io.grpc

Class LoadBalancer<T>

java.lang.Object

io.grpc.LoadBalancer<T>

@ExperimentalApi
 @ThreadSafe
public abstract class LoadBalancer<T>
extends Object

A pluggable component that receives resolved addresses from NameResolver and provides the channel a usable transport when asked.

Note to implementations: all methods are expected to return quickly. Any work that may block should be done asynchronously.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LoadBalancer.Factory

Constructor Summary

Constructors

Constructor and Description
LoadBalancer()

Method Summary

Modifier and Type	Method and Description
void	handleNameResolutionError(Status error) Handles an error from the name resolution system.
void	handleResolvedAddresses(List<ResolvedServerInfo> servers, Attributes config) Handles newly resolved addresses and service config from name resolution system.
abstract ListenableFuture<T>	pickTransport(RequestKey requestKey) Pick a transport that Channel will use for next RPC.
void	shutdown() Shuts down this LoadBalancer.
void	transportReady(EquivalentAddressGroup addressGroup, T transport) Called when a transport is fully connected and ready to accept traffic.
void	transportShutdown(EquivalentAddressGroup addressGroup, T transport, Status s) Called when a transport is shutting down.

Methods inherited from class java.lang.Object

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

Constructor Detail

LoadBalancer

public LoadBalancer()

Method Detail

pickTransport

public abstract ListenableFuture<T> pickTransport(@Nullable
                                                  RequestKey requestKey)

Pick a transport that Channel will use for next RPC.

If the caller gives up before the futrue is done, it should call either cancel(true) or cancel(false) (they have the same effect) on the future to avoid leaking of resources.

Parameters:

requestKey - for affinity-based routing

shutdown

public void shutdown()

Shuts down this LoadBalancer.

handleResolvedAddresses

public void handleResolvedAddresses(List<ResolvedServerInfo> servers,
                                    Attributes config)

Handles newly resolved addresses and service config from name resolution system.

Implementations should not modify the given servers.

handleNameResolutionError

public void handleNameResolutionError(Status error)

Handles an error from the name resolution system.

Parameters:

error - a non-OK status

transportReady

public void transportReady(EquivalentAddressGroup addressGroup,
                           T transport)

Called when a transport is fully connected and ready to accept traffic.

transportShutdown

public void transportShutdown(EquivalentAddressGroup addressGroup,
                              T transport,
                              Status s)

Called when a transport is shutting down.