docs: public boolean isCacheable(ExCache cache, Object target, Object[] arguments, Object result) throws Exception {
          if (null == cache || cache.expire() < 0 || cache.key().length() == 0) {
              return false;
          }
          boolean rv = true;
          if (null != cache.condition() && cache.condition().length() > 0) {
              rv = this.getElValue(cache.condition(), target, arguments, result, true, Boolean.class);
          }
          return rv;
      }