net.sf.saxon.expr
Interface MappingFunction
- All Known Implementing Classes:
- AtomicSequenceConverter, Atomizer, CardinalityChecker, Collection, DistinctValues, Document, 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.
map
public Object map(Item item,
XPathContext context,
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.
- Throws:
XPathException