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java.lang.Object net.sf.saxon.functions.IntegratedFunctionLibrary
public class IntegratedFunctionLibrary
A library of integrated function calls, that is, user-written extension functions implemented as instances of the class IntegratedFunction.
Constructor Summary | |
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IntegratedFunctionLibrary()
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Method Summary | |
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Expression |
bind(StructuredQName functionName,
Expression[] staticArgs,
StaticContext env,
Container container)
Bind an extension 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 system function with a given name and arity is available, and return its signature. |
Iterator<StructuredQName> |
iterateFunctionNames()
Return an iterator over the names of the functions registered in this library |
void |
registerFunction(ExtensionFunctionDefinition function)
Register an integrated function with 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 IntegratedFunctionLibrary()
Method Detail |
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public void registerFunction(ExtensionFunctionDefinition function)
function
- the implementation of the function (or set of functions)public SequenceType[] getFunctionSignature(StructuredQName functionName, int arity)
getFunctionSignature
in interface FunctionLibrary
functionName
- the name of the functionarity
- The number of arguments. This is set to -1 in the case of the single-argument
public Expression bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env, Container container) throws XPathException
bind
in interface FunctionLibrary
functionName
- the QName of the function being calledstaticArgs
- 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
- The static context of the function callcontainer
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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.public FunctionLibrary copy()
copy
in interface FunctionLibrary
public Iterator<StructuredQName> iterateFunctionNames()
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