Engine

Overview

Module

• package: org.eclipse.dirigible.sdk.platform
• source: platform/Engine.java

Invokes another scripting engine on a file in the registry — most often GraalJS, occasionally Python or another GraalVM polyglot engine. The parameters map is forwarded into the engine's global scope and the engine's natural return value is propagated back.

Useful for hybrid workflows where a Java controller delegates a step to a script in another language (or vice versa) — Dirigible's polyglot runtime lets every language share the same in-process services. For pure in-Java composition prefer regular method calls; spinning up an engine has non-trivial cost compared to invoking a Component bean directly.

Key Features

• Polyglot dispatch: Run a registry-hosted script (JavaScript, TypeScript, Python, …) from Java without an HTTP hop.
• Parameter passing: The supplied Map is exposed in the engine's global scope.
• Debug flag: The full overload supports a debug toggle for breakpoint-friendly execution.
• Engine discovery: listEngines() returns the registered engine type names.

Example Usage

import java.util.Map;
import org.eclipse.dirigible.sdk.platform.Engine;

// Run a registry script in another language with a parameter map:
Object result = Engine.execute(
    "javascript",
    "demo",
    "demo/handlers/hello.ts",
    Map.of("name", "world")
);

// List the registered engine types:
String types = Engine.listEngines();

Methods

execute()

Executes a registry file under the given engine type with an empty parameter map.

public static Object execute(String type, String project, String filePath) throws Exception;

Parameter	Type	Description
type	String	The engine type — e.g. "javascript", "python".
project	String	The project name under /registry/public/.
filePath	String	The path to the script file inside the project.

Returns

• Type: Object
• Description: The engine's natural return value.

execute()

Executes a registry file under the given engine type, passing a parameter map into the engine's global scope.

public static Object execute(String type, String project, String filePath, Map<Object, Object> parameters) throws Exception;

Parameter	Type	Description
type	String	The engine type — e.g. "javascript", "python".
project	String	The project name under /registry/public/.
filePath	String	The path to the script file inside the project.
parameters	Map<Object, Object>	Values to expose in the engine's global scope.

Returns

• Type: Object
• Description: The engine's natural return value.

execute()

Full-form execute with a path parameter, parameter map, and a debug toggle.

public static Object execute(String type, String project, String filePath, String pathParam, Map<Object, Object> parameters, boolean debug)
        throws Exception;

Parameter	Type	Description
type	String	The engine type — e.g. "javascript", "python".
project	String	The project name under /registry/public/.
filePath	String	The path to the script file inside the project.
pathParam	String	An optional path parameter forwarded into the engine.
parameters	Map<Object, Object>	Values to expose in the engine's global scope.
debug	boolean	When true, runs the engine in debug mode (breakpoints honoured).

Returns

• Type: Object
• Description: The engine's natural return value.

listEngines()

Returns the set of registered scripting-engine type names.

public static String listEngines();

Returns

• Type: String
• Description: A serialized list of engine type identifiers (e.g. "javascript", "python").