code: private void evaluateExpressions() throws JspException {
          Object obj = null;
  
          /* 
           * Note: we don't check for type mismatches here; we assume
           * the expression evaluator will return the expected type
           * (by virtue of knowledge we give it about what that type is).
           * A ClassCastException here is truly unexpected, so we let it
           * propagate up.
           */
  
          // 'value' attribute
          if (value_ != null) {
              value = (String) ExpressionEvaluatorManager.evaluate(
                      "value", value_, String.class, this, pageContext);
          }
  
          // 'type' attribute
          if (type_ != null) {
              type = (String) ExpressionEvaluatorManager.evaluate(
                      "type", type_, String.class, this, pageContext);
          }
  
          // 'pattern' attribute
          if (pattern_ != null) {
              pattern = (String) ExpressionEvaluatorManager.evaluate(
                      "pattern", pattern_, String.class, this, pageContext);
          }
  
          // 'parseLocale' attribute
          if (parseLocale_ != null) {
              obj = ExpressionEvaluatorManager.evaluate(
                      "parseLocale", parseLocale_, Object.class, this, pageContext);
              Locale locale = LocaleUtil.parseLocaleAttributeValue(obj);
              if (locale != null) {
                  this.parseLocale = locale;
              }
          }
  
          // 'integerOnly' attribute
          if (integerOnly_ != null) {
              obj = ExpressionEvaluatorManager.evaluate(
                      "integerOnly", integerOnly_, Boolean.class, this, pageContext);
              if (obj != null) {
                  isIntegerOnly = ((Boolean) obj).booleanValue();
              }
          }
      }
docs: Evaluates expressions as necessary