Class ModuleLoader

java.lang.Object
org.jboss.modules.ModuleLoader
Direct Known Subclasses:
ClassifyingModuleLoader, DelegatingModuleLoader

public class ModuleLoader extends Object
A repository for modules, from which a module may be loaded by identifier. Module loaders may additionally delegate to one or more other module loaders.
Author:
David M. Lloyd, John Bailey, Richard Opalka, Jason T. Greene
  • Field Details

    • NO_FINDERS

      public static final ModuleFinder[] NO_FINDERS
      A constant representing zero module finders.
  • Constructor Details

    • ModuleLoader

      protected ModuleLoader()
      Construct a new instance.
    • ModuleLoader

      public ModuleLoader(ModuleFinder[] finders)
      Construct a new instance.
      Parameters:
      finders - the module finders to search, in order
    • ModuleLoader

      public ModuleLoader(ModuleFinder finder)
      Construct a new instance.
      Parameters:
      finder - the single module finder to search (must not be null)
  • Method Details

    • forClass

      public static ModuleLoader forClass(Class<?> clazz)
      Get the module loader for a class.
      Parameters:
      clazz - the class
      Returns:
      the module loader or null if the class's class loader does not belong to a module loader.
    • forClassLoader

      public static ModuleLoader forClassLoader(ClassLoader classLoader)
      Get the module loader for a class loader.
      Parameters:
      classLoader - the class loader
      Returns:
      the module loader or null if the class loader does not belong to a module loader.
    • toString

      public String toString()
      Get the string representation of this module loader.
      Overrides:
      toString in class Object
      Returns:
      the string representation
    • getModuleDescription

      public String getModuleDescription(Module module)
      Get a string representation of the given module, used in debug output and stack traces. This method may be overridden to provide a more detailed description. By default it returns a string consisting of the module's name and version (if any).
      Parameters:
      module - the module to describe
      Returns:
      the description string
    • installMBeanServer

      public static void installMBeanServer()
      Install JBoss Modules MBeans. WARNING: This method is not intended to be called by application code.
    • loadModule

      @Deprecated(forRemoval=true) public final Module loadModule(ModuleIdentifier identifier) throws ModuleLoadException
      Deprecated, for removal: This API element is subject to removal in a future version.
      Use loadModule(String) instead.
      Load a module based on an identifier. This method delegates to preloadModule(String) and then links the returned module if necessary.
      Parameters:
      identifier - The module identifier
      Returns:
      The loaded Module
      Throws:
      ModuleLoadException - if the Module can not be loaded
    • loadModule

      public final Module loadModule(String name) throws ModuleLoadException
      Load a module based on an identifier. This method delegates to preloadModule(String) and then links the returned module if necessary.
      Parameters:
      name - The module name
      Returns:
      The loaded Module
      Throws:
      ModuleLoadException - if the Module can not be loaded
    • iterateModules

      @Deprecated(forRemoval=true) public final Iterator<ModuleIdentifier> iterateModules(ModuleIdentifier baseIdentifier, boolean recursive)
      Deprecated, for removal: This API element is subject to removal in a future version.
      Iterate the modules which can be located via this module loader.
      Parameters:
      baseIdentifier - the identifier to start with, or null to iterate all modules
      recursive - true to find recursively nested modules, false to only find immediately nested modules
      Returns:
      an iterator for the modules in this module finder
      Throws:
      SecurityException - if the caller does not have permission to iterate module loaders
    • iterateModules

      public final Iterator<String> iterateModules(String baseName, boolean recursive)
      Iterate the modules which can be located via this module loader.
      Parameters:
      baseName - the identifier to start with, or null to iterate all modules; ignored if this module loader does not have a concept of nested modules
      recursive - true to find recursively nested modules, false to only find immediately nested modules; ignored if this module finder does not have a concept of nested modules
      Returns:
      an iterator for the modules in this module finder
      Throws:
      SecurityException - if the caller does not have permission to iterate module loaders
    • preloadModule

      @Deprecated(forRemoval=true) protected Module preloadModule(ModuleIdentifier identifier) throws ModuleLoadException
      Deprecated, for removal: This API element is subject to removal in a future version.
      This compatibility method just calls preloadModule(methodIdentifier.toString()) and is usually not used; if however a legacy subclass overrides this method, then it will be called instead of preloadModule(String), and that method will redirect to this one.
      Parameters:
      identifier - the module identifier (must not be null)
      Returns:
      the load result, or null if the module is not found
      Throws:
      ModuleLoadException - if an error occurs
    • preloadModule

      protected Module preloadModule(String name) throws ModuleLoadException
      Preload a module based on an identifier. By default, delegation is only done for system and this method otherwise simply invokes loadModuleLocal(String). A delegating module loader may delegate to the appropriate module loader based on loader-specific criteria (via the preloadModule(String, ModuleLoader) method).
      Parameters:
      name - the module identifier
      Returns:
      the load result, or null if the module is not found
      Throws:
      ModuleLoadException - if an error occurs
    • preloadExportedModule

      protected Module preloadExportedModule(String name) throws ModuleLoadException
      Preload an "exported" module based on an identifier. By default this simply delegates to preloadModule(String).
      Parameters:
      name - the module name
      Returns:
      the load result, or null if the module is not found
      Throws:
      ModuleLoadException - if an error occurs
    • preloadExportedModule

      @Deprecated(forRemoval=true) protected Module preloadExportedModule(ModuleIdentifier identifier) throws ModuleLoadException
      Deprecated, for removal: This API element is subject to removal in a future version.
      Preload an "exported" module based on an identifier. By default this simply delegates to preloadModule(String).
      Parameters:
      identifier - the module identifier
      Returns:
      the load result, or null if the module is not found
      Throws:
      ModuleLoadException - if an error occurs
    • preloadModule

      protected static Module preloadModule(String name, ModuleLoader moduleLoader) throws ModuleLoadException
      Utility method to delegate to another module loader, accessible from subclasses. The delegate module loader will be queried for exported modules only.
      Parameters:
      name - the module name
      moduleLoader - the module loader to delegate to
      Returns:
      the delegation result
      Throws:
      ModuleLoadException - if an error occurs
    • preloadModule

      @Deprecated(forRemoval=true) protected static Module preloadModule(ModuleIdentifier identifier, ModuleLoader moduleLoader) throws ModuleLoadException
      Deprecated, for removal: This API element is subject to removal in a future version.
      Utility method to delegate to another module loader, accessible from subclasses. The delegate module loader will be queried for exported modules only.
      Parameters:
      identifier - the module identifier
      moduleLoader - the module loader to delegate to
      Returns:
      the delegation result
      Throws:
      ModuleLoadException - if an error occurs
    • loadModuleLocal

      @Deprecated(forRemoval=true) protected final Module loadModuleLocal(ModuleIdentifier moduleIdentifier) throws ModuleLoadException
      Deprecated, for removal: This API element is subject to removal in a future version.
      Try to load a module from this module loader. Returns null if the module is not found. The returned module may not yet be resolved. The returned module may have a different name than the given identifier if the identifier is an alias for another module.
      Parameters:
      moduleIdentifier - the module identifier
      Returns:
      the module
      Throws:
      ModuleLoadException - if an error occurs while loading the module
    • loadModuleLocal

      protected final Module loadModuleLocal(String name) throws ModuleLoadException
      Try to load a module from this module loader. Returns null if the module is not found. The returned module may not yet be resolved. The returned module may have a different name than the given identifier if the identifier is an alias for another module.
      Parameters:
      name - the module name
      Returns:
      the module
      Throws:
      ModuleLoadException - if an error occurs while loading the module
    • findLoadedModuleLocal

      @Deprecated(forRemoval=true) protected final Module findLoadedModuleLocal(ModuleIdentifier identifier)
      Deprecated, for removal: This API element is subject to removal in a future version.
      Find an already-loaded module, returning null if the module isn't currently loaded. May block while the loaded state of the module is in question (if the module is being concurrently loaded from another thread, for example).
      Parameters:
      identifier - the module identifier
      Returns:
      the module, or null if it wasn't found
    • findLoadedModuleLocal

      protected final Module findLoadedModuleLocal(String name)
      Find an already-loaded module, returning null if the module isn't currently loaded. May block while the loaded state of the module is in question (if the module is being concurrently loaded from another thread, for example).
      Parameters:
      name - the module identifier
      Returns:
      the module, or null if it wasn't found
    • unloadModuleLocal

      @Deprecated protected final void unloadModuleLocal(Module module) throws SecurityException
      Deprecated.
      Unload a module from this module loader. Note that this has no effect on existing modules which refer to the module being unloaded. Also, only modules from the current module loader can be unloaded. Unloading the same module more than once has no additional effect. This method only removes the mapping for the module; any running threads which are currently accessing or linked to the module will continue to function, however attempts to load this module will fail until a new module is loaded with the same name. Once this happens, if all references to the previous module are not cleared, the same module may be loaded more than once, causing possible class duplication and class cast exceptions if proper care is not taken.
      Parameters:
      module - the module to unload
      Throws:
      SecurityException - if an attempt is made to unload a module which does not belong to this module loader
      SecurityException - if the module was not defined by this module loader
    • unloadModuleLocal

      protected final boolean unloadModuleLocal(String moduleId, Module module) throws SecurityException
      Unload a module from this module loader. Note that this has no effect on existing modules which refer to the module being unloaded. Also, only modules from the current module loader can be unloaded. Unloading the same module more than once has no additional effect. This method only removes the mapping for the module; any running threads which are currently accessing or linked to the module will continue to function, however attempts to load this module will fail until a new module is loaded with the same name. Once this happens, if all references to the previous module are not cleared, the same module may be loaded more than once, causing possible class duplication and class cast exceptions if proper care is not taken.

      If the given moduleName is an alias of the given module then only alias mapping to module is removed. Aliased module with its canonical name and other aliases mapping is left intact.

      If the given moduleName is the canonical module name then all its alias plus canonical moduleName association mappings are removed.

      Parameters:
      moduleId - the module identifier
      module - the module to unload
      Returns:
      true iff module was unloaded
      Throws:
      SecurityException - if an attempt is made to unload a module which does not belong to this module loader
      SecurityException - if the module was not defined by this module loader
    • findModule

      @Deprecated(forRemoval=true) protected ModuleSpec findModule(ModuleIdentifier moduleIdentifier) throws ModuleLoadException
      Deprecated, for removal: This API element is subject to removal in a future version.
      Use findModule(String) instead.
      This compatibility method just calls findModule(methodIdentifier.toString()) and is usually not used; if however a legacy subclass overrides this method, then it will be called instead of findModule(String), and that method will redirect to this one.
      Parameters:
      moduleIdentifier - the module identifier
      Returns:
      the module specification
      Throws:
      ModuleLoadException
    • findModule

      protected ModuleSpec findModule(String name) throws ModuleLoadException
      Find a Module's specification in this ModuleLoader by its name. This can be overriden by sub-classes to implement the Module loading strategy for this loader. The default implementation iterates the module finders provided during construction.

      If no module is found in this module loader with the given identifier, then this method should return null. If the module is found but some problem occurred (for example, a transitive dependency failed to load) then this method should throw a ModuleLoadException of the relevant type.

      Parameters:
      name - the module name
      Returns:
      the module specification, or null if no module is found with the given identifier
      Throws:
      ModuleLoadException - if any problems occur finding the module
    • getFinders

      protected final ModuleFinder[] getFinders()
      Get the module finders configured for this module loader.
      Returns:
      the module finders
    • refreshResourceLoaders

      protected void refreshResourceLoaders(Module module)
      Refreshes the paths provided by resource loaders associated with the specified Module. This is an advanced method that is intended to be called on modules that have a resource loader implementation that has changed and is returning different paths.
      Parameters:
      module - the module to refresh
      Throws:
      SecurityException - if the module was not defined by this module loader, or if the module loader does not have the required permissions associated with it
    • setAndRefreshResourceLoaders

      protected void setAndRefreshResourceLoaders(Module module, Collection<ResourceLoaderSpec> loaders)
      Replaces the resources loaders for the specified module and refreshes the internal path list that is derived from the loaders. This is an advanced method that should be used carefully, since it alters a live module. Modules that import resources from the specified module will not automatically be updated to reflect the change. For this to occur relink(Module) must be called on all of them.
      Parameters:
      module - the module to update and refresh
      loaders - the new collection of loaders the module should use
      Throws:
      SecurityException - if the module was not defined by this module loader, or if the module loader does not have the required permissions associated with it
    • relink

      protected void relink(Module module) throws ModuleLoadException
      Relinks the dependencies associated with the specified Module. This is an advanced method that is intended to be called on all modules that directly or indirectly import dependencies that are re-exported by a module that has recently been updated and relinked via setAndRelinkDependencies(Module, java.util.List).
      Parameters:
      module - the module to relink
      Throws:
      ModuleLoadException - if relinking failed
      SecurityException - if the module was not defined by this module loader, or if the module loader does not have the required permissions associated with it
    • setAndRelinkDependencies

      protected void setAndRelinkDependencies(Module module, List<DependencySpec> dependencies) throws ModuleLoadException
      Replaces the dependencies for the specified module and relinks against the new modules This is an advanced method that should be used carefully, since it alters a live module. Modules that import dependencies that are re-exported from the specified module will not automatically be updated to reflect the change. For this to occur relink(Module) must be called on all of them.
      Parameters:
      module - the module to update and relink
      dependencies - the new dependency list
      Throws:
      ModuleLoadException - if relinking failed
      SecurityException - if the module was not defined by this module loader, or if the module loader does not have the required permissions associated with it
    • getDependencies

      protected DependencySpec[] getDependencies(Module module)
      Get the current dependency list for a module which was defined by this module loader, without any access checks.
      Returns:
      the current dependency list for the module
      Throws:
      SecurityException - if the module was not defined by this module loader