Enum ChainingStrategy

  • All Implemented Interfaces:
    Serializable, Comparable<ChainingStrategy>

    @PublicEvolving
    public enum ChainingStrategy
    extends Enum<ChainingStrategy>
    Defines the chaining scheme for the operator. When an operator is chained to the predecessor, it means that they run in the same thread. They become one operator consisting of multiple steps.

    The default value used by the StreamOperator is HEAD, which means that the operator is not chained to its predecessor. Most operators override this with ALWAYS, meaning they will be chained to predecessors whenever possible.

    • Enum Constant Detail

      • ALWAYS

        public static final ChainingStrategy ALWAYS
        Operators will be eagerly chained whenever possible.

        To optimize performance, it is generally a good practice to allow maximal chaining and increase operator parallelism.

      • NEVER

        public static final ChainingStrategy NEVER
        The operator will not be chained to the preceding or succeeding operators.
      • HEAD

        public static final ChainingStrategy HEAD
        The operator will not be chained to the predecessor, but successors may chain to this operator.
      • HEAD_WITH_SOURCES

        public static final ChainingStrategy HEAD_WITH_SOURCES
        This operator will run at the head of a chain (similar as in HEAD, but it will additionally try to chain source inputs if possible. This allows multi-input operators to be chained with multiple sources into one task.
    • Field Detail

      • DEFAULT_CHAINING_STRATEGY

        public static final ChainingStrategy DEFAULT_CHAINING_STRATEGY
    • Method Detail

      • values

        public static ChainingStrategy[] values()
        Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
        for (ChainingStrategy c : ChainingStrategy.values())
            System.out.println(c);
        
        Returns:
        an array containing the constants of this enum type, in the order they are declared
      • valueOf

        public static ChainingStrategy valueOf​(String name)
        Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
        Parameters:
        name - the name of the enum constant to be returned.
        Returns:
        the enum constant with the specified name
        Throws:
        IllegalArgumentException - if this enum type has no constant with the specified name
        NullPointerException - if the argument is null