org.apache.ignite.internal.processors.cache.binary

Class MetadataUpdateProposedMessage

java.lang.Object

org.apache.ignite.internal.processors.cache.binary.MetadataUpdateProposedMessage

All Implemented Interfaces:

Serializable, DiscoveryCustomMessage

public final class MetadataUpdateProposedMessage
extends Object
implements DiscoveryCustomMessage

MetadataUpdateProposedMessage and MetadataUpdateAcceptedMessage messages make a basis for discovery-based protocol for exchanging metadata describing objects in binary format stored in Ignite caches. All interactions with binary metadata are performed through BinaryMetadataHandler interface implemented in CacheObjectBinaryProcessorImpl processor. Protocol works as follows:

1. Each thread aiming to add/update metadata sends MetadataUpdateProposedMessage and blocks until receiving acknowledge or reject for proposed update.
2. Coordinator node checks whether proposed update is in conflict with current version of metadata for the same typeId. In case of conflict initial MetadataUpdateProposedMessage is marked rejected and sent to initiator.
3. If there are no conflicts on coordinator, pending version for metadata of this typeId is bumped up by one; MetadataUpdateProposedMessage with pending version information is sent across the cluster.
4. Each node on receiving non-rejected MetadataUpdateProposedMessage updates pending version for the typeId in metadata local cache.
5. When MetadataUpdateProposedMessage finishes pass, ack is sent. Ack has the same accepted version as pending version of initial MetadataUpdateProposedMessage message.
6. Each node on receiving MetadataUpdateAcceptedMessage updates accepted version for the typeId. All threads waiting for arrival of ack with this accepted version are unblocked.

If a thread on some node decides to read metadata which has ongoing update (with pending version strictly greater than accepted version) it gets blocked until MetadataUpdateAcceptedMessage arrives with accepted version equals to pending version of this metadata to the moment when is was initially read by the thread.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MetadataUpdateProposedMessage(BinaryMetadata metadata, UUID origNodeId)

Method Summary

Methods

Modifier and Type	Method and Description
DiscoveryCustomMessage	ackMessage() Called when custom message has been handled by all nodes.
IgniteUuid	id()
boolean	isMutable()
BinaryMetadata	metadata()
void	metadata(BinaryMetadata metadata)
String	toString()
int	typeId()

Methods inherited from class java.lang.Object

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

Constructor Detail

MetadataUpdateProposedMessage

public MetadataUpdateProposedMessage(BinaryMetadata metadata,
                             UUID origNodeId)

Parameters:

metadata - BinaryMetadata requested to be updated.

origNodeId - ID of node requested update.

Method Detail

id

public IgniteUuid id()

Specified by:

id in interface DiscoveryCustomMessage

Returns:

Unique custom message ID.

ackMessage

@Nullable
public DiscoveryCustomMessage ackMessage()

Called when custom message has been handled by all nodes.

Specified by:

ackMessage in interface DiscoveryCustomMessage

Returns:

Ack message or null if ack is not required.

isMutable

public boolean isMutable()

Specified by:

isMutable in interface DiscoveryCustomMessage

Returns:

true if message can be modified during listener notification. Changes will be send to next nodes.

metadata

public BinaryMetadata metadata()

metadata

public void metadata(BinaryMetadata metadata)

Parameters:

metadata - Metadata.

typeId

public int typeId()

toString

public String toString()

Overrides:

toString in class Object