code: public String getToViewId(FacesContext context) {
  
          if (toViewIdExpr == null) {
              ExpressionFactory factory =
                    context.getApplication().getExpressionFactory();
              toViewIdExpr = factory.createValueExpression(context.getELContext(),
                                                           toViewId,
                                                           String.class);
          }
          String result = (String) toViewIdExpr.getValue(context.getELContext());
          if (result.charAt(0) != '/') {
              result = '/' + result;
          }
  
          return result;
  
      }
docs: <p class="changed_added_2_0">Evaluates the <code>&lt;to-view-id&gt;</code>
  for this <code>&lt;navigation-case&gt;</code></p>
  
  @param context the {@link FacesContext} for the current request
  
  @return the view ID that should be navigated to