Module org.elasticsearch.server

Package org.elasticsearch.cluster.routing.allocation.decider

Interface Decision

All Superinterfaces:

ToXContent, Writeable

All Known Implementing Classes:

Decision.Multi, Decision.Single

public sealed interface Decision
extends ToXContent, Writeable
permits Decision.Single, Decision.Multi

A Decision used during shard allocation process.

See Also:

• AllocationDecider

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final record	Decision.Multi	Simple class representing a list of decisions
static final record	Decision.Single	Simple class representing a single decision
static enum	Decision.Type	This enumeration defines the possible types of decisions

Nested classes/interfaces inherited from interface org.elasticsearch.xcontent.ToXContent

ToXContent.DelegatingMapParams, ToXContent.MapParams, ToXContent.Params

Nested classes/interfaces inherited from interface org.elasticsearch.common.io.stream.Writeable

Writeable.Reader<V>, Writeable.Writer<V>

Field Summary

Fields

Modifier and Type	Field	Description
static final Decision.Single	ALWAYS
static final Decision.Single	NO
static final Decision.Single	NOT_PREFERRED
static final Decision.Single	THROTTLE
static final Decision.Single	YES

Fields inherited from interface org.elasticsearch.xcontent.ToXContent

EMPTY, EMPTY_PARAMS

Method Summary

Modifier and Type	Method	Description
List<Decision>	getDecisions()	Return the list of all decisions that make up this decision
String	getExplanation()	Get the explanation for this decision.
String	label()	Get the description label for this decision.
static Decision	readFrom(StreamInput in)
static Decision	single(Decision.Type type, String label, String explanation, Object... explanationParams)	Creates a new Decision instance including some (optional) extra details to explain it.
Decision.Type	type()	Get the Decision.Type of this decision

Methods inherited from interface org.elasticsearch.xcontent.ToXContent

isFragment, toXContent

Methods inherited from interface org.elasticsearch.common.io.stream.Writeable

writeTo

Field Details

ALWAYS

static final Decision.Single ALWAYS

YES

static final Decision.Single YES

NOT_PREFERRED

static final Decision.Single NOT_PREFERRED

NO

static final Decision.Single NO

THROTTLE

static final Decision.Single THROTTLE

Method Details

single

static Decision single(Decision.Type type,
 @Nullable
 String label,
 @Nullable
 String explanation,
 @Nullable
 Object... explanationParams)

Creates a new Decision instance including some (optional) extra details to explain it. Do not call this method to create a new Decision instance in an AllocationDecider implementation unless the explanation is required, because allocation decision-making is a hot path and constructing fresh instances for each decision can be very expensive. Instead, check RoutingAllocation.debugDecision() before doing nontrivial explanation work, and use one of the constants above such as YES or NO if no explanation is required. See also RoutingAllocation.decision(org.elasticsearch.cluster.routing.allocation.decider.Decision, java.lang.String, java.lang.String, java.lang.Object...) for a utility method to perform this check automatically.

Parameters:

type - Decision.Type of the decision

label - label for the Decider that produced this decision

explanation - explanation of the decision

explanationParams - additional parameters for the decision

Returns:

new Decision instance

readFrom

static Decision readFrom(StreamInput in)
                  throws IOException

Throws:

IOException

type

Decision.Type type()

Get the Decision.Type of this decision

Returns:

Decision.Type of this decision

label

@Nullable
String label()

Get the description label for this decision.

getExplanation

@Nullable
String getExplanation()

Get the explanation for this decision.

getDecisions

List<Decision> getDecisions()

Return the list of all decisions that make up this decision