Package org.apache.cassandra.cql3.functions

Interface ScalarFunction

All Superinterfaces:
AssignmentTestable, Function
All Known Subinterfaces:
PartialScalarFunction
All Known Implementing Classes:
BytesConversionFcts.FromBlobFunction, BytesConversionFcts.ToBlobFunction, DefaultMaskingFunction, FromJsonFct, HashMaskingFunction, JavaBasedUDFunction, MaskingFunction, NativeScalarFunction, NullMaskingFunction, PartialMaskingFunction, ReplaceMaskingFunction, TimeFcts.FloorDateFunction, TimeFcts.FloorTimestampFunction, TimeFcts.FloorTimeUuidFunction, TimeFcts.TemporalConversionFunction, ToJsonFct, TokenFct, UDFunction
public interface ScalarFunction extends Function
Determines a single output value based on any number of input values.

  • Method Details

    • isCalledOnNullInput

      boolean isCalledOnNullInput()

    • isMonotonic

      default boolean isMonotonic()
      Checks if the function is monotonic.

      A function is monotonic if it is either entirely nonincreasing or nondecreasing given an ordered set of inputs.

      Returns:
      true if the function is monotonic false otherwise.

    • execute

      ByteBuffer execute(Arguments arguments) throws InvalidRequestException
      Applies this function to the specified arguments.
      Parameters:
      arguments - the input arguments for the function
      Returns:
      the result of applying this function to the arguments
      Throws:
      InvalidRequestException - if this function cannot not be applied to the arguments

    • partialApplication

      default ScalarFunction partialApplication(ProtocolVersion protocolVersion, List<ByteBuffer> partialArguments)
      Does a partial application of the function. That is, given only some of the arguments of the function provided, return a new function that only expect the arguments not provided.

      To take an example, if you consider the function 

           text foo(int a, text b, text c, int d)
      then foo.partialApplication([3, <ommitted>, 'bar', <omitted>]) will return a function bar of signature: 
           text bar(text b, int d)
      and such that for any value of b and d, bar(b, d) == foo(3, b, 'bar', d).
      Parameters:
      protocolVersion - protocol version used for arguments
      partialArguments - a list of input arguments for the function where some arguments can be Function.UNRESOLVED. The input must be of size this.argsType().size(). For convenience, it is allowed both to pass a list with all arguments being Function.UNRESOLVED (the function is then returned directly) and with none of them unresolved (in which case, if the function is pure, it is computed and a dummy no-arg function returning the result is returned).
      Returns:
      a function corresponding to the partial application of this function to the arguments of partialArguments that are not Function.UNRESOLVED.