code: private void initHistoryUpdaters() {
          historyUpdaters.put(RequestType.EXEC,
                              new HistoryUpdater<JmxExecRequest>() {
                                  /** {@inheritDoc} */
                                  public void updateHistory(JSONObject pJson,JmxExecRequest request, long pTimestamp) {
                                      HistoryEntry entry = historyStore.get(new HistoryKey(request));
                                      if (entry != null) {
                                          synchronized(entry) {
                                              pJson.put(KEY_HISTORY,entry.jsonifyValues());
                                              entry.add(pJson.get(KEY_VALUE),pTimestamp);
                                          }
                                      }
                                  }
                              });
          historyUpdaters.put(RequestType.WRITE,
                              new HistoryUpdater<JmxWriteRequest>() {
                                  /** {@inheritDoc} */
                                  public void updateHistory(JSONObject pJson,JmxWriteRequest request, long pTimestamp) {
                                      HistoryEntry entry = historyStore.get(new HistoryKey(request));
                                      if (entry != null) {
                                          synchronized(entry) {
                                              pJson.put(KEY_HISTORY,entry.jsonifyValues());
                                              entry.add(request.getValue(),pTimestamp);
                                          }
                                      }
                                  }
                              });
          historyUpdaters.put(RequestType.READ,
                              new HistoryUpdater<JmxReadRequest>() {
                                  /** {@inheritDoc} */
                                  public void updateHistory(JSONObject pJson,JmxReadRequest request, long pTimestamp) {
                                      updateReadHistory(request,pJson,pTimestamp);
                                  }
                              });
  
      }
docs: A set of updaters which are dispatched to for certain request types