code: @Override
      public synchronized void setBeliefValue(String agent_name, String belief_name,
              Object new_value, Connector connector) {
          JadeAgentIntrospector.getInstance().dataToTest.get(agent_name).put(belief_name, new_value);
      }
docs: /* (non-Javadoc)
  @see es.upm.dit.gsi.beast.platform.AgentIntrospector#setBeliefValue(java.lang.String, java.lang.String, java.lang.Object, es.upm.dit.gsi.beast.platform.Connector)