Find file structure API

A sample from the beginning of the file (or the entire file contents if it’s small) must be added to the FindFileStructureRequest object using the FindFileStructureRequest#setSample method.

FindFileStructureRequest findFileStructureRequest = new FindFileStructureRequest(); 
findFileStructureRequest.setSample(Files.readAllBytes(anInterestingFile)); 

The following arguments are optional.

findFileStructureRequest.setLinesToSample(500); 
findFileStructureRequest.setExplain(true); 

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

FindFileStructureResponse findFileStructureResponse =
    client.machineLearning().findFileStructure(findFileStructureRequest, 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.

Executing a FindFileStructureRequest 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 find-file-structure method:

client.machineLearning().findFileStructureAsync(findFileStructureRequest, RequestOptions.DEFAULT, listener); 

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 find-file-structure looks like:

ActionListener<FindFileStructureResponse> listener = new ActionListener<FindFileStructureResponse>() {
    @Override
    public void onResponse(FindFileStructureResponse findFileStructureResponse) {
        
    }

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

A FindFileStructureResponse contains information about the file structure, as well as mappings and an ingest pipeline that could be used to index the contents into Elasticsearch.

FileStructure structure = findFileStructureResponse.getFileStructure();