## net.sf.saxon.style
Class StylesheetFunctionLibrary

    java.lang.Object
      net.sf.saxon.style.StylesheetFunctionLibrary

All Implemented Interfaces:
  Serializable, FunctionLibrary

    public class StylesheetFunctionLibrary

extends Object
implements FunctionLibrary

A StylesheetFunctionLibrary contains functions defined by the user in a stylesheet. This library is used at compile time only, as it contains references to the actual XSLFunction objects. Binding to a function in this library registers the function call on a fix-up list to be notified when the actual compiled function becomes available.

See Also:
  Serialized Form

Constructor Summary
`StylesheetFunctionLibrary(PrincipalStylesheetModule sheet, boolean overriding)` Create a FunctionLibrary that provides access to stylesheet functions

Method Summary
`Expression` `bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env, Container container)` 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.
`SequenceType[]` `getFunctionSignature(StructuredQName functionName, int arity)` Test whether a function with a given name and arity is available; if so, return its signature.
`boolean` `isOverriding()` Ask whether the functions in this library are "overriding" functions, that is, defined with xsl:function override="yes".

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### StylesheetFunctionLibrary

    public StylesheetFunctionLibrary(PrincipalStylesheetModule sheet,
                                     boolean overriding)

  Create a FunctionLibrary that provides access to stylesheet functions

  Parameters:
    `sheet` - The XSLStylesheet element of the principal stylesheet module
    `overriding` - set to true if this library is to contain functions specifying override="yes", or to false if it is to contain functions specifying override="no". (XSLT uses two instances of this class, one for overriding functions and one for non-overriding functions.)

Method Detail

### isOverriding

    public boolean isOverriding()

  Ask whether the functions in this library are "overriding" functions, that is, defined with xsl:function override="yes".

  Returns:
    true if these are overriding functions, false otherwise

### getFunctionSignature

    public SequenceType[] getFunctionSignature(StructuredQName functionName,
                                               int arity)

  Test whether a function with a given name and arity is available; if so, return its signature. This supports the function-available() function in XSLT; it is also used to support higher-order functions introduced in XQuery 1.1.

  This method may be called either at compile time or at run time. If the function library is to be used only in an XQuery or free-standing XPath environment, this method may throw an UnsupportedOperationException.

  Specified by:
    `getFunctionSignature` in interface `FunctionLibrary`
  Parameters:
    `functionName` - the qualified name of the function being called
    `arity` - The number of arguments. This is set to -1 in the case of the single-argument function-available() function; in this case the method should return true if there is some function of this name available for calling.
  Returns:
    if a function of this name and arity is available for calling, then the type signature of the function, as an array of sequence types in which the zeroth entry represents the return type; or a zero-length array if the function exists but the signature is not known; or null if the function does not exist

### bind

    public Expression bind(StructuredQName functionName,
                           Expression[] staticArgs,
                           StaticContext env,
                           Container container)
                    throws XPathException

  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:
    `functionName` -
    `staticArgs` - The expressions supplied statically in 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.
    `env` -
    `container` -
  Returns:
    An object representing the extension function to be called, if one is found; null if no extension function was found matching the required name and arity.
  Throws:
    `XPathException` - if a function is found with the required name and arity, but the implementation of the function cannot be loaded or used; or if an error occurs while searching for the function; or if this function library "owns" the namespace containing the function call, but no function was found.

### 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.

Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.