public void update(Collection<String> expressions) {
            if (expressions == null || expressions.isEmpty()) {
                return;
            }

            FacesContext facesContext = getFacesContext();

            for (String expression : expressions) {

                if (LangUtils.isBlank(expression)) {
                    continue;
                }

                try {
                    String clientId =
                            SearchExpressionUtils.resolveClientId(facesContext, facesContext.getViewRoot(), expression);

                    facesContext.getPartialViewContext().getRenderIds().add(clientId);
                }
                catch (ComponentNotFoundException e) {
                    if (facesContext.isProjectStage(ProjectStage.Development)) {
                        LOGGER.log(Level.WARNING,
                                "PrimeFaces.current().ajax().update() called but component can not be resolved!"
                                + " Expression will just be added to the renderIds: {0}", expression);
                    }

                    facesContext.getPartialViewContext().getRenderIds().add(expression);
                }
            }
        }
Updates all components with the given expressions or clientIds.
{@link #ignoreAutoUpdate()} my be used additionally to ignoreAutoUpdate.

@param expressions a list of expressions or clientIds.
primefaces/src/main/java/org/primefaces/PrimeFaces.java