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java.lang.Object net.sf.saxon.functions.ExecutableFunctionLibrary
public class ExecutableFunctionLibrary
An ExecutableFunctionLibrary is a function library that contains definitions of functions for use at run-time. Normally functions are bound at compile-time; however there are various situations in which the information is needed dynamically, for example (a) to support the XSLT function-available() call (in the pathological case where the argument is not known statically), (b) to allow functions to be called from saxon:evaluate(), (c) to allow functions to be called from a debugging breakpoint. The objects actually held in the ExecutableFunctionLibrary are UserFunctionCall objects that have been prepared at compile time. These are function calls that do full dynamic type checking: that is, they are prepared on the basis that the static types of the arguments are all "item()*", meaning that full type checking is needed at run-time.
Constructor Summary | |
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ExecutableFunctionLibrary(Configuration config)
Create the ExecutableFunctionLibrary |
Method Summary | |
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void |
addFunction(UserFunction fn)
Register a function with the function library |
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. |
Iterator<UserFunction> |
iterateFunctions()
Iterate over all the functions defined in this function library. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public ExecutableFunctionLibrary(Configuration config)
config
- the Saxon configurationMethod Detail |
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public void addFunction(UserFunction fn)
fn
- the function to be registeredpublic SequenceType[] getFunctionSignature(StructuredQName functionName, int arity)
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.
getFunctionSignature
in interface FunctionLibrary
functionName
- the qualified name of the function being calledarity
- 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.
public Expression bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env, Container container) throws XPathException
bind
in interface FunctionLibrary
functionName
- The name of the function to be calledstaticArgs
- 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
- the static evaluation contextcontainer
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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.public FunctionLibrary copy()
copy
in interface FunctionLibrary
public Iterator<UserFunction> iterateFunctions()
UserFunction
UserFunction
objects representing
the user-defined functions in a stylesheet or query
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