net.kuujo.catalog.client

Class RaftClient

java.lang.Object

net.kuujo.catalog.client.RaftClient

All Implemented Interfaces:

net.kuujo.catalyst.util.Managed<RaftClient>

public class RaftClient
extends Object
implements net.kuujo.catalyst.util.Managed<RaftClient>

Raft client.

Author:

Jordan Halterman

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RaftClient.Builder Raft client builder.

Method Summary

Modifier and Type	Method and Description
static RaftClient.Builder	builder(net.kuujo.catalyst.transport.Address... members) Returns a new Raft client builder.
static RaftClient.Builder	builder(Collection<net.kuujo.catalyst.transport.Address> members) Returns a new Raft client builder.
CompletableFuture<Void>	close()
net.kuujo.catalyst.util.concurrent.Context	context() Returns the client execution context.
boolean	isClosed()
boolean	isOpen()
CompletableFuture<RaftClient>	open()
Session	session() Returns the client session.
<T> CompletableFuture<T>	submit(Command<T> command) Submits a command to the Raft cluster.
<T> CompletableFuture<T>	submit(Operation<T> operation) Submits an operation to the Raft cluster.
<T> CompletableFuture<T>	submit(Query<T> query) Submits a query to the Raft cluster.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

builder

public static RaftClient.Builder builder(net.kuujo.catalyst.transport.Address... members)

Returns a new Raft client builder.

The provided set of members will be used to connect to the Raft cluster. The members list does not have to represent the complete list of servers in the cluster, but it must have at least one reachable member.

Parameters:

members - The cluster members to which to connect.

Returns:

The client builder.

builder

public static RaftClient.Builder builder(Collection<net.kuujo.catalyst.transport.Address> members)

Returns a new Raft client builder.

The provided set of members will be used to connect to the Raft cluster. The members list does not have to represent the complete list of servers in the cluster, but it must have at least one reachable member.

Parameters:

members - The cluster members to which to connect.

Returns:

The client builder.

context

public net.kuujo.catalyst.util.concurrent.Context context()

Returns the client execution context.

The execution context is the event loop that this client uses to communicate Raft servers. Implementations must guarantee that all asynchronous CompletableFuture callbacks are executed on a single thread via the returned Context.

The Context can also be used to access the Raft client's internal serializer via Context.serializer().

Returns:

The Raft context.

session

public Session session()

Returns the client session.

The returned Session instance will remain constant throughout the lifetime of this client. Once the instance is opened, the session will have been registered with the Raft cluster and listeners registered via Session.onOpen(java.util.function.Consumer) will be called. In the event of a session expiration, listeners registered via Session.onClose(java.util.function.Consumer) will be called.

Returns:

The client session.

submit

public <T> CompletableFuture<T> submit(Operation<T> operation)

Submits an operation to the Raft cluster.

This method is provided for convenience. The submitted Operation must be an instance of Command or Query.

Type Parameters:

T - The operation result type.

Parameters:

operation - The operation to submit.

Returns:

A completable future to be completed with the operation result.

Throws:

IllegalArgumentException - If the Operation is not an instance of Command or Query.

NullPointerException - if operation is null

submit

public <T> CompletableFuture<T> submit(Command<T> command)

Submits a command to the Raft cluster.

Commands are used to alter state machine state. All commands will be forwarded to the current Raft leader. Once a leader receives the command, it will write the command to its internal Log and replicate it to a majority of the cluster. Once the command has been replicated to a majority of the cluster, it will apply the command to its state machine and respond with the result.

Once the command has been applied to a server state machine, the returned CompletableFuture will be completed with the state machine output.

Type Parameters:

T - The command result type.

Parameters:

command - The command to submit.

Returns:

A completable future to be completed with the command result.

Throws:

NullPointerException - if command is null

submit

public <T> CompletableFuture<T> submit(Query<T> query)

Submits a query to the Raft cluster.

Queries are used to read state machine state. The behavior of query submissions is primarily dependent on the query's ConsistencyLevel. For ConsistencyLevel.LINEARIZABLE and ConsistencyLevel.LINEARIZABLE_LEASE consistency levels, queries will be forwarded to the Raft leader. For lower consistency levels, queries are allowed to read from followers. All queries are executed by applying queries to an internal server state machine.

Once the query has been applied to a server state machine, the returned CompletableFuture will be completed with the state machine output.

Type Parameters:

T - The query result type.

Parameters:

query - The query to submit.

Returns:

A completable future to be completed with the query result.

Throws:

NullPointerException - if query is null

open

public CompletableFuture<RaftClient> open()

Specified by:

open in interface net.kuujo.catalyst.util.Managed<RaftClient>

isOpen

public boolean isOpen()

Specified by:

isOpen in interface net.kuujo.catalyst.util.Managed<RaftClient>

close

public CompletableFuture<Void> close()

Specified by:

close in interface net.kuujo.catalyst.util.Managed<RaftClient>

isClosed

public boolean isClosed()

Specified by:

isClosed in interface net.kuujo.catalyst.util.Managed<RaftClient>