org.apache.druid.server.coordination

Enum ServerType

java.lang.Object

java.lang.Enum<ServerType>

org.apache.druid.server.coordination.ServerType

All Implemented Interfaces:

Serializable, Comparable<ServerType>

public enum ServerType
extends Enum<ServerType>

This enum represents types of druid services that hold segments.

These types are externally visible (e.g., from the output of ServersResource.makeSimpleServer(org.apache.druid.client.DruidServer)).

For backwards compatibility, when presenting these types externally, the toString() representation of the enum should be used.

The toString() method converts the enum name() to lowercase and replaces underscores with hyphens, which is the format expected for the server type string prior to the patch that introduced ServerType: https://github.com/apache/druid/pull/4148 This is a historical occasion that this enum is different from NodeRole because they are essentially the same abstraction, but merging them could only increase the complexity and drop the code safety, because they name the same types differently ("indexer-executor" - "peon" and "realtime" - "middleManager") and both expose them via JSON APIs. These abstractions can probably be merged when Druid updates to Jackson 2.9 that supports JsonAliases, see see https://github.com/apache/druid/issues/7152.

Enum Constant Summary

Enum Constants

Enum Constant and Description
BRIDGE
BROKER
HISTORICAL
INDEXER_EXECUTOR
REALTIME

Method Summary

Modifier and Type	Method and Description
static ServerType	fromString(String type)
boolean	isSegmentBroadcastTarget() Indicates this type of node is able to be a target of segment broadcast.
abstract boolean	isSegmentReplicationTarget() Indicates this type of node is able to be a target of segment replication.
abstract boolean	isSegmentServer() Indicates this type of node is serving segments that are meant to be the target of fan-out by a Broker.
String	toString()
static ServerType	valueOf(String name) Returns the enum constant of this type with the specified name.
static ServerType[]	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, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

HISTORICAL

public static final ServerType HISTORICAL

BRIDGE

public static final ServerType BRIDGE

INDEXER_EXECUTOR

public static final ServerType INDEXER_EXECUTOR

REALTIME

public static final ServerType REALTIME

BROKER

public static final ServerType BROKER

Method Detail

values

public static ServerType[] 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 (ServerType c : ServerType.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static ServerType 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

isSegmentReplicationTarget

public abstract boolean isSegmentReplicationTarget()

Indicates this type of node is able to be a target of segment replication.

Returns:

true if it is available for replication

See Also:

LoadRule

isSegmentBroadcastTarget

public boolean isSegmentBroadcastTarget()

Indicates this type of node is able to be a target of segment broadcast.

Returns:

true if it is available for broadcast.

isSegmentServer

public abstract boolean isSegmentServer()

Indicates this type of node is serving segments that are meant to be the target of fan-out by a Broker. Nodes that return "true" here are often referred to as "data servers" or "data server processes".

fromString

public static ServerType fromString(String type)

toString

public String toString()

Overrides:

toString in class Enum<ServerType>