org.apache.camel.spi

Interface PollingConsumerPollStrategy

All Known Implementing Classes:

DefaultPollingConsumerPollStrategy, LimitedPollingConsumerPollStrategy

public interface PollingConsumerPollStrategy

Strategy for a PollingConsumer when polling an Endpoint.

This pluggable strategy allows to plugin different implementations what to do, most noticeable what to do in case the polling goes wrong. This can be handled in the rollback method.

Version:

Method Summary

Methods

Modifier and Type	Method and Description
boolean	begin(Consumer consumer, Endpoint endpoint) Called when poll is about to begin
void	commit(Consumer consumer, Endpoint endpoint, int polledMessages) Called when poll is completed successfully
boolean	rollback(Consumer consumer, Endpoint endpoint, int retryCounter, Exception cause) Called when poll failed

Method Detail

begin

boolean begin(Consumer consumer,
            Endpoint endpoint)

Called when poll is about to begin

Parameters:

consumer - the consumer

endpoint - the endpoint being consumed

Returns:

true to begin polling, or false to skip polling this time.

commit

void commit(Consumer consumer,
          Endpoint endpoint,
          int polledMessages)

Called when poll is completed successfully

Parameters:

consumer - the consumer

endpoint - the endpoint being consumed

polledMessages - number of messages polled, will be 0 if no message was polled at all.

rollback

boolean rollback(Consumer consumer,
               Endpoint endpoint,
               int retryCounter,
               Exception cause)
                 throws Exception

Called when poll failed

Parameters:

consumer - the consumer

endpoint - the endpoint being consumed

retryCounter - current retry attempt, starting from 0.

cause - the caused exception

Returns:

whether to retry immediately or not. Return false to ignore the problem, true to try immediately again

Throws:

Exception - can be used to rethrow the caused exception. Notice that thrown an exception will terminate the scheduler and thus Camel will not trigger again. So if you want to let the scheduler to continue to run then do not throw any exception from this method.