org.diet4j.core

Class Module

java.lang.Object

org.diet4j.core.Module

public class Module
extends Object

A software Module. On an operating system level, this is usually called package.

Field Summary

Fields

Modifier and Type	Field and Description
static String	RUN_METHOD_NAME Name of the run method on a class.
protected ClassLoader	theClassLoader This Module's ClassLoader.
protected ModuleMeta	theModuleMeta The ModuleMeta for this Module.
protected ClassLoader	theParentClassLoader The parent ClassLoader of this Module's ClassLoader.
protected ModuleRegistry	theRegistry The AbstractModuleRegistry in which this Module is registered.

Constructor Summary

Constructors

Constructor and Description
Module(ModuleMeta meta, AbstractModuleRegistry registry, ClassLoader parentClassLoader) Constructor.

Method Summary

Modifier and Type	Method and Description
void	activateRecursively() This recursively activates this Module.
void	activateRecursively(ModuleActivator activator) This recursively activates this Module.
void	deactivateRecursively() This recursively deactivates this Module.
void	deactivateRecursively(ModuleActivator activator) This recursively deactivates this Module.
Module[]	determineRuntimeDependencies() Convenience method to determine the dependent Modules of this Module at run-time.
Module[]	determineRuntimeUses() Convenience method to determine the Modules that use this Module at run-time.
boolean	equals(Object other) Determine Module equality.
ClassLoader	getClassLoader() Obtain a ClassLoader that knows how to load the code belonging to this Module.
Object	getContextObject() Obtain the context object returned by the activation method of this Module, if any.
ModuleActivator	getDefaultModuleActivator() Obtain the default ModuleActivator for this Module.
String	getModuleArtifactId() Obtain the artifactId of this Module.
String	getModuleGroupId() Obtain the groupId of this Module.
ModuleMeta	getModuleMeta() Obtain the ModuleMeta for this Module.
ModuleRegistry	getModuleRegistry() Obtain the ModuleRegistry in which this Module has been registered.
String	getModuleVersion() Obtain the version of this Module.
int	hashCode() Determine hash code.
boolean	isActive() Determine whether this Module is active.
void	run(String[] arguments) Run this Module as a root Module.
int	run(String overriddenRunClassName, String overriddenRunMethodName, String[] arguments) Run this Module as a root Module.
String	toString() For debugging.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

theRegistry

protected ModuleRegistry theRegistry

The AbstractModuleRegistry in which this Module is registered.

theModuleMeta

protected ModuleMeta theModuleMeta

The ModuleMeta for this Module.

theClassLoader

protected ClassLoader theClassLoader

This Module's ClassLoader. Allocated as needed.

theParentClassLoader

protected ClassLoader theParentClassLoader

The parent ClassLoader of this Module's ClassLoader.

RUN_METHOD_NAME

public static final String RUN_METHOD_NAME

Name of the run method on a class.

See Also:

Constant Field Values

Constructor Detail

Module

public Module(ModuleMeta meta,
              AbstractModuleRegistry registry,
              ClassLoader parentClassLoader)

Constructor. This should not be directly invoked by the application programmer.

Parameters:

meta - this Module's ModuleMeta

registry - the registry of Modules in which we try to find dependent Modules

parentClassLoader - the class loader of our parent Module

Method Detail

getModuleGroupId

public final String getModuleGroupId()

Obtain the groupId of this Module. It is the same as the groupId of its ModuleMeta.

Returns:

the groupId of this Module

getModuleArtifactId

public final String getModuleArtifactId()

Obtain the artifactId of this Module. It is the same as the artifactId of its ModuleMeta.

Returns:

the artifactId of this Module

getModuleVersion

public final String getModuleVersion()

Obtain the version of this Module. It is the same as the version of its ModuleMeta.

Returns:

the version of this Module

getModuleMeta

public final ModuleMeta getModuleMeta()

Obtain the ModuleMeta for this Module.

Returns:

the ModuleMeta for this Module

getModuleRegistry

public final ModuleRegistry getModuleRegistry()

Obtain the ModuleRegistry in which this Module has been registered.

Returns:

the ModuleRegistry in which this Module has been registered

determineRuntimeDependencies

public final Module[] determineRuntimeDependencies()

Convenience method to determine the dependent Modules of this Module at run-time.

Returns:

the dependent Modules at run-time

determineRuntimeUses

public final Module[] determineRuntimeUses()

Convenience method to determine the Modules that use this Module 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.

Returns:

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

getClassLoader

public final ClassLoader getClassLoader()
                                 throws MalformedURLException

Obtain a ClassLoader that knows how to load the code belonging to this Module. This ClassLoader will delegate to the ClassLoader of the parent Module.

Returns:

this Module's ClassLoader

Throws:

MalformedURLException - thrown if one of the URLs identifying the Module's JAR files is malformed

isActive

public final boolean isActive()

Determine whether this Module is active. A Module is active if it has been activated and not deactivated afterwards.

Returns:

if true, this Module is active

activateRecursively

public final void activateRecursively()
                               throws ModuleResolutionException,
                                      ModuleNotFoundException,
                                      ModuleActivationException

This recursively activates this Module. First, this method recursively activates all Modules that it this Module depends on, and then it activates itself.

Throws:

ModuleResolutionException - thrown if a dependent Module cannot be resolved

ModuleNotFoundException - thrown if a dependent Module cannot be found

ModuleActivationException - thrown if this Module, or a dependent Module could not be activated

activateRecursively

public final void activateRecursively(ModuleActivator activator)
                               throws ModuleResolutionException,
                                      ModuleNotFoundException,
                                      ModuleActivationException

This recursively activates this Module. First, this method recursively activates all Modules that it this Module depends on, and then it activates itself. By specifying a ModuleActivator, a non-standard way of activating the Module can be performed.

Parameters:

activator - a ModuleActivator instance that knows how to activate this Module

Throws:

ModuleResolutionException - thrown if a dependent Module cannot be resolved

ModuleNotFoundException - thrown if a dependent Module cannot be found

ModuleActivationException - thrown if this Module, or a dependent Module could not be activated

deactivateRecursively

public final void deactivateRecursively()
                                 throws ModuleDeactivationException

This recursively deactivates this Module. First, this method deactivates itself, and then it recursively activates all Modules that this Module depends on

Throws:

ModuleDeactivationException - throws if the Module could not be deactivated

deactivateRecursively

public final void deactivateRecursively(ModuleActivator activator)
                                 throws ModuleDeactivationException

This recursively deactivates this Module. First, this method deactivates itself, and then it recursively activates all Modules that this Module depends on. By specifying a ModuleActivator, a non-standard way of deactivating the Module can be performed.

Parameters:

activator - a ModuleActivator instance that knows how to deactivate instead of the default one specified in the ModuleMeta

Throws:

ModuleDeactivationException - throws if the Module could not be deactivated

getContextObject

public final Object getContextObject()

Obtain the context object returned by the activation method of this Module, if any.

Returns:

the context object, or null

run

public final void run(String[] arguments)
               throws ClassNotFoundException,
                      ModuleRunException,
                      NoRunMethodException,
                      InvocationTargetException

Run this Module as a root Module.

Parameters:

arguments - arguments to run, similar to the arguments of a standard main(...) method

Throws:

ClassNotFoundException - thrown if the specified run class cannot be found

ModuleRunException - thrown if the specified run method threw an Exception

NoRunMethodException - thrown if a suitable run method cannot be found

InvocationTargetException - thrown if the run method throws an Exception

run

public int run(String overriddenRunClassName,
               String overriddenRunMethodName,
               String[] arguments)
        throws ClassNotFoundException,
               ModuleRunException,
               NoRunMethodException,
               InvocationTargetException

Run this Module as a root Module. Specify a class to run other than the default, and/or a method other than the main() method.

Parameters:

overriddenRunClassName - optional name of the class to run instead of the default one specified in the ModuleMeta

overriddenRunMethodName - optional name of the method in the class to run instead of the default one specified in the ModuleMeta

arguments - arguments to run, similar to the arguments of a standard main(...) method

Returns:

the desired System exit code

Throws:

ClassNotFoundException - thrown if the specified run class cannot be found

ModuleRunException - thrown if the specified run method threw an Exception

NoRunMethodException - thrown if a suitable run method cannot be found

InvocationTargetException - thrown if the run method throws an Exception

getDefaultModuleActivator

public ModuleActivator getDefaultModuleActivator()

Obtain the default ModuleActivator for this Module.

Returns:

the ModuleActivator

equals

public boolean equals(Object other)

Determine Module equality. Two Modules are the same if they have the same Module Advertisement.

Overrides:

equals in class Object

Parameters:

other - other object to compare this Module to

Returns:

returns true if the objects are the same

hashCode

public int hashCode()

Determine hash code. We use the hash code of our ModuleMeta.

Overrides:

hashCode in class Object

Returns:

the hash code

toString

public String toString()

For debugging.

Overrides:

toString in class Object

Returns:

string representation of this object