Package net.sf.saxon.functions

Class Count

java.lang.Object
net.sf.saxon.functions.AbstractFunction
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.Count
All Implemented Interfaces:
Callable, FunctionItem, GroundedValue, Item, Sequence
public class Count extends SystemFunction
Implementation of the fn:count function

  • Constructor Details

    • Count

      public Count()

  • Method Details

    • getIntegerBounds

      public IntegerValue[] getIntegerBounds()
      For an expression that returns an integer or a sequence of integers, get a lower and upper bound on the values of the integers that may be returned, from static analysis. The default implementation returns null, meaning "unknown" or "not applicable". Other implementations return an array of two IntegerValue objects, representing the lower and upper bounds respectively. The values UNBOUNDED_LOWER and UNBOUNDED_UPPER are used by convention to indicate that the value may be arbitrarily large. The values MAX_STRING_LENGTH and MAX_SEQUENCE_LENGTH are used to indicate values limited by the size of a string or the size of a sequence.
      Overrides:
      getIntegerBounds in class SystemFunction
      Returns:
      the lower and upper bounds of integer values in the result, or null to indicate unknown or not applicable.

    • count

      public static int count(SequenceIterator iter) throws XPathException
      Get the number of items in a sequence identified by a SequenceIterator
      Parameters:
      iter - The SequenceIterator. This method moves the current position of the supplied iterator; if this isn't safe, make a copy of the iterator first by calling getAnother(). The supplied iterator must be positioned before the first item (there must have been no call on next()).
      Returns:
      the number of items in the underlying sequence
      Throws:
      XPathException - if a failure occurs reading the input sequence

    • steppingCount

      public static int steppingCount(SequenceIterator iter)
      Get the number of items in a sequence identified by a SequenceIterator
      Parameters:
      iter - The SequenceIterator. The supplied iterator must be positioned before the first item (there must have been no call on next()). It will always be consumed
      Returns:
      the number of items in the underlying sequence
      Throws:
      UncheckedXPathException - if a failure occurs reading the input sequence

    • call

      public IntegerValue call(XPathContext context, Sequence[] arguments) throws XPathException
      Evaluate the expression
      Parameters:
      context - the dynamic evaluation context
      arguments - the values of the arguments, supplied as Sequences
      Returns:
      the result of the evaluation, in the form of a Sequence
      Throws:
      XPathException - if a dynamic error occurs during the evaluation of the expression

    • 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.

    • getElaborator

      public Elaborator getElaborator()
      Make an elaborator for this expression
      Overrides:
      getElaborator in class SystemFunction
      Returns:
      a suitable elaborator