net.sf.saxon.functions.registry

Class BuiltInFunctionSet

java.lang.Object

net.sf.saxon.functions.registry.BuiltInFunctionSet

All Implemented Interfaces:

FunctionLibrary

Direct Known Subclasses:

ArrayFunctionSet, EXPathFileFunctionSet, ExsltCommonFunctionSet, IXSLFunctionSet, MapFunctionSet, MathFunctionSet, SQLFunctionSet, UseWhen30FunctionSet, VendorFunctionSetEE, VendorFunctionSetHE, VendorFunctionSetPE, XPath20FunctionSet, XPath30FunctionSet, XPath30HOFunctionSet, XPath31FunctionSet, XPath31HOFunctionSet, XQUpdate10FunctionSet, XSLT30FunctionSet, XSLT30HOFunctionSet

public abstract class BuiltInFunctionSet
extends java.lang.Object
implements FunctionLibrary

This class is used to contain information about a set of built-in functions.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BuiltInFunctionSet.Entry An entry in the table describing the properties of a function

Field Summary

Fields

Modifier and Type	Field and Description
static int	ABS
static int	AS_ARG0 Function properties
static int	AS_PRIM_ARG0
static int	BASE
static int	CARD0
static int	CDOC
static int	CITEM
static int	CORE Categories of functions, bit significant
static int	DCOLL
static int	DEPENDS_ON_STATIC_CONTEXT
static int	DLANG
static Sequence<?>	EMPTY
static int	FILTER
static int	FOCUS
static int	HOF
static int	INS Classification of function arguments for serialization purposes; note that values must not conflict with bit settings used for cardinalities
static int	INTERNAL
static int	LAST
static int	LATE
static int	NAV
static int	NEW
static int	NS
static int	ONE Local names used for cardinality values
static int	OPT
static int	PLUS
static int	POSN
static int	SIDE
static int	STAR
static int	TRA
static int	UO
static int	USE_WHEN
static int	XPATH30
static int	XPATH31
static int	XQUPDATE
static int	XSLT
static int	XSLT30

Constructor Summary

Constructors

Constructor and Description
BuiltInFunctionSet()

Method Summary

Modifier and Type	Method and Description
Expression	bind(SymbolicName.F symbolicName, Expression[] staticArgs, StaticContext env, java.util.List<java.lang.String> reasons) Bind a function, given the URI and local parts of the function name, and the list of expressions supplied as arguments.
FunctionLibrary	copy() This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows new functions to be added, then additions to this copy will not affect the original, or vice versa.
java.lang.String	getConventionalPrefix() Return a conventional prefix for use with this namespace, typically the prefix used in the documentation of these functions.
BuiltInFunctionSet.Entry	getFunctionDetails(java.lang.String name, int arity) Locate the entry for a function with a given name and arity, if it exists
Function	getFunctionItem(SymbolicName.F symbolicName, StaticContext staticContext) Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.
java.lang.String	getNamespace() Return the namespace URI for the functions local to this function set.
void	importFunctionSet(BuiltInFunctionSet importee) Import another function set (which must be in the same namespace)
boolean	isAvailable(SymbolicName.F symbolicName) Test whether a function with a given name and arity is available
SystemFunction	makeFunction(java.lang.String name, int arity)
protected BuiltInFunctionSet.Entry	register(java.lang.String name, int arity, java.lang.Class<? extends SystemFunction> implementationClass, ItemType itemType, int cardinality, int applicability, int properties) Register a system function in the table of function details.
protected void	registerReducedArityVariants(java.lang.String key, int min, int max) Register reduced-arity versions of a function, with arities in a specified range, using common argument and return types

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.functions.FunctionLibrary

setConfiguration

Field Detail

EMPTY

public static Sequence<?> EMPTY

CORE

public static final int CORE

Categories of functions, bit significant

See Also:

Constant Field Values

XSLT

public static final int XSLT

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USE_WHEN

public static final int USE_WHEN

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XQUPDATE

public static final int XQUPDATE

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XPATH30

public static final int XPATH30

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INTERNAL

public static final int INTERNAL

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XSLT30

public static final int XSLT30

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XPATH31

public static final int XPATH31

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HOF

public static final int HOF

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ONE

public static final int ONE

Local names used for cardinality values

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OPT

public static final int OPT

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STAR

public static final int STAR

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PLUS

public static final int PLUS

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AS_ARG0

public static final int AS_ARG0

Function properties

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AS_PRIM_ARG0

public static final int AS_PRIM_ARG0

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CITEM

public static final int CITEM

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BASE

public static final int BASE

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NS

public static final int NS

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DCOLL

public static final int DCOLL

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DLANG

public static final int DLANG

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FILTER

public static final int FILTER

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LATE

public static final int LATE

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UO

public static final int UO

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POSN

public static final int POSN

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LAST

public static final int LAST

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SIDE

public static final int SIDE

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CDOC

public static final int CDOC

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CARD0

public static final int CARD0

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NEW

public static final int NEW

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DEPENDS_ON_STATIC_CONTEXT

public static final int DEPENDS_ON_STATIC_CONTEXT

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FOCUS

public static final int FOCUS

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INS

public static final int INS

Classification of function arguments for serialization purposes; note that values must not conflict with bit settings used for cardinalities

See Also:

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ABS

public static final int ABS

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TRA

public static final int TRA

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NAV

public static final int NAV

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Constructor Detail

BuiltInFunctionSet

public BuiltInFunctionSet()

Method Detail

importFunctionSet

public final void importFunctionSet(BuiltInFunctionSet importee)

Import another function set (which must be in the same namespace)

Parameters:

importee - the function set to be imported. (No cycles allowed!)

getFunctionDetails

public BuiltInFunctionSet.Entry getFunctionDetails(java.lang.String name,
                                                   int arity)

Locate the entry for a function with a given name and arity, if it exists

Parameters:

name - the local part of the function name

arity - the arity of the function. -1 considers all possibly arities and returns an arbitrary function if one exists with the right name.

Returns:

the entry for the required function, or null if not found

bind

public Expression bind(SymbolicName.F symbolicName,
                       Expression[] staticArgs,
                       StaticContext env,
                       java.util.List<java.lang.String> reasons)

Bind a function, given the URI and local parts of the function name, and the list of expressions supplied as arguments. This method is called at compile time.

Specified by:

bind in interface FunctionLibrary

Parameters:

symbolicName - the symbolic name of the function being called

staticArgs - May be null; if present, the length of the array must match the value of arity. Contains the expressions supplied statically in arguments to the function call. The intention is that the static type of the arguments (obtainable via getItemType() and getCardinality()) may be used as part of the binding algorithm. In some cases it may be possible for the function to be pre-evaluated at compile time, for example if these expressions are all constant values.

The conventions of the XPath language demand that the results of a function depend only on the values of the expressions supplied as arguments, and not on the form of those expressions. For example, the result of f(4) is expected to be the same as f(2+2). The actual expression is supplied here to enable the binding mechanism to select the most efficient possible implementation (including compile-time pre-evaluation where appropriate).

env - The static context of the function call

reasons - If no matching function is found by the function library, it may add a diagnostic explanation to this list explaining why none of the available functions could be used.

Returns:

An expression equivalent to a call on the specified function, if one is found; null if no function was found matching the required name and arity.

makeFunction

public SystemFunction makeFunction(java.lang.String name,
                                   int arity)
                            throws XPathException

Throws:

XPathException

isAvailable

public boolean isAvailable(SymbolicName.F symbolicName)

Test whether a function with a given name and arity is available

This supports the function-available() function in XSLT.

Specified by:

isAvailable in interface FunctionLibrary

Parameters:

symbolicName - the qualified name of the function being called, together with its arity. For legacy reasons, the arity may be set to -1 to mean any arity will do

Returns:

true if a function of this name and arity is available for calling

copy

public FunctionLibrary copy()

This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows new functions to be added, then additions to this copy will not affect the original, or vice versa.

Specified by:

copy in interface FunctionLibrary

Returns:

a copy of this function library. This must be an instance of the original class.

getFunctionItem

public Function getFunctionItem(SymbolicName.F symbolicName,
                                StaticContext staticContext)
                         throws XPathException

Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.

This supports the function-lookup() function in XPath 3.0.

Specified by:

getFunctionItem in interface FunctionLibrary

Parameters:

symbolicName - the qualified name of the function being called

staticContext - the static context to be used by the function, in the event that it is a system function with dependencies on the static context

Returns:

if a function of this name and arity is available for calling, then a corresponding function item; or null if the function does not exist

Throws:

XPathException - in the event of certain errors, for example attempting to get a function that is private

register

protected BuiltInFunctionSet.Entry register(java.lang.String name,
                                            int arity,
                                            java.lang.Class<? extends SystemFunction> implementationClass,
                                            ItemType itemType,
                                            int cardinality,
                                            int applicability,
                                            int properties)

Register a system function in the table of function details.

Parameters:

name - the function name

implementationClass - the class used to implement the function

itemType - the item type of the result of the function

cardinality - the cardinality of the result of the function

applicability - the host languages (and versions thereof) in which this function is available

properties - bitwise properties of the function

Returns:

the entry describing the function. The entry is incomplete, it does not yet contain information about the function arguments.

registerReducedArityVariants

protected void registerReducedArityVariants(java.lang.String key,
                                            int min,
                                            int max)

Register reduced-arity versions of a function, with arities in a specified range, using common argument and return types

getNamespace

public java.lang.String getNamespace()

Return the namespace URI for the functions local to this function set.

Returns:

the namespace URI of the functions local to this function set. Note that functions imported from another function set may have a different namespace URI.

getConventionalPrefix

public java.lang.String getConventionalPrefix()

Return a conventional prefix for use with this namespace, typically the prefix used in the documentation of these functions.