Package net.sf.saxon.functions
Class NumberFn
- java.lang.Object
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- net.sf.saxon.expr.ComputedExpression
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- net.sf.saxon.expr.FunctionCall
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- net.sf.saxon.functions.SystemFunction
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- net.sf.saxon.functions.NumberFn
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,Container
,Expression
,ItemMappingFunction
,InstructionInfoProvider
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.- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class net.sf.saxon.functions.SystemFunction
operation
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Fields inherited from class net.sf.saxon.expr.FunctionCall
argument
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Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
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Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors Constructor Description NumberFn()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static DoubleValue
convert(AtomicValue value)
Static method to perform the same conversion as the number() function.Item
evaluateItem(XPathContext context)
Evaluate in a general contextItem
map(Item item)
Mapping function for use when converting a sequence of atomic values to doubles using the rules of the number() functionExpression
simplify(StaticContext env)
Simplify and validate.-
Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, checkArguments, computeCardinality, computeSpecialProperties, display, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, main, makeSystemFunction, setDetails, useContextItemAsDefault
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Methods inherited from class net.sf.saxon.expr.FunctionCall
checkArgumentCount, getArguments, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplifyArguments, typeCheck
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Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, 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, setParentExpression, suppressValidation, typeError
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Method Detail
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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 interfaceExpression
- Overrides:
simplify
in classFunctionCall
- Parameters:
env
- the static context- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
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evaluateItem
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate in a general context- Specified by:
evaluateItem
in interfaceExpression
- Overrides:
evaluateItem
in classComputedExpression
- 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
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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.
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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 interfaceItemMappingFunction
- Parameters:
item
- The input item to be mapped.- Returns:
- either the output item, or null.
- Throws:
XPathException
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