Get Field Mappings API

A GetFieldMappingsRequest can have an optional list of indices, optional list of types and the list of fields:

GetFieldMappingsRequest request = new GetFieldMappingsRequest(); 
request.indices("twitter"); 
request.fields("message", "timestamp"); 

The following arguments can also optionally be provided:

request.indicesOptions(IndicesOptions.lenientExpandOpen()); 

request.local(true); 

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

GetFieldMappingsResponse response =
    client.indices().getFieldMapping(request, requestOptions);

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 GetFieldMappingsRequest 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-field-mappings method:

client.indices().getFieldMappingAsync(request, requestOptions, 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 get-field-mappings looks like:

ActionListener<GetFieldMappingsResponse> listener =
    new ActionListener<GetFieldMappingsResponse>() {
        @Override
        public void onResponse(GetFieldMappingsResponse putMappingResponse) {
            
        }

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

The returned GetFieldMappingsResponse allows to retrieve information about the executed operation as follows:

final Map<String, Map<String, GetFieldMappingsResponse.FieldMappingMetadata>> mappings =
    response.mappings();
final Map<String, GetFieldMappingsResponse.FieldMappingMetadata> fieldMappings =
    mappings.get("twitter"); 
final GetFieldMappingsResponse.FieldMappingMetadata metadata =
    fieldMappings.get("message");

final String fullName = metadata.fullName();
final Map<String, Object> source = metadata.sourceAsMap();