net.sf.saxon.expr
Interface MappingFunction

All Known Implementing Classes:
AtomicSequenceConverter, Atomizer, Block, CardinalityChecker, Collection, DistinctValues, Document, ForEach, ForEachGroup, Id, Idref, InScopeNamespaces, ItemChecker, Key, ListType, PathExpression, Tokenize, TupleSorter, UntypedAtomicConverter

public interface MappingFunction

MappingFunction is an interface that must be satisfied by an object passed to a MappingIterator. It represents an object which, given an Item, can return a SequenceIterator that delivers a sequence of zero or more Items.


Method Summary
 java.lang.Object map(Item item, XPathContext context, java.lang.Object info)
          Map one item to a sequence.
 

Method Detail

map

public java.lang.Object map(Item item,
                            XPathContext context,
                            java.lang.Object info)
                     throws XPathException
Map one item to a sequence.

Parameters:
item - The item to be mapped. If context is supplied, this must be the same as context.currentItem().
context - The processing context. This is supplied only for mapping constructs that set the context node, position, and size. Otherwise it is null.
info - Arbitrary information supplied by the creator of the MappingIterator. It must be read-only and immutable for the duration of the iteration.
Returns:
either (a) a SequenceIterator over the sequence of items that the supplied input item maps to, or (b) an Item if it maps to a single item, or (c) null if it maps to an empty sequence.
XPathException