org.diet4j.core

Class AbstractModuleRegistry

java.lang.Object

org.diet4j.core.ModuleRegistry

org.diet4j.core.AbstractModuleRegistry

Direct Known Subclasses:

AbstractScanningModuleRegistry

public abstract class AbstractModuleRegistry
extends ModuleRegistry

Collects functionality common to implementations of ModuleRegistry.

Field Summary

Fields

Modifier and Type	Field and Description
static String[]	DEFAULT_DO_NOT_LOAD_CLASS_PREFIXES Only load classes with this prefix from the default ClassLoader.
protected Object	RESOLVE_LOCK This object is used as a semaphore for Module loads.
protected String[]	theDoNotLoadClassPrefixes Always load classes with these prefixes through the default ClassLoader.

Fields inherited from class org.diet4j.core.ModuleRegistry

theSingleton

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractModuleRegistry(String[] doNotLoadClassPrefixes) Constructor.

Method Summary

Modifier and Type	Method and Description
void	addModuleRegistryListener(ModuleRegistryListener newListener) Add a ModuleRegistry listener to be notified when new Modules become available etc.
protected ClassLoader	createClassLoader(Module module, ClassLoader parentClassLoader) ModuleRegistries can also acts as a factory for the Modules' ClassLoaders.
Module[]	determineRuntimeDependencies(Module theModule) Given a Module, this allows us to determine which other Modules it depends at run-time.
Module[]	determineRuntimeUses(Module theModule) Given a Module, this allows us to determine which other Modules use it at run-time.
ModuleMeta	determineSingleResolutionCandidate(ModuleRequirement req) Convenience method to determine the one and only ModuleMeta that is the only candidate to resolve a Module dependency, based on the knowledge of this ModuleRegistry.
protected void	fireModuleAddedEvent(ModuleRegistryEvent theEvent) Send an event to our listeners.
Module	getResolutionOf(ModuleMeta meta) Determine whether a certain ModuleMeta is resolved already, and if so, return it.
void	removeModuleRegistryListener(ModuleRegistryListener oldListener) Remove a ModuleRegistry listener.
Module	resolve(ModuleMeta meta) Recursively resolve this ModuleMeta into a Module.
Module	resolve(ModuleMeta meta, boolean recursive) Resolve this ModuleMeta into a Module.
String	toString() Obtain String representation.

Methods inherited from class org.diet4j.core.ModuleRegistry

determineResolutionCandidates, getSingleton, nameSet, nameSet

Methods inherited from class java.lang.Object

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

Field Detail

theDoNotLoadClassPrefixes

protected String[] theDoNotLoadClassPrefixes

Always load classes with these prefixes through the default ClassLoader.

RESOLVE_LOCK

protected final Object RESOLVE_LOCK

This object is used as a semaphore for Module loads.

DEFAULT_DO_NOT_LOAD_CLASS_PREFIXES

public static final String[] DEFAULT_DO_NOT_LOAD_CLASS_PREFIXES

Only load classes with this prefix from the default ClassLoader. It would be really nice if those were easier to determine, but javax.servlet, for example, is defined in Jetty as well.

Constructor Detail

AbstractModuleRegistry

protected AbstractModuleRegistry(String[] doNotLoadClassPrefixes)

Constructor.

Parameters:

doNotLoadClassPrefixes - prefixes of classes always to be loaded through the system class loader, not this one

Method Detail

determineSingleResolutionCandidate

public final ModuleMeta determineSingleResolutionCandidate(ModuleRequirement req)
                                                    throws NoModuleResolutionCandidateException,
                                                           ModuleResolutionCandidateNotUniqueException

Convenience method to determine the one and only ModuleMeta that is the only candidate to resolve a Module dependency, based on the knowledge of this ModuleRegistry. If there is more or less than one match, thrown an Exception.

Specified by:

determineSingleResolutionCandidate in class ModuleRegistry

Parameters:

req - the ModuleRequirement that we attempt to resolve

Returns:

the ModuleMeta that is the only candidate for the resolution of the ModuleRequirement

Throws:

NoModuleResolutionCandidateException - thrown if no ModuleMeta was found

ModuleResolutionCandidateNotUniqueException - thrown if there were more than one ModuleMeta found

resolve

public final Module resolve(ModuleMeta meta)
                     throws ModuleNotFoundException,
                            ModuleResolutionException

Recursively resolve this ModuleMeta into a Module.

Specified by:

resolve in class ModuleRegistry

Parameters:

meta - the ModuleMeta to resolve

Returns:

the resolved Module.

Throws:

ModuleNotFoundException - thrown if the Module could not be found

ModuleResolutionException - thrown if the Module could not be resolved

resolve

public final Module resolve(ModuleMeta meta,
                            boolean recursive)
                     throws ModuleNotFoundException,
                            ModuleResolutionException

Resolve this ModuleMeta into a Module.

Specified by:

resolve in class ModuleRegistry

Parameters:

meta - the ModuleMeta to resolve

recursive - resolve recursively if set to true

Returns:

the resolved Module.

Throws:

ModuleNotFoundException - thrown if the Module could not be found

ModuleResolutionException - thrown if the Module could not be resolved

getResolutionOf

public final Module getResolutionOf(ModuleMeta meta)

Determine whether a certain ModuleMeta is resolved already, and if so, return it. Do not attempt to resolve.

Specified by:

getResolutionOf in class ModuleRegistry

Parameters:

meta - the ModuleMeta whose resolution we check

Returns:

the Module to which the ModuleMeta has been resolved already, or null if not

determineRuntimeDependencies

public final Module[] determineRuntimeDependencies(Module theModule)

Given a Module, this allows us to determine which other Modules it depends at run-time. This is similar to the result of determineResolutionCandidates(), except that this returns one resolved Module for each dependency, not a set of ModuleMetas that may or may not be resolvable.

Specified by:

determineRuntimeDependencies in class ModuleRegistry

Parameters:

theModule - the Module whose run-time dependencies we want to determine

Returns:

the set of Modules that this Module depends on at run-time

See Also:

ModuleRegistry.determineRuntimeUses(org.diet4j.core.Module)

determineRuntimeUses

public final Module[] determineRuntimeUses(Module theModule)

Given a Module, this allows us to determine which other Modules use it at run-time. This is the inverse relationship found by determineRuntimeDependencies. However, unlike determineRuntimeDependencies, the returned values may change dramatically during operation of the system as additional Modules become users.

Specified by:

determineRuntimeUses in class ModuleRegistry

Parameters:

theModule - the Module whose uses we want to determine at run-time

Returns:

the set of Modules that this Module currently is used by at run-time

See Also:

ModuleRegistry.determineRuntimeDependencies(org.diet4j.core.Module)

createClassLoader

protected ClassLoader createClassLoader(Module module,
                                        ClassLoader parentClassLoader)

ModuleRegistries can also acts as a factory for the Modules' ClassLoaders.

Specified by:

createClassLoader in class ModuleRegistry

Parameters:

module - the Module for which to create a ClassLoader

parentClassLoader - the ClassLoader to use as the parent ClassLoader

Returns:

the ClassLoader to use with the Module

addModuleRegistryListener

public final void addModuleRegistryListener(ModuleRegistryListener newListener)

Add a ModuleRegistry listener to be notified when new Modules become available etc.

Specified by:

addModuleRegistryListener in class ModuleRegistry

Parameters:

newListener - the new listener to add

See Also:

ModuleRegistry.removeModuleRegistryListener(org.diet4j.core.ModuleRegistryListener)

removeModuleRegistryListener

public final void removeModuleRegistryListener(ModuleRegistryListener oldListener)

Remove a ModuleRegistry listener.

Specified by:

removeModuleRegistryListener in class ModuleRegistry

Parameters:

oldListener - the listener to remove

See Also:

ModuleRegistry.addModuleRegistryListener(org.diet4j.core.ModuleRegistryListener)

fireModuleAddedEvent

protected final void fireModuleAddedEvent(ModuleRegistryEvent theEvent)

Send an event to our listeners.

Parameters:

theEvent - the event to send

toString

public String toString()

Obtain String representation.

Overrides:

toString in class Object

Returns:

String representation