Class Reverse

All Implemented Interfaces:
Callable, FunctionItem, GroundedValue, Item, Sequence

public class Reverse extends SystemFunction
Implement XPath function fn:reverse()
  • Constructor Details

    • Reverse

      public Reverse()
  • Method Details

    • getSpecialProperties

      public int getSpecialProperties(Expression[] arguments)
      Description copied from class: SystemFunction
      Determine the special properties of this function. The general rule is that a system function call is non-creative unless more details are defined in a subclass.
      Overrides:
      getSpecialProperties in class SystemFunction
      Parameters:
      arguments - the actual arguments supplied in a call to the function
      Returns:
      the properties
    • getReverseIterator

      public static SequenceIterator getReverseIterator(SequenceIterator forwards)
    • call

      public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException
      Description copied from interface: Callable
      Call the 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
    • makeOptimizedFunctionCall

      public Expression makeOptimizedFunctionCall(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo, Expression... arguments) throws XPathException
      Allow the function to create an optimized call based on the values of the actual arguments
      Overrides:
      makeOptimizedFunctionCall in class SystemFunction
      Parameters:
      visitor - the expression visitor
      contextInfo - information about the context item
      arguments - the supplied arguments to the function call. Note: modifying the contents of this array should not be attempted, it is likely to have no effect.
      Returns:
      either a function call on this function, or an expression that delivers the same result, or null indicating that no optimization has taken place
      Throws:
      XPathException - if an error is detected
    • reverseIterator

      public static <T extends Item> SequenceIterator reverseIterator(List<T> list)
    • 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.