Templates Exist API

Templates Exist Request

The Templates Exist API uses IndexTemplatesExistRequest as its request object. One or more index template names can be provided at construction.

IndexTemplatesExistRequest request;
request = new IndexTemplatesExistRequest("my-template"); 
request = new IndexTemplatesExistRequest("template-1", "template-2"); 
request = new IndexTemplatesExistRequest("my-*"); 

A single index template name

Multiple index template names

An index template name using wildcard

Optional arguments

request.setLocal(true); 
request.setMasterNodeTimeout(TimeValue.timeValueMinutes(1)); 
request.setMasterNodeTimeout("1m"); 

If true, reads templates from the node’s local cluster state. Otherwise reads from the cluster state of the elected master node

Timeout to connect to the master node as a TimeValue

Timeout to connect to the master node as a String

Synchronous Execution

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

boolean exists = client.indices().existsTemplate(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 IndexTemplatesExistRequest 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 templates-exist method:

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

The IndexTemplatesExistRequest 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 templates-exist looks like:

ActionListener<Boolean> listener = new ActionListener<Boolean>() {
    @Override
    public void onResponse(Boolean aBoolean) {
        
    }

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

Called when the execution is successfully completed.

Called when the whole IndexTemplatesExistRequest fails.

Response

The response is a Boolean value, true if any of the request’s template names match existing templates and false otherwise