org.elasticsearch.cluster

Class ClusterState

java.lang.Object

org.elasticsearch.cluster.ClusterState

All Implemented Interfaces:

Diffable<ClusterState>, StreamableReader<ClusterState>, Writeable<ClusterState>, ToXContent

public class ClusterState
extends Object
implements ToXContent, Diffable<ClusterState>

Represents the current state of the cluster. The cluster state object is immutable with an exception of the RoutingNodes structure, which is built on demand from the RoutingTable, and cluster state status, which is updated during cluster state publishing and applying processing. The cluster state can be updated only on the master node. All updates are performed by on a single thread and controlled by the InternalClusterService. After every update the DiscoveryService.publish(org.elasticsearch.cluster.ClusterChangedEvent, org.elasticsearch.discovery.Discovery.AckListener) method publishes new version of the cluster state to all other nodes in the cluster. The actual publishing mechanism is delegated to the Discovery.publish(org.elasticsearch.cluster.ClusterChangedEvent, org.elasticsearch.discovery.Discovery.AckListener) method and depends on the type of discovery. For example, for local discovery it is implemented by the LocalDiscovery.publish(org.elasticsearch.cluster.ClusterChangedEvent, org.elasticsearch.discovery.Discovery.AckListener) method. In the Zen Discovery it is handled in the PublishClusterStateAction.publish(org.elasticsearch.cluster.ClusterChangedEvent, org.elasticsearch.discovery.Discovery.AckListener) method. The publishing mechanism can be overridden by other discovery. The cluster state implements the Diffable interface in order to support publishing of cluster state differences instead of the entire state on each change. The publishing mechanism should only send differences to a node if this node was present in the previous version of the cluster state. If a node is not present was not present in the previous version of the cluster state, such node is unlikely to have the previous cluster state version and should be sent a complete version. In order to make sure that the differences are applied to correct version of the cluster state, each cluster state version update generates stateUUID that uniquely identifies this version of the state. This uuid is verified by the ClusterStateDiff#apply method to makes sure that the correct diffs are applied. If uuids don’t match, the ClusterStateDiff#apply method throws the IncompatibleClusterStateVersionException, which should cause the publishing mechanism to send a full version of the cluster state to the node on which this exception was thrown.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ClusterState.Builder
static class	ClusterState.ClusterStateStatus
static interface	ClusterState.Custom
static class	ClusterState.Metric

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

ToXContent.DelegatingMapParams, ToXContent.MapParams, ToXContent.Params

Field Summary

Fields

Modifier and Type	Field and Description
static ClusterState	PROTO
static String	UNKNOWN_UUID
static long	UNKNOWN_VERSION

Fields inherited from interface org.elasticsearch.common.xcontent.ToXContent

EMPTY_PARAMS

Constructor Summary

Constructors

Constructor and Description
ClusterState(ClusterName clusterName, long version, String stateUUID, MetaData metaData, RoutingTable routingTable, DiscoveryNodes nodes, ClusterBlocks blocks, ImmutableOpenMap<String,ClusterState.Custom> customs, boolean wasReadFromDiff)
ClusterState(long version, String stateUUID, ClusterState state)

Method Summary

Methods

Modifier and Type	Method and Description
ClusterBlocks	blocks()
static ClusterState.Builder	builder(ClusterName clusterName)
static ClusterState.Builder	builder(ClusterState state)
<T extends ClusterState.Custom> T	custom(String type)
ImmutableOpenMap<String,ClusterState.Custom>	customs()
Diff	diff(ClusterState previousState) Returns serializable object representing differences between this and previousState
ClusterBlocks	getBlocks()
ClusterName	getClusterName()
ImmutableOpenMap<String,ClusterState.Custom>	getCustoms()
MetaData	getMetaData()
DiscoveryNodes	getNodes()
RoutingNodes	getRoutingNodes() Returns a built (on demand) routing nodes view of the routing table.
RoutingTable	getRoutingTable()
long	getVersion()
static <T extends ClusterState.Custom> T	lookupPrototype(String type)
static <T extends ClusterState.Custom> T	lookupPrototypeSafe(String type)
MetaData	metaData()
DiscoveryNodes	nodes()
String	prettyPrint()
Diff<ClusterState>	readDiffFrom(StreamInput in) Reads the Diff from StreamInput
ClusterState	readFrom(StreamInput in) Reads a copy of an object with the same type form the stream input The caller object remains unchanged.
ClusterState	readFrom(StreamInput in, DiscoveryNode localNode)
static void	registerPrototype(String type, ClusterState.Custom proto) Register a custom index meta data factory.
RoutingTable	routingTable()
String	stateUUID() This stateUUID is automatically generated for for each version of cluster state.
ClusterState.ClusterStateStatus	status()
ClusterState	status(ClusterState.ClusterStateStatus newStatus)
String	toString()
XContentBuilder	toXContent(XContentBuilder builder, ToXContent.Params params)
long	version()
void	writeTo(StreamOutput out) Writes the current object into the output stream out

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

PROTO

public static final ClusterState PROTO

UNKNOWN_UUID

public static final String UNKNOWN_UUID

See Also:

Constant Field Values

UNKNOWN_VERSION

public static final long UNKNOWN_VERSION

See Also:

Constant Field Values

Constructor Detail

ClusterState

public ClusterState(long version,
            String stateUUID,
            ClusterState state)

ClusterState

public ClusterState(ClusterName clusterName,
            long version,
            String stateUUID,
            MetaData metaData,
            RoutingTable routingTable,
            DiscoveryNodes nodes,
            ClusterBlocks blocks,
            ImmutableOpenMap<String,ClusterState.Custom> customs,
            boolean wasReadFromDiff)

Method Detail

registerPrototype

public static void registerPrototype(String type,
                     ClusterState.Custom proto)

Register a custom index meta data factory. Make sure to call it from a static block.

lookupPrototype

@Nullable
public static <T extends ClusterState.Custom> T lookupPrototype(String type)

lookupPrototypeSafe

public static <T extends ClusterState.Custom> T lookupPrototypeSafe(String type)

status

public ClusterState.ClusterStateStatus status()

status

public ClusterState status(ClusterState.ClusterStateStatus newStatus)

version

public long version()

getVersion

public long getVersion()

stateUUID

public String stateUUID()

This stateUUID is automatically generated for for each version of cluster state. It is used to make sure that we are applying diffs to the right previous state.

nodes

public DiscoveryNodes nodes()

getNodes

public DiscoveryNodes getNodes()

metaData

public MetaData metaData()

getMetaData

public MetaData getMetaData()

routingTable

public RoutingTable routingTable()

getRoutingTable

public RoutingTable getRoutingTable()

blocks

public ClusterBlocks blocks()

getBlocks

public ClusterBlocks getBlocks()

customs

public ImmutableOpenMap<String,ClusterState.Custom> customs()

getCustoms

public ImmutableOpenMap<String,ClusterState.Custom> getCustoms()

custom

public <T extends ClusterState.Custom> T custom(String type)

getClusterName

public ClusterName getClusterName()

getRoutingNodes

public RoutingNodes getRoutingNodes()

Returns a built (on demand) routing nodes view of the routing table.

prettyPrint

public String prettyPrint()

toString

public String toString()

Overrides:

toString in class Object

toXContent

public XContentBuilder toXContent(XContentBuilder builder,
                         ToXContent.Params params)
                           throws IOException

Specified by:

toXContent in interface ToXContent

Throws:

IOException

builder

public static ClusterState.Builder builder(ClusterName clusterName)

builder

public static ClusterState.Builder builder(ClusterState state)

diff

public Diff diff(ClusterState previousState)

Description copied from interface: Diffable

Returns serializable object representing differences between this and previousState

Specified by:

diff in interface Diffable<ClusterState>

readDiffFrom

public Diff<ClusterState> readDiffFrom(StreamInput in)
                                throws IOException

Description copied from interface: Diffable

Reads the Diff from StreamInput

Specified by:

readDiffFrom in interface Diffable<ClusterState>

Throws:

IOException

readFrom

public ClusterState readFrom(StreamInput in,
                    DiscoveryNode localNode)
                      throws IOException

Throws:

IOException

readFrom

public ClusterState readFrom(StreamInput in)
                      throws IOException

Description copied from interface: StreamableReader

Reads a copy of an object with the same type form the stream input The caller object remains unchanged.

Specified by:

readFrom in interface StreamableReader<ClusterState>

Throws:

IOException

writeTo

public void writeTo(StreamOutput out)
             throws IOException

Description copied from interface: Writeable

Writes the current object into the output stream out

Specified by:

writeTo in interface Writeable<ClusterState>

Throws:

IOException