net.sf.saxon.functions
Class StandardFunction

java.lang.Object
  net.sf.saxon.functions.StandardFunction

public abstract class StandardFunction
extends Object

This class contains static data tables defining the properties of standard functions. "Standard functions" here means the XPath 2.0 functions, the XSLT 2.0 functions, and a few selected extension functions which need special recognition.

Nested Class Summary

static class

StandardFunction.Entry An entry in the table describing the properties of a function

Field Summary

static int	CORE Categories of functions, bit significant
static Value	EMPTY
static int	INTERNAL
protected static ItemType	SAME_AS_FIRST_ARGUMENT
static int	USE_WHEN
static int	XPATH30
static int	XQUPDATE
static int	XSLT
static int	XSLT30

Method Summary

static void	arg(StandardFunction.Entry e, int a, ItemType type, int cardinality, Value resultIfEmpty) Add information to a function entry about the argument types of the function
static StandardFunction.Entry	getFunction(String name, int arity) Get the table entry for the function with a given name
static StandardFunction.Entry	makeEntry(String name, Class implementationClass, int opcode, int minArguments, int maxArguments, ItemType itemType, int cardinality, int applicability) Make a table entry describing the signature of a function, with a reference to the implementation class.
static StandardFunction.Entry	register(String name, Class implementationClass, int opcode, int minArguments, int maxArguments, ItemType itemType, int cardinality, int applicability) Register a system function in the table of function details.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static Value EMPTY

CORE

public static final int CORE

Categories of functions, bit significant

See Also:

Constant Field Values

XSLT

public static final int XSLT

See Also:

Constant Field Values

USE_WHEN

public static final int USE_WHEN

See Also:

Constant Field Values

XQUPDATE

public static final int XQUPDATE

See Also:

Constant Field Values

XPATH30

public static final int XPATH30

See Also:

Constant Field Values

INTERNAL

public static final int INTERNAL

See Also:

Constant Field Values

XSLT30

public static final int XSLT30

See Also:

Constant Field Values

SAME_AS_FIRST_ARGUMENT

protected static ItemType SAME_AS_FIRST_ARGUMENT

Method Detail

register

public static StandardFunction.Entry register(String name,
                                              Class implementationClass,
                                              int opcode,
                                              int minArguments,
                                              int maxArguments,
                                              ItemType itemType,
                                              int cardinality,
                                              int applicability)

Register a system function in the table of function details.

Parameters:

name - the function name

implementationClass - the class used to implement the function

opcode - identifies the function when a single class implements several functions

minArguments - the minimum number of arguments required

maxArguments - the maximum number of arguments allowed

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

Returns:

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

makeEntry

public static StandardFunction.Entry makeEntry(String name,
                                               Class implementationClass,
                                               int opcode,
                                               int minArguments,
                                               int maxArguments,
                                               ItemType itemType,
                                               int cardinality,
                                               int applicability)

Make a table entry describing the signature of a function, with a reference to the implementation class.

Parameters:

name - the function name

implementationClass - the class used to implement the function

opcode - identifies the function when a single class implements several functions

minArguments - the minimum number of arguments required

maxArguments - the maximum number of arguments allowed

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 of) in which this function is available

Returns:

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

arg

public static void arg(StandardFunction.Entry e,
                       int a,
                       ItemType type,
                       int cardinality,
                       Value resultIfEmpty)

Add information to a function entry about the argument types of the function

Parameters:

e - the entry for the function

a - the position of the argument, counting from zero

type - the item type of the argument

cardinality - the cardinality of the argument

resultIfEmpty - the value returned by the function if an empty sequence appears as the value of this argument, in the case when this result is unaffected by any other arguments. Supply null if this does not apply.

getFunction

public static StandardFunction.Entry getFunction(String name,
                                                 int arity)

Get the table entry for the function with a given name

Parameters:

name - the name of the function. This may be an unprefixed local-name for functions in the system namespace, or may use the conventional prefix "saxon:" in the case of Saxon extension functions that are specially recognized

arity - the number of arguments of the function

Returns:

if the function name is known, an Entry containing information about the function. Otherwise, null