| Nasgen is a tool for processing Java classes that implement native |
| JavaScript objects. It does so by looking for the |
| com.oracle.nashorn.objects.annotations.ScriptClass annotation and other |
| annotations in that package. |
| |
| For each class "C", nasgen instruments the original class and generates |
| two additional classes: a "C$Prototype" class for the JavaScript |
| prototype object, and a "C$Constructor" class for the JavaScript |
| constructor function. |
| |
| Each class instrumented or generated by nasgen contains a private static |
| "$nasgenmap$" field of type com.oracle.nashorn.runtime.PropertyMap and |
| static initializer block to initialize the field to the object's |
| JavaScript properties. |
| |
| Members annotated with @Function, @Property, @Getter, and @Setter are |
| mapped to the $Constructor, $Prototype, or main class, depending on the |
| value of the annotation's 'where' field. By default, @Property, @Getter, |
| and @Setter belong to the main class while @Function methods without |
| explicit 'where' field belong to the $Prototype class. The @Constructor |
| annotation marks a method to be invoked as JavaScript constructor. |
| |
| Nasgen enforces all @Function/@Getter/@Setter/@Constructor annotated |
| methods to be declared as static. Static final @Property fields remain |
| in the main class while other @Property fields are moved to respective |
| classes depending on the annotation's 'where' value. For functions |
| mapped to the $Prototype or $Constructor class, nasgen also generates |
| getters and setters prefixed by G$ and S$, respectively. |
| |
| Nasgen-generated classes are hidden from normal ClassLoaders by giving |
| them a ".clazz" file name extension instead of the standard ".class" |
| extension. This allows script classes to be loaded independently by each |
| Nashorn context through the com.oracle.nashorn.runtime.StructureLoader |
| class loader. |
