Package net.sf.saxon.expr

## Interface MappingFunction

- All Known Implementing Classes:
    `CompiledAxisMappingFunction`, `ForExpression.MappingAction`, `ForSequenceMappingAction`

      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.

  It maps an item of class F to a sequence of items of class T, returned as an iterator.

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `SequenceIterator` | `map​(Item item)` | Map one item to a sequence.

- - ### Method Detail

    - #### map

          SequenceIterator map​(Item item)
                        throws XPathException

      Map one item to a sequence.
      Parameters:
        `item` - The item to be mapped.
      Returns:
        one of the following: (a) a SequenceIterator over the sequence of items that the supplied input item maps to, or (b) null if it maps to an empty sequence.
      Throws:
        `XPathException` - if a dynamic error occurs