Mercurial > jdk8-mips64-public > nashorn / annotate
buildtools/nasgen/README@905b35451b21 (annotated)
buildtools/nasgen/README
Tue, 06 Jun 2017 10:03:12 -0700
- author
- asaha
- date
- Tue, 06 Jun 2017 10:03:12 -0700
- changeset 2063
- 905b35451b21
- parent 0
- b1a7da25b547
- permissions
- -rw-r--r--
Added tag jdk8u141-b12 for changeset 31e8c2a1e8f7
| aoqi@0 | 1 | Nasgen is a tool for processing Java classes that implement native |
| aoqi@0 | 2 | JavaScript objects. It does so by looking for the |
| aoqi@0 | 3 | com.oracle.nashorn.objects.annotations.ScriptClass annotation and other |
| aoqi@0 | 4 | annotations in that package. |
| aoqi@0 | 5 | |
| aoqi@0 | 6 | For each class "C", nasgen instruments the original class and generates |
| aoqi@0 | 7 | two additional classes: a "C$Prototype" class for the JavaScript |
| aoqi@0 | 8 | prototype object, and a "C$Constructor" class for the JavaScript |
| aoqi@0 | 9 | constructor function. |
| aoqi@0 | 10 | |
| aoqi@0 | 11 | Each class instrumented or generated by nasgen contains a private static |
| aoqi@0 | 12 | "$nasgenmap$" field of type com.oracle.nashorn.runtime.PropertyMap and |
| aoqi@0 | 13 | static initializer block to initialize the field to the object's |
| aoqi@0 | 14 | JavaScript properties. |
| aoqi@0 | 15 | |
| aoqi@0 | 16 | Members annotated with @Function, @Property, @Getter, and @Setter are |
| aoqi@0 | 17 | mapped to the $Constructor, $Prototype, or main class, depending on the |
| aoqi@0 | 18 | value of the annotation's 'where' field. By default, @Property, @Getter, |
| aoqi@0 | 19 | and @Setter belong to the main class while @Function methods without |
| aoqi@0 | 20 | explicit 'where' field belong to the $Prototype class. The @Constructor |
| aoqi@0 | 21 | annotation marks a method to be invoked as JavaScript constructor. |
| aoqi@0 | 22 | |
| aoqi@0 | 23 | Nasgen enforces all @Function/@Getter/@Setter/@Constructor annotated |
| aoqi@0 | 24 | methods to be declared as static. Static final @Property fields remain |
| aoqi@0 | 25 | in the main class while other @Property fields are moved to respective |
| aoqi@0 | 26 | classes depending on the annotation's 'where' value. For functions |
| aoqi@0 | 27 | mapped to the $Prototype or $Constructor class, nasgen also generates |
| aoqi@0 | 28 | getters and setters prefixed by G$ and S$, respectively. |
| aoqi@0 | 29 | |
| aoqi@0 | 30 | Nasgen-generated classes are hidden from normal ClassLoaders by giving |
| aoqi@0 | 31 | them a ".clazz" file name extension instead of the standard ".class" |
| aoqi@0 | 32 | extension. This allows script classes to be loaded independently by each |
| aoqi@0 | 33 | Nashorn context through the com.oracle.nashorn.runtime.StructureLoader |
| aoqi@0 | 34 | class loader. |
