org.eclipse.osgi.internal.hookregistry

Class ClassLoaderHook

java.lang.Object

org.eclipse.osgi.internal.hookregistry.ClassLoaderHook

Direct Known Subclasses:

DevClassLoadingHook, EclipseLazyStarter, WeavingHookConfigurator

public abstract class ClassLoaderHook
extends Object

A class loading hook that hooks into a module class loader

Constructor Summary

Constructors

Constructor and Description
ClassLoaderHook()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addClassPathEntry(ArrayList<ClasspathEntry> cpEntries, String cp, ClasspathManager hostmanager, BundleInfo.Generation sourceGeneration) Gets called by a classpath manager when looking for ClasspathEntry objects.
void	classLoaderCreated(ModuleClassLoader classLoader) Gets called by a classpath manager at the end of BundleLoader.getClassLoader() is called the first time and a class loader is created.
ModuleClassLoader	createClassLoader(ClassLoader parent, EquinoxConfiguration configuration, BundleLoader delegate, BundleInfo.Generation generation) Gets called by a bundle loader when BundleLoader.getClassLoader() is called the first time in order to allow a hook to create the class loader.
String	findLocalLibrary(BundleInfo.Generation generation, String libName) Gets called by a base data during ModuleClassLoader.findLibrary(String).
ClassLoader	getModuleClassLoaderParent(EquinoxConfiguration configuration) Returns the parent class loader to be used by all ModuleClassLoaders.
Class<?>	postFindClass(String name, ModuleClassLoader classLoader) Called by a BundleLoader.findClass(String) method after delegating to the resolved constraints and local bundle for a class load.
String	postFindLibrary(String name, ModuleClassLoader classLoader) Called by a ClasspathManager after normal delegation.
void	postFindLocalClass(String name, Class<?> clazz, ClasspathManager manager) Gets called by a classpath manager during ClasspathManager.findLocalClass(String) after searching the local classloader for a class.
void	postFindLocalResource(String name, URL resource, ClasspathManager manager) Gets called by a classpath manager during ClasspathManager.findLocalResource(String) after searching the local classloader for a resource.
URL	postFindResource(String name, ModuleClassLoader classLoader) Called by a BundleLoader.findResource(String) after delegating to the resolved constraints and local bundle for a resource load.
Enumeration<URL>	postFindResources(String name, ModuleClassLoader classLoader) Called by a BundleLoader.findResources(String) after delegating to the resolved constraints and local bundle for a resource load.
Class<?>	preFindClass(String name, ModuleClassLoader classLoader) Called by a BundleLoader.findClass(String) method before delegating to the resolved constraints and local bundle for a class load.
String	preFindLibrary(String name, ModuleClassLoader classLoader) Called by a ClasspathManager before normal delegation.
void	preFindLocalClass(String name, ClasspathManager manager) Gets called by a classpath manager during ClasspathManager.findLocalClass(String) before searching the local classloader for a class.
void	preFindLocalResource(String name, ClasspathManager manager) Gets called by a classpath manager during ClasspathManager.findLocalResource(String) before searching the local classloader for a resource.
URL	preFindResource(String name, ModuleClassLoader classLoader) Called by a BundleLoader.findResource(String) before delegating to the resolved constraints and local bundle for a resource load.
Enumeration<URL>	preFindResources(String name, ModuleClassLoader classLoader) Called by a BundleLoader.findResources(String) before delegating to the resolved constraints and local bundle for a resource load.
byte[]	processClass(String name, byte[] classbytes, ClasspathEntry classpathEntry, BundleEntry entry, ClasspathManager manager) Gets called by a classpath manager before defining a class.
void	recordClassDefine(String name, Class<?> clazz, byte[] classbytes, ClasspathEntry classpathEntry, BundleEntry entry, ClasspathManager manager) Gets called by a classpath manager after an attempt is made to define a class.
boolean	rejectTransformation(String name, byte[] transformedBytes, ClasspathEntry classpathEntry, BundleEntry entry, ClasspathManager manager) Gets called by a classpath manager before defining a class.

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassLoaderHook

public ClassLoaderHook()

Method Detail

processClass

public byte[] processClass(String name,
                  byte[] classbytes,
                  ClasspathEntry classpathEntry,
                  BundleEntry entry,
                  ClasspathManager manager)

Gets called by a classpath manager before defining a class. This method allows a class loading hook to process the bytes of a class that is about to be defined and return a transformed byte array.

Parameters:

name - the name of the class being defined

classbytes - the bytes of the class being defined

classpathEntry - the ClasspathEntry where the class bytes have been read from.

entry - the BundleEntry source of the class bytes

manager - the class path manager used to define the requested class

Returns:

a transformed array of classbytes or null if the original bytes should be used.

rejectTransformation

public boolean rejectTransformation(String name,
                           byte[] transformedBytes,
                           ClasspathEntry classpathEntry,
                           BundleEntry entry,
                           ClasspathManager manager)

Gets called by a classpath manager before defining a class. This method allows a class loading hook to reject a transformation to the class bytes by a processClass method.

Parameters:

name - the name of the class being defined

transformedBytes - the transformed bytes of the class being defined

classpathEntry - the ClasspathEntry where the class bytes have been read from

entry - the BundleEntry source of the class bytes

manager - the class path manager used to define the requested class

Returns:

returns true if the modified bytes should be rejected; otherwise false is returned

addClassPathEntry

public boolean addClassPathEntry(ArrayList<ClasspathEntry> cpEntries,
                        String cp,
                        ClasspathManager hostmanager,
                        BundleInfo.Generation sourceGeneration)

Gets called by a classpath manager when looking for ClasspathEntry objects. This method allows a classloading hook to add additional ClasspathEntry objects

Parameters:

cpEntries - the list of ClasspathEntry objects currently available for the requested classpath

cp - the name of the requested classpath

hostmanager - the classpath manager the requested ClasspathEntry is for

sourceGeneration - the source generation of the requested ClasspathEntry

Returns:

true if a ClasspathEntry has been added to cpEntries

findLocalLibrary

public String findLocalLibrary(BundleInfo.Generation generation,
                      String libName)

Gets called by a base data during ModuleClassLoader.findLibrary(String). A this method is called for each configured class loading hook until one class loading hook returns a non-null value. If no class loading hook returns a non-null value then the default behavior will be used.

Parameters:

generation - the bundle generation to find a native library for.

libName - the name of the native library.

Returns:

The absolute path name of the native library or null.

createClassLoader

public ModuleClassLoader createClassLoader(ClassLoader parent,
                                  EquinoxConfiguration configuration,
                                  BundleLoader delegate,
                                  BundleInfo.Generation generation)

Gets called by a bundle loader when BundleLoader.getClassLoader() is called the first time in order to allow a hook to create the class loader. This should rarely, if ever be overridden. The default implementation returns null indicating the built-in implementation should be used. Only one hook is able to provide the implementation of the module class loader and the first one to return non-null wins.

Parameters:

parent - the parent classloader

configuration - the equinox configuration

delegate - the delegate for this classloader

generation - the generation for this class loader

Returns:

returns an implementation of a module class loader or null if the built-in implemention is to be used.

classLoaderCreated

public void classLoaderCreated(ModuleClassLoader classLoader)

Gets called by a classpath manager at the end of BundleLoader.getClassLoader() is called the first time and a class loader is created.

Parameters:

classLoader - the newly created bundle classloader

preFindClass

public Class<?> preFindClass(String name,
                    ModuleClassLoader classLoader)
                      throws ClassNotFoundException

Called by a BundleLoader.findClass(String) method before delegating to the resolved constraints and local bundle for a class load. If this method returns null then normal delegation is done. If this method returns a non-null value then the rest of the delegation process is skipped and the returned value is used. If this method throws a ClassNotFoundException then the calling BundleLoader.findClass(String) method re-throws the exception.

Parameters:

name - the name of the class to find

classLoader - the module class loader

Returns:

the class found by this hook or null if normal delegation should continue

Throws:

ClassNotFoundException - to terminate the delegation and throw an exception

postFindClass

public Class<?> postFindClass(String name,
                     ModuleClassLoader classLoader)
                       throws ClassNotFoundException

Called by a BundleLoader.findClass(String) method after delegating to the resolved constraints and local bundle for a class load. This method will only be called if no class was found from the normal delegation.

Parameters:

name - the name of the class to find

classLoader - the bundle class loader

Returns:

the class found by this hook or null if normal delegation should continue

Throws:

ClassNotFoundException - to terminate the delegation and throw an exception

preFindResource

public URL preFindResource(String name,
                  ModuleClassLoader classLoader)
                    throws FileNotFoundException

Called by a BundleLoader.findResource(String) before delegating to the resolved constraints and local bundle for a resource load. If this method returns null then normal delegation is done. If this method returns a non-null value then the rest of the delegation process is skipped and the returned value is used. If this method throws an FileNotFoundException then the delegation is terminated.

Parameters:

name - the name of the resource to find

classLoader - the bundle class loader

Returns:

the resource found by this hook or null if normal delegation should continue

Throws:

FileNotFoundException - to terminate the delegation

postFindResource

public URL postFindResource(String name,
                   ModuleClassLoader classLoader)
                     throws FileNotFoundException

Called by a BundleLoader.findResource(String) after delegating to the resolved constraints and local bundle for a resource load. This method will only be called if no resource was found from the normal delegation.

Parameters:

name - the name of the resource to find

classLoader - the bundle class loader

Returns:

the resource found by this hook or null if normal delegation should continue

Throws:

FileNotFoundException - to terminate the delegation

preFindResources

public Enumeration<URL> preFindResources(String name,
                                ModuleClassLoader classLoader)
                                  throws FileNotFoundException

Called by a BundleLoader.findResources(String) before delegating to the resolved constraints and local bundle for a resource load. If this method returns null then normal delegation is done. If this method returns a non-null value then the rest of the delegation process is skipped and the returned value is used. If this method throws an FileNotFoundException then the delegation is terminated

Parameters:

name - the name of the resource to find

classLoader - the bundle class loader

Returns:

the resources found by this hook or null if normal delegation should continue

Throws:

FileNotFoundException - to terminate the delegation

postFindResources

public Enumeration<URL> postFindResources(String name,
                                 ModuleClassLoader classLoader)
                                   throws FileNotFoundException

Called by a BundleLoader.findResources(String) after delegating to the resolved constraints and local bundle for a resource load. This method will only be called if no resources were found from the normal delegation.

Parameters:

name - the name of the resource to find

classLoader - the bundle class loader

Returns:

the resources found by this hook or null if normal delegation should continue

Throws:

FileNotFoundException - to terminate the delegation

preFindLibrary

public String preFindLibrary(String name,
                    ModuleClassLoader classLoader)
                      throws FileNotFoundException

Called by a ClasspathManager before normal delegation. If this method returns a non-null value then the rest of the delegation process is skipped and the returned value is used.

Parameters:

name - the name of the library to find

classLoader - the bundle class loader

Returns:

the library found by this hook or null if normal delegation should continue

Throws:

FileNotFoundException - to terminate the delegation

postFindLibrary

public String postFindLibrary(String name,
                     ModuleClassLoader classLoader)

Called by a ClasspathManager after normal delegation. This method will only be called if no library was found from the normal delegation.

Parameters:

name - the name of the library to find

classLoader - the bundle class loader

Returns:

the library found by this hook or null if normal delegation should continue

preFindLocalClass

public void preFindLocalClass(String name,
                     ClasspathManager manager)
                       throws ClassNotFoundException

Gets called by a classpath manager during ClasspathManager.findLocalClass(String) before searching the local classloader for a class. A classpath manager will call this method for each configured class loading stat hook.

Parameters:

name - the name of the requested class

manager - the classpath manager used to find and load the requested class

Throws:

ClassNotFoundException - to prevent the requested class from loading

postFindLocalClass

public void postFindLocalClass(String name,
                      Class<?> clazz,
                      ClasspathManager manager)
                        throws ClassNotFoundException

Gets called by a classpath manager during ClasspathManager.findLocalClass(String) after searching the local classloader for a class. A classpath manager will call this method for each configured class loading stat hook.

Parameters:

name - the name of the requested class

clazz - the loaded class or null if not found

manager - the classpath manager used to find and load the requested class

Throws:

ClassNotFoundException

preFindLocalResource

public void preFindLocalResource(String name,
                        ClasspathManager manager)

Gets called by a classpath manager during ClasspathManager.findLocalResource(String) before searching the local classloader for a resource. A classpath manager will call this method for each configured class loading stat hook.

Parameters:

name - the name of the requested resource

manager - the classpath manager used to find the requested resource

postFindLocalResource

public void postFindLocalResource(String name,
                         URL resource,
                         ClasspathManager manager)

Gets called by a classpath manager during ClasspathManager.findLocalResource(String) after searching the local classloader for a resource. A classpath manager will call this method for each configured class loading stat hook.

Parameters:

name - the name of the requested resource

resource - the URL to the requested resource or null if not found

manager - the classpath manager used to find the requested resource

recordClassDefine

public void recordClassDefine(String name,
                     Class<?> clazz,
                     byte[] classbytes,
                     ClasspathEntry classpathEntry,
                     BundleEntry entry,
                     ClasspathManager manager)

Gets called by a classpath manager after an attempt is made to define a class. This method allows a class loading stat hook to record data about a class definition.

Parameters:

name - the name of the class that got defined

clazz - the class object that got defined or null if an error occurred while defining a class

classbytes - the class bytes used to define the class

classpathEntry - the ClasspathEntry where the class bytes got read from

entry - the BundleEntyr source of the class bytes

manager - the classpath manager used to define the class

getModuleClassLoaderParent

public ClassLoader getModuleClassLoaderParent(EquinoxConfiguration configuration)

Returns the parent class loader to be used by all ModuleClassLoaders. A null value may be returned if this hook does not supply the parent. Only one hook is able to provide the implementation of the parent class loader and the first one to return non-null wins.

Parameters:

configuration - the equinox configuration

Returns:

the parent class loader to be used by all ModuleClassLoaders