Exists APIedit
The exists API returns true
if a document exists, and false
otherwise.
Exists Requestedit
It uses GetRequest
just like the Get API.
All of its optional arguments
are supported. Since exists()
only returns true
or false
, we recommend
turning off fetching _source
and any stored fields so the request is
slightly lighter:
Synchronous Executionedit
When executing a GetRequest
in the following manner, the client waits
for the boolean
to be returned before continuing with code execution:
boolean exists = client.exists(getRequest, RequestOptions.DEFAULT);
Asynchronous Executionedit
Executing a GetRequest
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 exists 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.
A typical listener for exists
looks like: