Start watch service API
editStart watch service API
editExecution
editStart watcher enables you to manually start the watch service. Submit the following request to start the watch service:
StartWatchServiceRequest request = new StartWatchServiceRequest();
Response
editThe returned AcknowledgeResponse
contains a value on whether or not the request
was received:
Synchronous execution
editWhen executing a StartWatchServiceRequest
in the following manner, the client waits
for the StartWatchServiceResponse
to be returned before continuing with code execution:
AcknowledgedResponse response = client.watcher().startWatchService(request, RequestOptions.DEFAULT);
Synchronous calls may throw an IOException
in case of either failing to
parse the REST response in the high-level REST client, the request times out
or similar cases where there is no response coming back from the server.
In cases where the server returns a 4xx
or 5xx
error code, the high-level
client tries to parse the response body error details instead and then throws
a generic ElasticsearchException
and adds the original ResponseException
as a
suppressed exception to it.
Asynchronous execution
editExecuting a StartWatchServiceRequest
can also be done in an asynchronous fashion so that
the client can return directly. Users need to specify how the response or
potential failures will be handled by passing the request and a listener to the
asynchronous start-watch-service method:
The asynchronous method does not block and returns immediately. Once it is
completed the ActionListener
is called back using the onResponse
method
if the execution successfully completed or using the onFailure
method if
it failed. Failure scenarios and expected exceptions are the same as in the
synchronous execution case.
A typical listener for start-watch-service
looks like: