2 Replies Latest reply on Jan 15, 2007 5:11 AM by Andreas Franke

    Refresh entities

    Andreas Franke Apprentice

      How can I refresh entities in the following case.

      I have a page that contains:

      <div class="entry">
       <a4j:log hotkey="M" />
       <a4j:commandButton value="Reload" reRender="Sensor"/>
       <div class="label">Sensor:</div>
       <div class="input">
       <a4j:region renderRegionOnly="false">
       <h:selectOneMenu id="Sensor" value="#{messkette.sensor}"
       converter="#{selectItemHelfer}" required="true" disabled="#{gesperrt}">
       <f:selectItems value="#{messketteEditor.alleSensorenMitBlank}" />
       <a4j:support event="onchange" reRender="Funktion, Sensormessbereich, Einheit, Sensorwarnung" />
       </h:selectOneMenu>
       </a4j:region>
       <h:message for="Sensor" styleClass="message" />
       <div><h:outputText id="Sensorwarnung" value="#{messketteEditor.sensorWarnung}" styleClass="kursiv" /></div>
       </div>
       </div


      Sometimes I need to edit or create a entry from database in a second instance of web browser. So the list in messketteEditor has changed. But when I perform the Reload commandButton the outcome is the same with no changes.
      What I have to do tell the Entitymanger to refresh the list from database.

      Here the function that will be executet when a entity is changed or created
      public String speichern() {
      
       checkKorrekterAufruf();
      
       if (!vorSpeichern()) {
       ejbCtx.setRollbackOnly();
       return null;
       }
      
       try {
      
       String message = "";
      
       T entity = getEntity();
      
       if (neu) {
       //Neues Entity, anlegen
       em.persist(entity);
       message = angelegtMessage();
       loggeAenderung(getEntity(), "angelegt");
       } else {
       //Bestehendes Entity, Änderungen übernehmen
       setEntity(em.merge(entity));
       message = bearbeitetMessage();
       loggeAenderung(getEntity(), "bearbeitet");
       }
      
       nachSpeichern();System.out.println(entity);
      
       em.flush();
      
       addMessage(message);
      
       } catch (Exception ex) {
       ejbCtx.setRollbackOnly();
       addWarning(speichernError() + " " + exceptionListe(ex));
       System.out.println(ex.getMessage());
       ex.printStackTrace();
      
       return null;
       }
      
       return zurueckOutcome;
       }


      and this is the code to return the list
      private List<StandardEntity> listeHolen(Class<? extends StandardEntity> klasse, String where, String order) {
      
       String klassenName = klasse.getName();
      
       String query = "from " + klassenName;
       if (where != null)
       query += " where " + where;
       if (order != null)
       query += " order by " + order;
      
       List<StandardEntity> liste;
      
       try {
       liste = (List<StandardEntity>) em.createQuery(query).getResultList();
       } catch (Exception ex) {
       //Im Fehlerfall (z.B. nichts gefunden) leere Liste erzeugen
       ex.printStackTrace();
       liste = new Vector<StandardEntity>();
       }
      
       return liste;
       }


      Is there a solution for this case?


      Thanks
      andi