net.sf.saxon.functions

Interface Fold

All Known Implementing Classes:

FoldLeftFn.FoldLeftFold

public interface Fold

Method Summary

Modifier and Type	Method and Description
boolean	isFinished() Ask whether the computation has completed.
void	processItem(Item<?> item) Process one item in the input sequence, returning a new copy of the working data
Sequence<?>	result() Compute the final result of the function, when all the input has been processed

Method Detail

processItem

void processItem(Item<?> item)
          throws XPathException

Process one item in the input sequence, returning a new copy of the working data

Parameters:

item - the item to be processed from the input sequence

Throws:

XPathException - if a dynamic error occurs

isFinished

boolean isFinished()

Ask whether the computation has completed. A function that can deliver its final result without reading the whole input should return true; this will be followed by a call on result() to deliver the final result.

Returns:

true if the result of the function is now available even though not all items in the sequence have been processed

result

Sequence<?> result()
            throws XPathException

Compute the final result of the function, when all the input has been processed

Returns:

the result of the function

Throws:

XPathException - if a dynamic error occurs