Using reflection

If you know what type an object is, you can use reflection to get information about the type or to perform actions on the object. Reflection means using type introspection to query or modify objects at run time. You can use reflection to retrieve metadata about classes, interfaces, fields, and methods at run time without knowing their names at compile time. You can also instantiate new objects and call methods with this information. For example, instead of calling an object method, you can get a list of methods from its type, or use a String runtime value to call a method by name.

Only use reflection if there is no other way to do what you need. Avoid using reflection to get properties or call methods. In almost all cases, you can write Gosu code to avoid reflection. Using reflection dramatically limits how Gosu and Guidewire Studio can alert you to problems at compile time. Detecting errors at compile time is better than encountering unexpected behavior at run time.

To use reflection from Java or Gosu, use the utility class gw.lang.reflect.ReflectUtil, which contains methods to retrieve information about a class, including its properties and methods, and other methods to invoke object methods.