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Extended API for Java's Scripting Engine framework
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Extended API for Java's Scripting Engine framework (javax.script) with the Nashorn JavaScript engine.

ScriptController provides:

  • Automatic detection & reloading of script files
  • Global export registry system
  • Builder-style API for constructing new controllers and environments


The main entry point into the API is via ScriptController.

The following is a valid way to obtain an instance.

ScriptController controller = ScriptController.builder().build();

However, it's likely that you'll want to customize certain aspects of the controller.

Logger logger = Logger.getLogger("my-logger");
SpecialObject mySpecialObject = new SpecialObject();

EnvironmentSettings environmentSettings = EnvironmentSettings.builder()
        .withBindings((script, accumulator) -> {
            accumulator.put("specialObject", mySpecialObject);
            accumulator.put("bootstrap", this);

ScriptController controller = ScriptController.builder()

These are just a few examples of the available settings. ScriptController is designed with flexibility in mind.

ScriptControllers "manage" a number of ScriptEnvironments, which center around a root scripts directory.

You can define these environments when building the controller, using .withDirectory(...), or after the controller has been constructed.

ScriptController controller = ScriptController.builder().build();
ScriptEnvironment env = controller.setupNewEnvironment(Paths.get("src"), EnvironmentSettings.defaults());

ScriptEnvironment exposes further instances which make up the overall system.

ExportRegistry exports = env.getExportRegistry();
EnvironmentScriptLoader loader = env.getLoader();
ScriptRegistry scriptRegistry = env.getScriptRegistry();
  • ExportRegistry holds a shared set of "exports". This is effectively a namespace which is shared between scripts.
  • EnvironmentScriptLoader is responsible for loading/reloading/unloading scripts, and monitoring the source directory for changes.
  • ScriptRegistry holds all currently loaded scripts.

The library has extensive JavaDocs - all public classes, methods and fields have documentation. More detailed commentary and explanation on the purpose, behaviour and usage of methods and classes can be found there.

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