Get Watch API

Execution

A watch can be retrieved as follows:

GetWatchRequest request = new GetWatchRequest("my_watch_id");

Response

The returned GetWatchResponse contains id, version, status and source information.

String watchId = response.getId(); 
boolean found = response.isFound(); 
long version = response.getVersion(); 
WatchStatus status = response.getStatus(); 
BytesReference source = response.getSource(); 

_id, id of the watch

found is a boolean indicating whether the watch was found

_version returns the version of the watch

status contains status of the watch

source the source of the watch

Synchronous Execution

When executing a GetWatchRequest in the following manner, the client waits for the GetWatchResponse to be returned before continuing with code execution:

GetWatchResponse response = client.watcher().getWatch(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

Executing a GetWatchRequest 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 get-watch method:

client.watcher().getWatchAsync(request, RequestOptions.DEFAULT, listener); 

The GetWatchRequest to execute and the ActionListener to use when the execution completes

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 get-watch looks like:

ActionListener<GetWatchResponse> listener = new ActionListener<GetWatchResponse>() {
    @Override
    public void onResponse(GetWatchResponse response) {
        
    }

    @Override
    public void onFailure(Exception e) {
        
    }
};

Called when the execution is successfully completed.

Called when the whole GetWatchRequest fails.