NumberFn

java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.expr.FunctionCall
  - - net.sf.saxon.functions.SystemFunction
    - - net.sf.saxon.functions.NumberFn

All Implemented Interfaces:

java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, ItemMappingFunction, SequenceIterable, InstructionInfo, org.xml.sax.Locator
```
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

Field Summary
- Fields inherited from class net.sf.saxon.expr.Expression
  EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties
- Fields inherited from class net.sf.saxon.expr.FunctionCall
  argument
- Fields inherited from class net.sf.saxon.functions.SystemFunction
  operation

Constructor Summary

Constructors
Constructor Description

NumberFn()

Constructors
Constructor	Description
`NumberFn()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`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.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterate, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError

Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplifyArguments, toString, typeCheck

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

- 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 FunctionCall
    
    Parameters:
    
    visitor - an expression visitor
    
    Returns:
    
    the simplified expression
    
    Throws:
    
    XPathException - if an error is discovered during expression rewriting
  - 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 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
  - evaluateItem
```
public Item evaluateItem(XPathContext context)
                  throws XPathException
```
    Evaluate in a general context
    
    Specified by:
    
    evaluateItem in interface EvaluableItem
    
    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)
```
    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
  - 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
    
    Parameters:
    
    item - The input item to be mapped.
    
    Returns:
    
    either the output item, or null.
    
    Throws:
    
    XPathException

Class NumberFn

Field Summary

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

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

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

NumberFn

Method Detail

simplify

addDocToPathMap

evaluateItem

convert

map