Package net.neoforged.fml.classloading

Class ModuleClassLoader

java.lang.Object

java.lang.ClassLoader

net.neoforged.fml.classloading.ModuleClassLoader

All Implemented Interfaces:

AutoCloseable

Direct Known Subclasses:

TransformingClassLoader

public class ModuleClassLoader
extends ClassLoader
implements AutoCloseable

This classloader implements child-first classloading for any module that is defined locally.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static final class	ModuleClassLoader.ModuleInfo	Caches the module reader for a module, including its protection domain.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	closed
private final Configuration	configuration
private ClassLoader	fallbackClassLoader
private static final MethodHandle	LAYER_BIND_TO_LOADER
private final Map<String,ModuleClassLoader.ModuleInfo>	moduleInfoCache
private final Map<String,ModuleClassLoader.ModuleInfo>	packageLookup
private final Map<String,ClassLoader>	parentLoaders

Constructor Summary

Constructors

Constructor	Description
ModuleClassLoader(String name, Configuration configuration, List<ModuleLayer> parentLayers)
ModuleClassLoader(String name, Configuration configuration, List<ModuleLayer> parentLayers, @Nullable ClassLoader parentLoader)	This constructor allows setting the parent classloader.

Method Summary

Modifier and Type	Method	Description
private static void	bindToLayer(ModuleClassLoader classLoader, ModuleLayer layer)	Invokes ModuleLayer.bindToLoader(ClassLoader).
void	close()	Closes this classloader and all cached ModuleReader instances.
private Enumeration<URL>	enumerateResources(String name)
protected Class<?>	findClass(String name)
protected Class<?>	findClass(String moduleName, String name)
protected URL	findResource(String moduleName, String name)
protected Enumeration<URL>	findResources(String name)
private static void	forLayerAndParents(ModuleLayer layer, Set<ModuleLayer> visited, Consumer<ModuleLayer> operation)
private static byte[]	getClassBytes(ModuleClassLoader.ModuleInfo moduleInfo, String name)
Configuration	getConfiguration()
protected byte[]	getMaybeTransformedClassBytes(String name, String context)
URL	getResource(String name)
Enumeration<URL>	getResources(String name)
protected Class<?>	loadClass(String name, boolean resolve)
protected byte[]	maybeTransformClassBytes(byte[] bytes, String name, @Nullable String context)
private static @Nullable String	packageName(String className)
private @Nullable Class<?>	readerToClass(ModuleClassLoader.ModuleInfo moduleInfo, String name)	Returns null if the class should be treated as if it doesn't exist.
private URL	readerToURL(ModuleClassLoader.ModuleInfo moduleInfo, String name)
void	setFallbackClassLoader(ClassLoader fallbackClassLoader)
private static Enumeration<URL>	singletonEnumeration(URL url)
private static URL	toURL(Optional<URI> uri)

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findResource, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResourceAsStream, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Field Details

LAYER_BIND_TO_LOADER

private static final MethodHandle LAYER_BIND_TO_LOADER

moduleInfoCache

private final Map<String,ModuleClassLoader.ModuleInfo> moduleInfoCache

packageLookup

private final Map<String,ModuleClassLoader.ModuleInfo> packageLookup

parentLoaders

private final Map<String,ClassLoader> parentLoaders

configuration

private final Configuration configuration

fallbackClassLoader

private ClassLoader fallbackClassLoader

closed

private volatile boolean closed

Constructor Details

ModuleClassLoader

public ModuleClassLoader(String name,
 Configuration configuration,
 List<ModuleLayer> parentLayers)

ModuleClassLoader

public ModuleClassLoader(String name,
 Configuration configuration,
 List<ModuleLayer> parentLayers,
 @Nullable
 @Nullable ClassLoader parentLoader)

This constructor allows setting the parent classloader. Use this with caution since it will allow loading of classes from the classpath directly if the system classloader is reachable from the given parent classloader.

Generally classes that are in packages covered by reachable modules are preferably loaded from these modules. If a class-path entry is not shadowed by a module, specifying a parent class-loader may lead to those classes now being loadable instead of throwing a ClassNotFoundException.

This relaxed classloader isolation is used in unit-testing, where testing libraries are loaded on the system class-loader outside our control (by the Gradle test runner). We must not reload these classes inside the module layers again, otherwise tests throw incompatible exceptions or may not be found at all.

Method Details

bindToLayer

private static void bindToLayer(ModuleClassLoader classLoader,
 ModuleLayer layer)

Invokes ModuleLayer.bindToLoader(ClassLoader).

forLayerAndParents

private static void forLayerAndParents(ModuleLayer layer,
 Set<ModuleLayer> visited,
 Consumer<ModuleLayer> operation)

readerToURL

private URL readerToURL(ModuleClassLoader.ModuleInfo moduleInfo,
 String name)
                 throws IOException

Throws:

IOException

toURL

private static URL toURL(Optional<URI> uri)

getClassBytes

private static byte[] getClassBytes(ModuleClassLoader.ModuleInfo moduleInfo,
 String name)
                             throws IOException

Throws:

IOException

readerToClass

@Nullable
private @Nullable Class<?> readerToClass(ModuleClassLoader.ModuleInfo moduleInfo,
 String name)
                                  throws ClassNotFoundException

Returns null if the class should be treated as if it doesn't exist.

Returns:

null if the class should be treated as if it doesn't exist

Throws:

ClassNotFoundException

maybeTransformClassBytes

protected byte[] maybeTransformClassBytes(byte[] bytes,
 String name,
 @Nullable
 @Nullable String context)

loadClass

protected Class<?> loadClass(String name,
 boolean resolve)
                      throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

getResource

public URL getResource(String name)

Overrides:

getResource in class ClassLoader

findResource

protected URL findResource(String moduleName,
 String name)
                    throws IOException

Overrides:

findResource in class ClassLoader

Throws:

IOException

getResources

public Enumeration<URL> getResources(String name)
                              throws IOException

Overrides:

getResources in class ClassLoader

Throws:

IOException

findResources

protected Enumeration<URL> findResources(String name)
                                  throws IOException

Overrides:

findResources in class ClassLoader

Throws:

IOException

enumerateResources

private Enumeration<URL> enumerateResources(String name)
                                     throws IOException

Throws:

IOException

singletonEnumeration

private static Enumeration<URL> singletonEnumeration(URL url)

findClass

protected Class<?> findClass(String moduleName,
 String name)

Overrides:

findClass in class ClassLoader

findClass

protected Class<?> findClass(String name)
                      throws ClassNotFoundException

Overrides:

findClass in class ClassLoader

Throws:

ClassNotFoundException

getMaybeTransformedClassBytes

protected byte[] getMaybeTransformedClassBytes(String name,
 String context)
                                        throws ClassNotFoundException

Throws:

ClassNotFoundException

setFallbackClassLoader

public void setFallbackClassLoader(ClassLoader fallbackClassLoader)

close

public void close()
           throws IOException

Closes this classloader and all cached ModuleReader instances. This method is thread-safe and idempotent.

Specified by:

close in interface AutoCloseable

Throws:

IOException - if an I/O error occurs while closing module readers

packageName

@Nullable
private static @Nullable String packageName(String className)

getConfiguration

public Configuration getConfiguration()