ch.grengine.engine

Class LayeredEngine

java.lang.Object

ch.grengine.engine.LayeredEngine

All Implemented Interfaces:

Engine, Closeable, AutoCloseable

public class LayeredEngine
extends Object
implements Engine

Engine based on instances of LayeredClassLoader.

Since:

1.0

Author:

Alain Stalder, Made in Switzerland.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LayeredEngine.Builder Builder for instances of LayeredEngine.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	LayeredEngine(LayeredEngine.Builder builder) constructor from builder.

Method Summary

Modifier and Type	Method and Description
ClassLoader	asClassLoader(Loader loader) returns a class loader based on this engine and the given loader.
void	close() release metadata for all classed ever loaded using this engine.
LayeredEngine.Builder	getBuilder() gets the builder.
Loader	getLoader() gets the default attached loader.
Class<?>	loadClass(Loader loader, Source source, String name) loads a class with the given name and from the given source from the given loader.
Class<?>	loadClass(Loader loader, String name) loads a class by name from the given loader.
Class<?>	loadMainClass(Loader loader, Source source) loads the main class of the given source from the given loader.
Loader	newAttachedLoader() creates and gets a new attached loader, backed by the same bytecode as all other shared loaders created by this engine, with a top code cache shared with all other attached loaders of this engine and automatically updated if code layers are set.
Loader	newDetachedLoader() creates and gets a new detached loader, backed initially by the same bytecode as all attached loaders created by this engine (code layers and top code cache), but not updated if code layers are set and with a separate top code cache instance.
void	setCodeLayers(List<Code> codeLayers) sets (replaces) code layers of the engine, based on already compiled code layers.
void	setCodeLayersBySource(List<Sources> sourcesLayers) sets (replaces) code layers of the engine, based on sources to compile to code layers.

Methods inherited from class java.lang.Object

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

Constructor Detail

LayeredEngine

protected LayeredEngine(LayeredEngine.Builder builder)

constructor from builder.

Parameters:

builder - builder

Since:

1.0

Method Detail

getLoader

public Loader getLoader()

Description copied from interface: Engine

gets the default attached loader.

Specified by:

getLoader in interface Engine

Returns:

default attached loader

newAttachedLoader

public Loader newAttachedLoader()

creates and gets a new attached loader, backed by the same bytecode as all other shared loaders created by this engine, with a top code cache shared with all other attached loaders of this engine and automatically updated if code layers are set.

Specified by:

newAttachedLoader in interface Engine

Returns:

new attached loader

Since:

1.0

newDetachedLoader

public Loader newDetachedLoader()

creates and gets a new detached loader, backed initially by the same bytecode as all attached loaders created by this engine (code layers and top code cache), but not updated if code layers are set and with a separate top code cache instance.

For example, a web application might create a detached loader for each new HTTP session: A new loader in order to separate static variables of scripts between sessions (security feature); a detached loader in order to keep code layers constant during the lifetime of the session (consistent behavior of Groovy script calls).

Specified by:

newDetachedLoader in interface Engine

Returns:

new detached loader

Since:

1.0

loadMainClass

public Class<?> loadMainClass(Loader loader,
                              Source source)

Description copied from interface: Engine

loads the main class of the given source from the given loader.

Note that if a class with the main class name is available for loading, but was not compiled as part of a set of Source that included the given source, that class will not count for loading.

Specified by:

loadMainClass in interface Engine

Parameters:

loader - loader

source - source

Returns:

loaded class

loadClass

public Class<?> loadClass(Loader loader,
                          Source source,
                          String name)

Description copied from interface: Engine

loads a class with the given name and from the given source from the given loader.

Note that if a class with the given class name is available for loading, but was not compiled as part of a set of Source that included the given source, that class will not count for loading.

Specified by:

loadClass in interface Engine

Parameters:

loader - loader

source - source

name - class name

Returns:

loaded class

loadClass

public Class<?> loadClass(Loader loader,
                          String name)

Description copied from interface: Engine

loads a class by name from the given loader.

Note that a top code cache is not searched in this case, because each set of source has its own top loader.

Specified by:

loadClass in interface Engine

Parameters:

loader - loader

name - class name

Returns:

loaded class

setCodeLayers

public void setCodeLayers(List<Code> codeLayers)

Description copied from interface: Engine

sets (replaces) code layers of the engine, based on already compiled code layers.

Note that normally it is supported to do this "live", while the engine is used.

Specified by:

setCodeLayers in interface Engine

Parameters:

codeLayers - code layers

setCodeLayersBySource

public void setCodeLayersBySource(List<Sources> sourcesLayers)

Description copied from interface: Engine

sets (replaces) code layers of the engine, based on sources to compile to code layers.

Note that normally it is supported to do this "live", while the engine is used.

Specified by:

setCodeLayersBySource in interface Engine

Parameters:

sourcesLayers - sources layers

close

public void close()

Description copied from interface: Engine

release metadata for all classed ever loaded using this engine.

Allows to remove metadata associated by Groovy (or Java) with a class, which is often necessary to get on-the-fly garbage collection.

Generally call only when really done using this engine and all loaded classes; subsequently trying to use this engine or its classes results generally in undefined behavior.

Specified by:

close in interface Engine

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

asClassLoader

public ClassLoader asClassLoader(Loader loader)

Description copied from interface: Engine

returns a class loader based on this engine and the given loader.

Note that the returned class loader typically does not load classes itself; it just wraps the engine and its loader.

Specified by:

asClassLoader in interface Engine

Parameters:

loader - loader

Returns:

class loader

getBuilder

public LayeredEngine.Builder getBuilder()

gets the builder.

Returns:

builder

Since:

1.0