Get Field Mappings API

Get Field Mappings Request

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"); 

An empty request

Setting the indices to fetch mapping for

The fields to be returned

Optional arguments

The following arguments can also optionally be provided:

request.indicesOptions(IndicesOptions.lenientExpandOpen()); 

Setting IndicesOptions controls how unavailable indices are resolved and how wildcard expressions are expanded

request.local(true); 

The local flag (defaults to false) controls whether the aliases need to be looked up in the local cluster state or in the cluster state held by the elected master node

Synchronous Execution

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.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 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.DEFAULT, listener); 

The GetFieldMappingsRequest 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-field-mappings looks like:

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

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

Called when the execution is successfully completed.

Called when the whole GetFieldMappingsRequest fails.

Get Field Mappings Response

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(); 

Returning all requested indices fields' mappings

Retrieving the mappings for a particular index

Getting the mappings metadata for the message field

Getting the full name of the field

Getting the mapping source of the field