org.apache.kafka.clients
Class NetworkClient

java.lang.Object
  org.apache.kafka.clients.NetworkClient

All Implemented Interfaces:

KafkaClient

public class NetworkClient
extends java.lang.Object
implements KafkaClient

A network client for asynchronous request/response network i/o. This is an internal class used to implement the user-facing producer and consumer clients.

This class is not thread-safe!

Constructor Summary

NetworkClient(Selectable selector, Metadata metadata, java.lang.String clientId, int maxInFlightRequestsPerConnection, long reconnectBackoffMs, int socketSendBuffer, int socketReceiveBuffer)

Method Summary

void	close() Close the network client
int	inFlightRequestCount() Get the number of in-flight requests
boolean	isReady(Node node, long now) Check if the node with the given id is ready to send more requests.
Node	leastLoadedNode(long now) Choose the node with the fewest outstanding requests which is at least eligible for connection.
RequestHeader	nextRequestHeader(ApiKeys key) Generate a request header for the given API key
java.util.List<ClientResponse>	poll(java.util.List<ClientRequest> requests, long timeout, long now) Initiate the given requests and check for any new responses, waiting up to the specified time.
boolean	ready(Node node, long now) Begin connecting to the given node, return true if we are already connected and ready to send to that node.
void	wakeup() Interrupt the client if it is blocked waiting on I/O.

Methods inherited from class java.lang.Object

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

Constructor Detail

NetworkClient

public NetworkClient(Selectable selector,
                     Metadata metadata,
                     java.lang.String clientId,
                     int maxInFlightRequestsPerConnection,
                     long reconnectBackoffMs,
                     int socketSendBuffer,
                     int socketReceiveBuffer)

Method Detail

ready

public boolean ready(Node node,
                     long now)

Begin connecting to the given node, return true if we are already connected and ready to send to that node.

Specified by:

ready in interface KafkaClient

Parameters:

node - The node to check

now - The current timestamp

Returns:

True if we are ready to send to the given node

isReady

public boolean isReady(Node node,
                       long now)

Check if the node with the given id is ready to send more requests.

Specified by:

isReady in interface KafkaClient

Parameters:

node - The given node id

now - The current time in ms

Returns:

true if the node is ready

poll

public java.util.List<ClientResponse> poll(java.util.List<ClientRequest> requests,
                                           long timeout,
                                           long now)

Initiate the given requests and check for any new responses, waiting up to the specified time. Requests can only be sent for ready nodes.

Specified by:

poll in interface KafkaClient

Parameters:

requests - The requests to initiate

timeout - The maximum amount of time to wait (in ms) for responses if there are none immediately

now - The current time in milliseconds

Returns:

The list of responses received

inFlightRequestCount

public int inFlightRequestCount()

Get the number of in-flight requests

Specified by:

inFlightRequestCount in interface KafkaClient

nextRequestHeader

public RequestHeader nextRequestHeader(ApiKeys key)

Generate a request header for the given API key

Specified by:

nextRequestHeader in interface KafkaClient

Parameters:

key - The api key

Returns:

A request header with the appropriate client id and correlation id

wakeup

public void wakeup()

Interrupt the client if it is blocked waiting on I/O.

Specified by:

wakeup in interface KafkaClient

close

public void close()

Close the network client

Specified by:

close in interface KafkaClient

leastLoadedNode

public Node leastLoadedNode(long now)

Choose the node with the fewest outstanding requests which is at least eligible for connection. This method will prefer a node with an existing connection, but will potentially choose a node for which we don't yet have a connection if all existing connections are in use. This method will never choose a node for which there is no existing connection and from which we have disconnected within the reconnect backoff period.

Specified by:

leastLoadedNode in interface KafkaClient

Parameters:

now - The current time in ms

Returns:

The node with the fewest in-flight requests.