code: public void deleteIndex(String indexName, String designDocId, String type) {
          assertNotEmpty(indexName, "indexName");
          assertNotEmpty(designDocId, "designDocId");
          assertNotNull(type, "type");
          if (!designDocId.startsWith("_design")) {
              designDocId = "_design/" + designDocId;
          }
          URI uri = new DatabaseURIHelper(db.getDBUri()).path("_index").path(designDocId)
                  .path(type).path(indexName).build();
          InputStream response = null;
          try {
              HttpConnection connection = Http.DELETE(uri);
              response = client.couchDbClient.executeToInputStream(connection);
              getResponse(response, Response.class, client.getGson());
          } finally {
              close(response);
          }
      }
docs: Delete an index with the specified name and type in the given design document.
  
  @param indexName   name of the index
  @param designDocId ID of the design doc (the _design prefix will be added if not present)
  @param type        type of the index, valid values or "text" or "json"