- All Implemented Interfaces:
- Enclosing class:
public static class DynamicFunctionCallDefinition.DynamicFunctionCall
- extends ExtensionFunctionCall
- See Also:
- Serialized Form
|Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public Expression rewrite(StaticContext context,
- Rewrite the function call. This method is called at compile time. It gives the implementation
an opportunity to replace itself with an optimized implementation that returns the same result.
There is also an opportunity to perform static checking at this stage and to throw an error
if the arguments are invalid.
rewrite in class
context - The static context in which the function call appears. The method must not modify
the static context.
arguments - The XPath expressions supplied in the call to this function. This method is called
after type-checking, so these expressions may have been modified by adding atomization operators
or type-checking operations, for example.
- an expression to be evaluated at run-time in place of this function call. Return null
if no rewriting is required and the function call should be used unchanged. Return a
Literal representing the result of the function call if the function call
can be precomputed at compile time
XPathException - if the implementation is able to detect a static error in the way the
function is being called (for example it might require that the types of the arguments are
consistent with each other).
public SequenceIterator call(SequenceIterator arguments,
- Evaluate this function call at run-time
- Specified by:
call in class
arguments - The values of the arguments to the function call. Each argument value (which is in general
a sequence) is supplied in the form of an iterator over the items in the sequence. If required, the
supplied sequence can be materialized by calling, for example,
If the argument is always a singleton, then the single item may be obtained by calling
arguments[i].next(). The implementation is not obliged to read all the items in each
SequenceIterator if they are not required to compute the result; but if any SequenceIterator is not read
to completion, it is good practice to call its close() method.
context - The XPath dynamic evaluation context
- an iterator over the results of the function. If the result is a single item, it can be
returned in the form of a
SingletonIterator. If the result is an empty sequence,
the method should return
XPathException - if a dynamic error occurs during evaluation of the function. The Saxon run-time
code will add information about the error location.
Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.