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

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

Methods inherited from class java.lang.Object

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

Method Detail

makeEntry

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

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

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, when this result is unaffected by any other arguments

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

Returns:

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