@GET @ApiIgnore // until documented
  @Produces("text/plain")
  public Response getStages(String body, @Context HttpHeaders headers, @Context UriInfo ui) {
    return handleRequest(headers, body, ui, Request.Type.GET,
        createStageResource(m_clusterName, m_requestId, null));
  }
Handles URL: /clusters/{clusterId}/requests/{requestID}/stages or /requests/{requestID}/stages
Get all stages for a request.

@param headers  http headers
@param ui       uri info

@return stage collection resource representation
ambari-server/src/main/java/org/apache/ambari/server/api/services/StageService.java