Package net.sf.saxon.functions

Class TreatFn

java.lang.Object
net.sf.saxon.functions.AbstractFunction
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.TreatFn
All Implemented Interfaces:
Callable, FunctionItem, GroundedValue, Item, Sequence
Direct Known Subclasses:
TreatFn.ExactlyOne, TreatFn.OneOrMore, TreatFn.ZeroOrOne
public abstract class TreatFn extends SystemFunction implements Callable
This class supports the XPath 2.0 functions exactly-one(), one-or-more(), zero-or-one(). Because Saxon doesn't do strict static type checking, these are essentially identity functions; the run-time type checking is done as part of the function call mechanism

  • Constructor Details

    • TreatFn

      public TreatFn()

  • Method Details

    • getErrorCodeForTypeErrors

      public abstract String getErrorCodeForTypeErrors()
      Return the error code to be used for type errors
      Overrides:
      getErrorCodeForTypeErrors in class SystemFunction
      Returns:
      the error code to be used for type errors in the function call. Normally XPTY0004, but different codes are used for functions such as exactly-one()

    • getRequiredCardinality

      public abstract int getRequiredCardinality()

    • call

      public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException
      Description copied from interface: Callable
      Call the Callable.
      Specified by:
      call in interface Callable
      Parameters:
      context - the dynamic evaluation context
      arguments - the values of the arguments, supplied as Sequences.

      Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

      If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

      It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

      Returns:
      the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.
      Throws:
      XPathException - if a dynamic error occurs during the evaluation of the expression

    • makeRoleDiagnostic

      public RoleDiagnostic makeRoleDiagnostic()

    • getStreamerName

      public String getStreamerName()
      Description copied from class: SystemFunction
      Get a name that identifies the class that can be used to evaluate this function in streaming mode, that is, supplying one item or event at a time as it is delivered by the parser. Special streaming support is generally available in Saxon-EE for all system functions that take a sequence as their argument.
      Overrides:
      getStreamerName in class SystemFunction
      Returns:
      a name that identifies a class that supports streamed evaluation of this system function, or null if no such class is available. The mapping of names to classes is defined in the Saxon-EE class StreamerMap. In non-streaming Saxon editions (HE and PE) the method always returns null.