Get Index API

Get Index Request

A GetIndexRequest requires one or more index arguments:

GetIndexRequest request = new GetIndexRequest("index"); 

The index whose information we want to retrieve

Optional arguments

The following arguments can optionally be provided:

request.includeDefaults(true); 

If true, defaults will be returned for settings not explicitly set on the index

request.indicesOptions(IndicesOptions.lenientExpandOpen()); 

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

Synchronous Execution

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

GetIndexResponse getIndexResponse = client.indices().get(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 GetIndexRequest 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-index method:

client.indices().getAsync(request, RequestOptions.DEFAULT, listener); 

The GetIndexRequest 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-index looks like:

ActionListener<GetIndexResponse> listener =
    new ActionListener<GetIndexResponse>() {
        @Override
        public void onResponse(GetIndexResponse getIndexResponse) {
            
        }

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

Called when the execution is successfully completed.

Called when the whole GetIndexRequest fails.

Get Index Response

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

MappingMetaData indexMappings = getIndexResponse.getMappings().get("index"); 
Map<String, Object> indexTypeMappings = indexMappings.getSourceAsMap(); 
List<AliasMetaData> indexAliases = getIndexResponse.getAliases().get("index"); 
String numberOfShardsString = getIndexResponse.getSetting("index", "index.number_of_shards"); 
Settings indexSettings = getIndexResponse.getSettings().get("index"); 
Integer numberOfShards = indexSettings.getAsInt("index.number_of_shards", null); 
TimeValue time = getIndexResponse.getDefaultSettings().get("index")
    .getAsTime("index.refresh_interval", null); 

Retrieve a Map of different types to MappingMetadata for index.

Retrieve a Map for the properties for document type doc.

Get the list of aliases for index.

Get the value for the setting string index.number_of_shards for index. If the setting was not explicitly specified but was part of the default settings (and includeDefault was true) then the default setting would be retrieved.

Retrieve all settings for index.

The Settings objects gives more flexibility. Here it is used to extract the setting index.number_of_shards as an integer.

Get the default setting index.refresh_interval (if includeDefault was set to true). If includeDefault was set to false, getIndexResponse.defaultSettings() will return an empty map.