org.eclipse.scada.utils.script

Class Scripts

java.lang.Object

org.eclipse.scada.utils.script.Scripts

public final class Scripts
extends Object

Helper functions for JSR 223 scripts

This is mostly about class loaders. Scripts have at least three class loaders to worry about. The first is the thread context class loader. The second is the class loader used by ScriptEngineManager to find the implementations of script languages. The third is the class loaders used by the script engine to find additional classes.

For Rhino this is all pretty straight forward. The class loaders used by the script is the current thread context class loader. However this was changed with Nashorn. Here the script has a special class loader, used inside the script. This can be set using a non-standard API, however the default value for this class loader is the current thread context class loader during creation of the ScriptEngine instance.

Method Summary

Modifier and Type	Method and Description
static ScriptEngine	createEngine(ScriptEngineManager engineManager, String engineName, ClassLoader scriptClassLoader)
static ScriptEngine	createEngine(String engineName, ClassLoader scriptClassLoader)
static ScriptEngineManager	createManager(ClassLoader contextClassLoader) Create a new script engine manager
static <V> V	executeWithClassLoader(ClassLoader classLoader, Callable<V> callable)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

createManager

public static ScriptEngineManager createManager(ClassLoader contextClassLoader)

Create a new script engine manager

Note: The context class loader will be set during the creation of the script engine. However the constructor ScriptEngineManager.ScriptEngineManager(ClassLoader) with the parameter null will still be used in order to look up the default script languages of the JRE.

Parameters:

contextClassLoader - the context class loader to use

Returns:

a new instanceof a ScriptEngineManager

createEngine

public static ScriptEngine createEngine(String engineName,
                                        ClassLoader scriptClassLoader)
                                 throws Exception

Throws:

Exception

createEngine

public static ScriptEngine createEngine(ScriptEngineManager engineManager,
                                        String engineName,
                                        ClassLoader scriptClassLoader)
                                 throws Exception

Throws:

Exception

executeWithClassLoader

public static <V> V executeWithClassLoader(ClassLoader classLoader,
                                           Callable<V> callable)
                                    throws Exception

Throws:

Exception