## 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(XSLStylesheet sheet, boolean overriding)` Create a FunctionLibrary that provides access to stylesheet functions

Method Summary
`Expression` `bind(int nameCode, String uri, String local, Expression[] staticArgs)` 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.
`boolean` `isAvailable(int fingerprint, String uri, String local, int arity)` Test whether a Saxon function with a given name and arity is available.

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

Constructor Detail

### StylesheetFunctionLibrary

    public StylesheetFunctionLibrary(XSLStylesheet 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

### isAvailable

    public boolean isAvailable(int fingerprint,
                               String uri,
                               String local,
                               int arity)

  Test whether a Saxon function with a given name and arity is available. This supports the function-available() function in XSLT.

  Specified by:
    `isAvailable` in interface `FunctionLibrary`
  Parameters:
    `uri` - The URI of the function name
    `local` - The local part of the function name
    `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 matching extension function, regardless of its arity.
    `fingerprint` - The namepool fingerprint of the function name. This must match the uri and localName; the information is provided redundantly to avoid repeated lookups in the name pool.

### bind

    public Expression bind(int nameCode,
                           String uri,
                           String local,
                           Expression[] staticArgs)
                    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:
    `nameCode` - The namepool nameCode of the function name. The uri and local name are also supplied (redundantly) to avoid fetching them from the name pool.
    `uri` - The URI of the function name
    `local` - The local part of the function name
    `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.
  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) Michael H. Kay. All rights reserved.