Package com.hazelcast.jet.core

Enum Edge.RoutingPolicy

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<Edge.RoutingPolicy>
    Enclosing class:
    Edge
    public static enum Edge.RoutingPolicy
extends java.lang.Enum<Edge.RoutingPolicy>
implements java.io.Serializable
    An edge describes a connection from many upstream processors to many downstream processors. The routing policy decides where exactly to route each particular item emitted from an upstream processor. To simplify the reasoning we introduce the concept of the set of candidate downstream processors, or the candidate set for short. On a local edge the candidate set contains only local processors and on a distributed edge it contains all the processors.

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description
      BROADCAST
      This policy sends each item to all candidate processors.
      FANOUT
      This policy sends an item to all members, but only to one processor on each member.
      ISOLATED
      This policy sets up isolated parallel data paths between two vertices as much as it can, given the level of mismatch between the local parallelism (LP) of the upstream vs.
      PARTITIONED
      This policy sends every item to the one processor responsible for the item's partition ID.
      UNICAST
      This policy chooses for each item a single destination processor from the candidate set, with no restriction on the choice.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static Edge.RoutingPolicy valueOf​(java.lang.String name)
      Returns the enum constant of this type with the specified name.
      static Edge.RoutingPolicy[] values()
      Returns an array containing the constants of this enum type, in the order they are declared.

      • Methods inherited from class java.lang.Enum

        clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

      • Methods inherited from class java.lang.Object

        getClass, notify, notifyAll, wait, wait, wait

    • Enum Constant Detail

      • UNICAST

        public static final Edge.RoutingPolicy UNICAST
        This policy chooses for each item a single destination processor from the candidate set, with no restriction on the choice.

      • ISOLATED

        public static final Edge.RoutingPolicy ISOLATED
        This policy sets up isolated parallel data paths between two vertices as much as it can, given the level of mismatch between the local parallelism (LP) of the upstream vs. the downstream vertices. Specifically:
        • If LP_upstream <= LP_downstream, every downstream processor receives data from only one upstream processor
        • If LP_upstream >= LP_downstream, every upstream processor sends data to only one downstream processor
        If LP_upstream = LP_downstream, both of the above are true and there are isolated pairs of upstream and downstream processors.

        This policy is only available on a local edge.

      • PARTITIONED

        public static final Edge.RoutingPolicy PARTITIONED
        This policy sends every item to the one processor responsible for the item's partition ID. On a distributed edge, this processor is unique across the cluster; on a non-distributed edge, the processor is unique only within a member.

      • BROADCAST

        public static final Edge.RoutingPolicy BROADCAST
        This policy sends each item to all candidate processors.

      • FANOUT

        public static final Edge.RoutingPolicy FANOUT
        This policy sends an item to all members, but only to one processor on each member. It's a combination of BROADCAST and UNICAST: an item is first broadcast to all members, and then, on each member, it is unicast to one processor.

        If the destination local parallelism is 1, the behavior is equal to BROADCAST. If the member count in the cluster is 1, the behavior is equal to UNICAST.

        To work as expected, the edge must be also Edge.distributed(). Otherwise it will work just like UNICAST.

        Since:
        Jet 4.4

    • Method Detail

      • values

        public static Edge.RoutingPolicy[] 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 (Edge.RoutingPolicy c : Edge.RoutingPolicy.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static Edge.RoutingPolicy valueOf​(java.lang.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:
        java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
        java.lang.NullPointerException - if the argument is null