Package org.jboss.modules

Class ModuleClassLoader

java.lang.Object

java.lang.ClassLoader

org.jboss.modules.NamedClassLoader

org.jboss.modules.ConcurrentClassLoader

org.jboss.modules.ModuleClassLoader

public class ModuleClassLoader
extends ConcurrentClassLoader

A module classloader. Instances of this class implement the complete view of classes and resources available in a module. Contrast with Module, which has API methods to access the exported view of classes and resources.

Author:

John Bailey, David M. Lloyd, thomas.diesler@jboss.com

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ModuleClassLoader.Configuration	An opaque configuration used internally to create a module class loader.

Field Summary

Fields inherited from class org.jboss.modules.ConcurrentClassLoader

EMPTY_ENUMERATION

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ModuleClassLoader(ModuleClassLoader.Configuration configuration)	Construct a new instance.

Method Summary

Modifier and Type	Method	Description
void	clearAssertionStatus()
protected java.lang.Object	clone()
protected java.lang.Package	definePackage(java.lang.String name, java.lang.String specTitle, java.lang.String specVersion, java.lang.String specVendor, java.lang.String implTitle, java.lang.String implVersion, java.lang.String implVendor, java.net.URL sealBase)	Defines a package by name in this ConcurrentClassLoader.
boolean	equals(java.lang.Object obj)
protected void	finalize()
protected java.lang.Class<?>	findClass(java.lang.String className, boolean exportsOnly, boolean resolve)	Find a class, possibly delegating to other loader(s).
protected java.lang.String	findLibrary(java.lang.String libname)	Find a library from one of the resource loaders.
java.net.URL	findResource(java.lang.String name, boolean exportsOnly)	Find the resource with the given name and exported status.
java.io.InputStream	findResourceAsStream(java.lang.String name, boolean exportsOnly)	Finds the resource with the given name and exported status, returning the resource content as a stream.
java.util.Enumeration<java.net.URL>	findResources(java.lang.String name, boolean exportsOnly)	Finds the resources with the given name and exported status.
protected java.lang.String	getClassNotFoundExceptionMessage(java.lang.String className, Module fromModule)	Returns an exception message used when producing instances of ClassNotFoundException.
java.util.Set<java.lang.String>	getLocalPaths()	Get the (unmodifiable) set of paths which are locally available in this module class loader.
Module	getModule()	Get the module for this class loader.
java.lang.String	getName()	Get the name of this module.
protected java.lang.Package	getPackageByName(java.lang.String name)	Perform the actual work to load a package which is visible to this class loader.
protected java.lang.Package[]	getPackages()	Get all defined packages which are visible to this class loader.
int	hashCode()
java.util.Iterator<Resource>	iterateResources(java.lang.String startName, boolean recurse)	Iterate the resources within this module class loader.
java.lang.Class<?>	loadClassLocal(java.lang.String className)	Load a class from this class loader.
java.lang.Class<?>	loadClassLocal(java.lang.String className, boolean resolve)	Load a local class from this class loader.
java.util.List<Resource>	loadResourceLocal(java.lang.String name)	Load a local exported resource from this class loader.
protected void	postDefine(ClassSpec classSpec, java.lang.Class<?> definedClass)	A hook which is invoked after a class is defined.
protected void	preDefine(ClassSpec classSpec, java.lang.String className)	A hook which is invoked before a class is defined.
void	setClassAssertionStatus(java.lang.String className, boolean enabled)
void	setDefaultAssertionStatus(boolean enabled)
void	setPackageAssertionStatus(java.lang.String packageName, boolean enabled)
java.lang.String	toString()	Get a string representation of this class loader.

Methods inherited from class java.lang.ClassLoader

defineClass, defineClass, defineClass, defineClass, findLoadedClass, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getParent, getPlatformClassLoader, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, registerAsParallelCapable, resolveClass, resources, setSigners

Methods inherited from class org.jboss.modules.ConcurrentClassLoader

defineOrLoadClass, defineOrLoadClass, findClass, findClass, findLoadedPackage, findResource, findResource, findResources, getPackage, getResource, getResourceAsStream, getResources, loadClass, loadClass, loadExportedClass, loadExportedClass

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ModuleClassLoader

protected ModuleClassLoader(ModuleClassLoader.Configuration configuration)

Construct a new instance.

Parameters:

configuration - the module class loader configuration to use

Method Detail

findClass

protected final java.lang.Class<?> findClass(java.lang.String className,
                                             boolean exportsOnly,
                                             boolean resolve)
                                      throws java.lang.ClassNotFoundException

Find a class, possibly delegating to other loader(s). This method should never synchronize across a delegation method call of any sort. The default implementation always throws ClassNotFoundException.

If a class is to be defined by this method, it should be done via one of the atomic defineOrLoadClass methods rather than defineClass() in order to avoid spurious exceptions.

Overrides:

findClass in class ConcurrentClassLoader

Parameters:

className - the class name

exportsOnly - true if only exported classes should be considered

resolve - true if the class should be linked after loading

Returns:

the class

Throws:

java.lang.ClassNotFoundException - if the class is not found

getClassNotFoundExceptionMessage

protected java.lang.String getClassNotFoundExceptionMessage(java.lang.String className,
                                                            Module fromModule)

Returns an exception message used when producing instances of ClassNotFoundException. This can be overridden by subclasses to customise the error message.

Parameters:

className - the name of the class which is missing

fromModule - the module from which the class could not be found

Returns:

an exception message used when producing instances of ClassNotFoundException

loadClassLocal

public java.lang.Class<?> loadClassLocal(java.lang.String className)
                                  throws java.lang.ClassNotFoundException

Load a class from this class loader.

Parameters:

className - the class name to load

Returns:

the loaded class or null if it was not found

Throws:

java.lang.ClassNotFoundException - if an exception occurs while loading the class or its dependencies

loadClassLocal

public java.lang.Class<?> loadClassLocal(java.lang.String className,
                                         boolean resolve)
                                  throws java.lang.ClassNotFoundException

Load a local class from this class loader.

Parameters:

className - the class name

resolve - true to resolve the loaded class

Returns:

the loaded class or null if it was not found

Throws:

java.lang.ClassNotFoundException - if an error occurs while loading the class

loadResourceLocal

public java.util.List<Resource> loadResourceLocal(java.lang.String name)

Load a local exported resource from this class loader.

Parameters:

name - the resource name

Returns:

the list of resources

preDefine

protected void preDefine(ClassSpec classSpec,
                         java.lang.String className)

A hook which is invoked before a class is defined.

Parameters:

classSpec - the class spec of the defined class

className - the class to be defined

postDefine

protected void postDefine(ClassSpec classSpec,
                          java.lang.Class<?> definedClass)

A hook which is invoked after a class is defined.

Parameters:

classSpec - the class spec of the defined class

definedClass - the class that was defined

findLibrary

protected final java.lang.String findLibrary(java.lang.String libname)

Find a library from one of the resource loaders.

Overrides:

findLibrary in class java.lang.ClassLoader

Parameters:

libname - the library name

Returns:

the full absolute path to the library

findResource

public final java.net.URL findResource(java.lang.String name,
                                       boolean exportsOnly)

Find the resource with the given name and exported status.

Overrides:

findResource in class ConcurrentClassLoader

Parameters:

name - the resource name

exportsOnly - true to consider only exported resources or false to consider all resources

Returns:

the resource URL

See Also:

ConcurrentClassLoader.getResource(String)

findResources

public final java.util.Enumeration<java.net.URL> findResources(java.lang.String name,
                                                               boolean exportsOnly)

Finds the resources with the given name and exported status.

Overrides:

findResources in class ConcurrentClassLoader

Parameters:

name - the resource name

exportsOnly - true to consider only exported resources or false to consider all resources

Returns:

the resource enumeration

See Also:

ConcurrentClassLoader.getResources(String)

findResourceAsStream

public final java.io.InputStream findResourceAsStream(java.lang.String name,
                                                      boolean exportsOnly)

Finds the resource with the given name and exported status, returning the resource content as a stream.

Overrides:

findResourceAsStream in class ConcurrentClassLoader

Parameters:

name - the resource name

exportsOnly - true to consider only exported resources or false to consider all resources

Returns:

the resource stream, or null if the resource is not found

getModule

public final Module getModule()

Get the module for this class loader.

Returns:

the module

getName

public final java.lang.String getName()

Get the name of this module. This method is used by Java 9 in debug output.

Overrides:

getName in class NamedClassLoader

Returns:

the name of this module

toString

public final java.lang.String toString()

Get a string representation of this class loader.

Overrides:

toString in class java.lang.Object

Returns:

the string

definePackage

protected final java.lang.Package definePackage(java.lang.String name,
                                                java.lang.String specTitle,
                                                java.lang.String specVersion,
                                                java.lang.String specVendor,
                                                java.lang.String implTitle,
                                                java.lang.String implVersion,
                                                java.lang.String implVendor,
                                                java.net.URL sealBase)
                                         throws java.lang.IllegalArgumentException

Defines a package by name in this ConcurrentClassLoader. If the package was already defined, the existing package is returned instead.

Overrides:

definePackage in class ConcurrentClassLoader

Parameters:

name - the package name

specTitle - the specification title

specVersion - the specification version

specVendor - the specification vendor

implTitle - the implementation title

implVersion - the implementation version

implVendor - the implementation vendor

sealBase - if not null, then this package is sealed with respect to the given code source URL

Returns:

the newly defined package, or the existing one if one was already defined

Throws:

java.lang.IllegalArgumentException

getPackageByName

protected final java.lang.Package getPackageByName(java.lang.String name)

Perform the actual work to load a package which is visible to this class loader. By default, uses a simple parent-first delegation strategy.

Overrides:

getPackageByName in class ConcurrentClassLoader

Parameters:

name - the package name

Returns:

the package, or null if no such package is visible to this class loader

getPackages

protected final java.lang.Package[] getPackages()

Get all defined packages which are visible to this class loader.

Overrides:

getPackages in class ConcurrentClassLoader

Returns:

the packages

setDefaultAssertionStatus

public final void setDefaultAssertionStatus(boolean enabled)

Overrides:

setDefaultAssertionStatus in class java.lang.ClassLoader

setPackageAssertionStatus

public final void setPackageAssertionStatus(java.lang.String packageName,
                                            boolean enabled)

Overrides:

setPackageAssertionStatus in class java.lang.ClassLoader

setClassAssertionStatus

public final void setClassAssertionStatus(java.lang.String className,
                                          boolean enabled)

Overrides:

setClassAssertionStatus in class java.lang.ClassLoader

clearAssertionStatus

public final void clearAssertionStatus()

Overrides:

clearAssertionStatus in class java.lang.ClassLoader

hashCode

public final int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public final boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

clone

protected final java.lang.Object clone()
                                throws java.lang.CloneNotSupportedException

Overrides:

clone in class java.lang.Object

Throws:

java.lang.CloneNotSupportedException

finalize

protected final void finalize()
                       throws java.lang.Throwable

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

iterateResources

public final java.util.Iterator<Resource> iterateResources(java.lang.String startName,
                                                           boolean recurse)

Iterate the resources within this module class loader. Only resource roots which are inherently iterable will be checked, thus the result of this method may only be a subset of the actual loadable resources. The returned resources are not sorted or grouped in any particular way.

Parameters:

startName - the directory name to search

recurse - true to recurse into subdirectories, false otherwise

Returns:

the resource iterator

getLocalPaths

public final java.util.Set<java.lang.String> getLocalPaths()

Get the (unmodifiable) set of paths which are locally available in this module class loader. The set will include all paths defined by the module's resource loaders, minus any paths excluded by filters. The set will generally always contain an empty entry (""). The set is unordered and unsorted, and is iterable in O(n) time and accessible in O(1) time.

Returns:

the set of local paths