add support for refreshAsync into ElasticsearchRestTemplate [DATAES-602]

[spring-projects-issues]

Fedor opened DATAES-602 and commented

Currently, ElasticsearchRestTemplate has API with sync refreshes only:

public void refresh(String indexName) {
...
 }
public <T> void refresh(Class<T> clazz) {
..
 }

However, _ Java High Level REST Client_ supports also refreshAsync, see https://www.elastic.co/guide/en/elasticsearch/client/java-rest/master/java-rest-high-refresh.html#java-rest-high-refresh-async

Executing a RefreshRequest 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 refresh method:

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

Pls, expose executing refreshes asynchronously in ElasticsearchRestTemplate

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No further details from DATAES-602

[spring-projects-issues]

sothawo commented

in version 4.0 it is possivle to do this with the following code:

@Autowired
ElasticsearchRestTemplate restTemplate;

RefreshRequest request = new RefreshRequest();
// prepare request

ActionListener<RefreshResponse> callback = new ActionListener<RefreshResponse>() {
    @Override
    public void onResponse(RefreshResponse refreshResponse) {
        // do something
    }

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

Cancellable cancellable = restTemplate.execute(client -> {
    return client.indices().refreshAsync(request, RequestOptions.DEFAULT, callback);
});