Package io.grpc.util

Class ForwardingLoadBalancer

    • Constructor Detail

      • ForwardingLoadBalancer

        public ForwardingLoadBalancer()
    • Method Detail

      • delegate

        protected abstract LoadBalancer delegate()
        Returns the underlying balancer.
      • handleResolvedAddresses

        public void handleResolvedAddresses​(LoadBalancer.ResolvedAddresses resolvedAddresses)
        Description copied from class: LoadBalancer
        Handles newly resolved server groups and metadata attributes from name resolution system. servers contained in EquivalentAddressGroup should be considered equivalent but may be flattened into a single list if needed.

        Implementations should not modify the given servers.

        handleResolvedAddresses in class LoadBalancer
        resolvedAddresses - the resolved server addresses, attributes, and config.
      • handleNameResolutionError

        public void handleNameResolutionError​(Status error)
        Description copied from class: LoadBalancer
        Handles an error from the name resolution system.
        Specified by:
        handleNameResolutionError in class LoadBalancer
        error - a non-OK status
      • handleSubchannelState

        public void handleSubchannelState​(LoadBalancer.Subchannel subchannel,
                                          ConnectivityStateInfo stateInfo)
        Description copied from class: LoadBalancer
        Handles a state change on a Subchannel.

        The initial state of a Subchannel is IDLE. You won't get a notification for the initial IDLE state.

        If the new state is not SHUTDOWN, this method should create a new picker and call Helper.updateBalancingState(). Failing to do so may result in unnecessary delays of RPCs. Please refer to PickResult.withSubchannel()'s javadoc for more information.

        SHUTDOWN can only happen in two cases. One is that LoadBalancer called LoadBalancer.Subchannel.shutdown() earlier, thus it should have already discarded this Subchannel. The other is that Channel is doing a forced shutdown or has already terminated, thus there won't be further requests to LoadBalancer. Therefore, the LoadBalancer usually don't need to react to a SHUTDOWN state.

        handleSubchannelState in class LoadBalancer
        subchannel - the involved Subchannel
        stateInfo - the new state
      • shutdown

        public void shutdown()
        Description copied from class: LoadBalancer
        The channel asks the load-balancer to shutdown. No more methods on this class will be called after this method. The implementation should shutdown all Subchannels and OOB channels, and do any other cleanup as necessary.
        Specified by:
        shutdown in class LoadBalancer
      • requestConnection

        public void requestConnection()
        Description copied from class: LoadBalancer
        The channel asks the LoadBalancer to establish connections now (if applicable) so that the upcoming RPC may then just pick a ready connection without waiting for connections. This is triggered by ManagedChannel.getState(true).

        If LoadBalancer doesn't override it, this is no-op. If it infeasible to create connections given the current state, e.g. no Subchannel has been created yet, LoadBalancer can ignore this request.

        requestConnection in class LoadBalancer