumberFn()

Method Detail

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 class Expression

Parameters:

visitor - an expression visitor

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                   ContextItemStaticInfo contextInfo)
                     throws XPathException

Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.

Overrides:

typeCheck in class FunctionCall

Parameters:

visitor - an expression visitor

contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

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 class SystemFunctionCall

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

evaluateItem

public DoubleValue evaluateItem(XPathContext context)
                         throws XPathException

Evaluate in a general context

Overrides:

evaluateItem in class Expression

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,
                  Configuration config)

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

config - the Saxon configuration

Returns:

the result of the conversion

call

public DoubleValue call(XPathContext context,
               Sequence[] arguments)
                 throws XPathException

Evaluate the expression

Specified by:

call in interface Callable

Parameters:

context - the dynamic evaluation context

arguments - the values of the arguments, supplied as Sequences

Returns:

the result of the evaluation, in the form of a Sequence

Throws:

XPathException - if a dynamic error occurs during the evaluation of the expression

getExpressionCompiler

public ExpressionCompiler getExpressionCompiler()

Return the compiler of the NumberFn expression

Overrides:

getExpressionCompiler in class Expression

Returns:

the relevant ExpressionCompiler