Class SystemFunction

java.lang.Object

net.sf.saxon.expr.ComputedExpression

net.sf.saxon.expr.FunctionCall

net.sf.saxon.functions.SystemFunction

All Implemented Interfaces:

Serializable, SourceLocator, Container, Expression, InstructionInfoProvider

Direct Known Subclasses:

Adjust, Aggregate, Available, BaseURI, BooleanFn, CodepointEqual, CollatingFunction, Collection, CompileTimeFunction, Component, Concat, Current, CurrentDateTime, CurrentGroup, DateTimeConstructor, Doc, Document, Error, EscapeURI, Evaluate, Existence, ForceCase, FormatDate, FormatNumber2, Id, Idref, InScopePrefixes, Insert, KeyFn, Lang, Last, Matches, NamePart, NamespaceForPrefix, Nilled, NormalizeSpace, NormalizeUnicode, NumberFn, Parse, Position, QNameFn, RegexGroup, Remove, Replace, ResolveQName, ResolveURI, Root, Rounding, Serialize, StringFn, StringJoin, StringLength, Subsequence, Substring, SystemProperty, Tokenize, Trace, Translate, TreatFn, Unicode, UnparsedEntity, UnparsedText

public abstract class SystemFunction
extends FunctionCall

Abstract superclass for system-defined and user-defined functions

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected int	operation

Fields inherited from class FunctionCall

argument

Fields inherited from class ComputedExpression

locationId, staticProperties

Fields inherited from interface Expression

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

Constructors

Constructor	Description
SystemFunction()

Method Summary

Modifier and Type	Method	Description
protected final void	addContextDocumentArgument(int pos, String augmentedName)	Add an implicit argument referring to the context document.
void	checkArguments(StaticContext env)	Method called during static type checking
int	computeCardinality()	Determine the cardinality of the function.
int	computeSpecialProperties()	Determine the special properties of this expression.
void	display(int level, PrintStream out, Configuration config)	Diagnostic print of expression structure
StandardFunction.Entry	getDetails()	Get the details
String	getErrorCodeForTypeErrors()	Return the error code to be used for type errors.
ItemType	getItemType(TypeHierarchy th)	Determine the item type of the value returned by the function
protected SequenceType	getRequiredType(int arg)	Get the required type of the nth argument
static void	main(String[] args)	The main() method of this class is not intended to be called, it merely tells the code inspection tools in IDEA that the constructors of each function class are actual entry points
static FunctionCall	makeSystemFunction(String name, int arity, NamePool pool)	Make a system function (one in the standard function namespace).
void	setDetails(StandardFunction.Entry entry)	Set the details of this type of function
protected final void	useContextItemAsDefault()	Set "." as the default value for the first and only argument.

Methods inherited from class FunctionCall

checkArgumentCount, getArguments, getDisplayName, getFunctionNameCode, getNumberOfArguments, iterateSubExpressions, optimize, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionNameCode, simplify, simplifyArguments, typeCheck

Methods inherited from class ComputedExpression

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, 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

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

operation

protected int operation

Constructor Details

SystemFunction

public SystemFunction()

Method Details

makeSystemFunction

public static FunctionCall makeSystemFunction(String name,
 int arity,
 NamePool pool)

Make a system function (one in the standard function namespace).

Parameters:

name - The local name of the function. It may also be a lexical QName for a recognized built-in function, e.g. saxon:evaluate, in which case the prefix is hard-coded.

Returns:

a FunctionCall that implements this function, if it exists, or null if the function is unknown.

setDetails

public void setDetails(StandardFunction.Entry entry)

Set the details of this type of function

getDetails

public StandardFunction.Entry getDetails()

Get the details

checkArguments

public void checkArguments(StaticContext env)
                    throws XPathException

Method called during static type checking

Specified by:

checkArguments in class FunctionCall

Throws:

XPathException

getErrorCodeForTypeErrors

public String getErrorCodeForTypeErrors()

Return the error code to be used for type errors. This is overridden for functions such as exactly-one(), one-or-more(), ...

getRequiredType

protected SequenceType getRequiredType(int arg)

Get the required type of the nth argument

getItemType

public ItemType getItemType(TypeHierarchy th)

Determine the item type of the value returned by the function

Parameters:

th -

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

computeCardinality

public int computeCardinality()

Determine the cardinality of the function.

Specified by:

computeCardinality in class ComputedExpression

computeSpecialProperties

public int computeSpecialProperties()

Determine the special properties of this expression. The general rule is that a system function call is non-creative if its return type is atomic, or if all its arguments are non-creative. This is overridden for the generate-id() function, which is considered creative if its operand is creative (because the result depends on the identity of the operand)

Overrides:

computeSpecialProperties in class ComputedExpression

useContextItemAsDefault

protected final void useContextItemAsDefault()

Set "." as the default value for the first and only argument. Called from subclasses.

addContextDocumentArgument

protected final void addContextDocumentArgument(int pos,
 String augmentedName)
                                         throws StaticError

Add an implicit argument referring to the context document. Called by functions such as id() and key() that take the context document as an implicit argument

Throws:

StaticError

display

public void display(int level,
 PrintStream out,
 Configuration config)

Diagnostic print of expression structure

Specified by:

display in interface Expression

Overrides:

display in class FunctionCall

Parameters:

level - indentation level for this expression

out - Output destination

config -

main

public static void main(String[] args)
                 throws Exception

The main() method of this class is not intended to be called, it merely tells the code inspection tools in IDEA that the constructors of each function class are actual entry points

Throws:

Exception