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