org.luaj.vm2.server
Class LuajClassLoader

java.lang.Object
  java.lang.ClassLoader
      org.luaj.vm2.server.LuajClassLoader

public class LuajClassLoader
extends java.lang.ClassLoader

Class loader that can be used to launch a lua script in a Java VM that has a unique set of classes for org.luaj classes.

Note: This class is experimental and subject to change in future versions.

By using a custom class loader per script, it allows the script to have its own set of globals, including static values such as shared metatables that cannot access lua values from other scripts because their classes are loaded from different class loaders. Thus normally unsafe libraries such as luajava can be exposed to scripts in a server environment using these techniques.

All classes in the package "org.luaj.vm2." are considered user classes, and loaded into this class loader from their bytes in the class path. Other classes are considered systemc classes and loaded via the system loader. This class set can be extended by overriding isUserClass(String).

The Launcher interface is loaded as a system class by exception so that the caller may use it to launch lua scripts.

By default NewLauncher() creates a subclass of Launcher of type DefaultLauncher which creates debug globals, runs the script, and prints the return values. This behavior can be changed by supplying a different implementation class to NewLauncher(Class) which must extend Launcher.

Since:

luaj 3.0.1

See Also:

Launcher, NewLauncher(), NewLauncher(Class), DefaultLauncher

Constructor Summary

LuajClassLoader()

Method Summary

static boolean	isUserClass(java.lang.String classname) Test if a class name should be considered a user class and loaded by this loader, or a system class and loaded by the system loader.
java.lang.Class<?>	loadClass(java.lang.String classname)
static Launcher	NewLauncher() Construct a default Launcher instance that will load classes in its own LuajClassLoader using the default implementation class DefaultLauncher.
static Launcher	NewLauncher(java.lang.Class<? extends Launcher> launcher_class) Construct a Launcher instance that will load classes in its own LuajClassLoader using a user-supplied implementation class that implements Launcher.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResource, findResources, findSystemClass, getPackage, getPackages, getParent, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

LuajClassLoader

public LuajClassLoader()

Method Detail

NewLauncher

public static Launcher NewLauncher()
                            throws java.lang.InstantiationException,
                                   java.lang.IllegalAccessException,
                                   java.lang.ClassNotFoundException

Construct a default Launcher instance that will load classes in its own LuajClassLoader using the default implementation class DefaultLauncher.

The Launcher that is returned will be a pristine luaj vm whose classes are loaded into this loader including static variables such as shared metatables, and should not be able to directly access variables from other Launcher instances.

Returns:

Launcher instance that can be used to launch scripts.

Throws:

java.lang.InstantiationException

java.lang.IllegalAccessException

java.lang.ClassNotFoundException

NewLauncher

public static Launcher NewLauncher(java.lang.Class<? extends Launcher> launcher_class)
                            throws java.lang.InstantiationException,
                                   java.lang.IllegalAccessException,
                                   java.lang.ClassNotFoundException

Construct a Launcher instance that will load classes in its own LuajClassLoader using a user-supplied implementation class that implements Launcher.

The Launcher that is returned will be a pristine luaj vm whose classes are loaded into this loader including static variables such as shared metatables, and should not be able to directly access variables from other Launcher instances.

Returns:

instance of type 'launcher_class' that can be used to launch scripts.

Throws:

java.lang.InstantiationException

java.lang.IllegalAccessException

java.lang.ClassNotFoundException

isUserClass

public static boolean isUserClass(java.lang.String classname)

Test if a class name should be considered a user class and loaded by this loader, or a system class and loaded by the system loader.

Parameters:

classname - Class name to test.

Returns:

true if this should be loaded into this class loader.

loadClass

public java.lang.Class<?> loadClass(java.lang.String classname)
                             throws java.lang.ClassNotFoundException

Overrides:

loadClass in class java.lang.ClassLoader

Throws:

java.lang.ClassNotFoundException