Class ImportedFunctionLibrary

java.lang.Object
net.sf.saxon.query.ImportedFunctionLibrary
All Implemented Interfaces:
Serializable, FunctionLibrary, XQueryFunctionBinder

public class ImportedFunctionLibrary extends Object implements FunctionLibrary, XQueryFunctionBinder
This implementation of FunctionLibrary contains all the functions imported into a Query Module. It is implemented as a view of the "global" XQueryFunctionLibrary for the whole query, selecting only those functions that are in an imported namespace.
See Also:
  • Constructor Details

    • ImportedFunctionLibrary

      public ImportedFunctionLibrary(QueryModule importingModule, XQueryFunctionLibrary baseLibrary)
      Create an imported function library
      Parameters:
      importingModule - the module importing the library
      baseLibrary - the function library of which this is a subset view
  • Method Details

    • addImportedNamespace

      public void addImportedNamespace(String namespace)
      Add an imported namespace
      Parameters:
      namespace - the imported namespace
    • bind

      public Expression bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env) throws XPathException
      Bind an extension 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 - the name of the function to be bound
      staticArgs - The expressions supplied statically in arguments to the function call. The length of this array represents the arity of the function. 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 -
      Returns:
      An object representing the function to be called, if one is found; null if no 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.
    • getDeclaration

      public XQueryFunction getDeclaration(StructuredQName functionName, Expression[] staticArgs)
      Get the function declaration corresponding to a given function name and arity
      Specified by:
      getDeclaration in interface XQueryFunctionBinder
      Parameters:
      functionName - the name of the function as a QName
      staticArgs - the expressions supplied as arguments in the function call (typically, we only need to know the number of arguments)
      Returns:
      the XQueryFunction if there is one, or null if not.
    • 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.
    • setImportingModule

      public void setImportingModule(QueryModule importingModule)
      Set the module that imports this function libary
      Parameters:
      importingModule - the importing module
    • isAvailable

      public boolean isAvailable(StructuredQName functionName, int arity)
      Test whether an extension function with a given name and arity is available. This supports the function-available() function in XSLT. 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:
      isAvailable in interface FunctionLibrary
      Parameters:
      functionName - the name of the function in question
      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
      Returns:
      true if a function of this name and arity is available for calling.