title: deleting all documents with out dropping index in elasticsearch java API
body: <p>Is there any simple Java API to delete all the documents from elastic search with out dropping the index. </p>
  
  <p>I know that we could get all the ids and delete each document one by one </p>
  
  <pre><code>DeleteResponse response = _client.prepareDelete(INDEX, TYPE, id)
              .setRefresh(true)
              .execute()
              .actionGet();
  </code></pre>
  
  <p>But I was looking for TRUNCATE kind of scenario. </p>
  
  <p>At present I am deleting the index and recreating the mapping in unit tests. </p>