com.hazelcast.jet.core

Enum Edge.RoutingPolicy

java.lang.Object

java.lang.Enum<Edge.RoutingPolicy>

com.hazelcast.jet.core.Edge.RoutingPolicy

All Implemented Interfaces:

Serializable, Comparable<Edge.RoutingPolicy>

Enclosing class:

Edge

public static enum Edge.RoutingPolicy
extends Enum<Edge.RoutingPolicy>
implements 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 and 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

Modifier and Type	Method and Description
static Edge.RoutingPolicy	valueOf(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(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