C++ Micro Services: Module Class Reference
Module Class Reference

Represents a CppMicroServices module. More...

Public Member Functions

 ~Module ()
 
bool IsLoaded () const
 Returns this module's current state. More...
 
ModuleContextGetModuleContext () const
 Returns this module's ModuleContext. More...
 
long GetModuleId () const
 Returns this module's unique identifier. More...
 
std::string GetLocation () const
 Returns this module's location. More...
 
std::string GetName () const
 Returns the name of this module as specified by the US_CREATE_MODULE CMake macro. More...
 
ModuleVersion GetVersion () const
 Returns the version of this module as specified by the US_INITIALIZE_MODULE CMake macro. More...
 
Any GetProperty (const std::string &key) const
 Returns the value of the specified property for this module. More...
 
std::vector< std::string > GetPropertyKeys () const
 Returns a list of top-level property keys for this module. More...
 
std::vector< ServiceReferenceGetRegisteredServices () const
 Returns this module's ServiceReference list for all services it has registered or an empty list if this module has no registered services. More...
 
std::vector< ServiceReferenceGetServicesInUse () const
 Returns this module's ServiceReference list for all services it is using or returns an empty list if this module is not using any services. More...
 
ModuleResource GetResource (const std::string &path) const
 Returns the resource at the specified path in this module. More...
 
std::vector< ModuleResourceFindResources (const std::string &path, const std::string &filePattern, bool recurse) const
 Returns resources in this module and its statically linked modules. More...
 

Static Public Member Functions

static const std::string & PROP_ID ()
 Returns the property key for looking up this module's id. More...
 
static const std::string & PROP_NAME ()
 Returns the property key for looking up this module's name. More...
 
static const std::string & PROP_LOCATION ()
 Returns the property key for looking up this module's location the file system. More...
 
static const std::string & PROP_VERSION ()
 Returns the property key with a value of module.version for looking up this module's version identifier. More...
 
static const std::string & PROP_VENDOR ()
 Returns the property key with a value of module.vendor for looking up this module's vendor information. More...
 
static const std::string & PROP_DESCRIPTION ()
 Returns the property key with a value of module.description for looking up this module's description. More...
 
static const std::string & PROP_AUTOLOAD_DIR ()
 Returns the property key with a value of module.autoload_dir for looking up this module's auto-load directory. More...
 

Detailed Description

Represents a CppMicroServices module.

A Module object is the access point to a CppMicroServices module. Each CppMicroServices module has an associated Module object.

A module has unique identity, a long, chosen by the framework. This identity does not change during the lifecycle of a module.

A module can be in one of two states:

  • LOADED
  • UNLOADED

You can determine the current state by using IsLoaded().

A module can only execute code when its state is LOADED. An UNLOADED module is a zombie and can only be reached because it was loaded before. However, unloaded modules can be loaded again.

The framework is the only entity that is allowed to create Module objects.

Remarks
This class is thread safe.

Constructor & Destructor Documentation

Module::~Module ( )

Member Function Documentation

std::vector<ModuleResource> Module::FindResources ( const std::string &  path,
const std::string &  filePattern,
bool  recurse 
) const

Returns resources in this module and its statically linked modules.

This method is intended to be used to obtain configuration, setup, localization and other information from this module.

This method can either return only resources in the specified path or recurse into subdirectories returning resources in the directory tree beginning at the specified path.

Examples:

ModuleContext* moduleContext = GetModuleContext();
Module* module = moduleContext->GetModule();
// List all XML files in the config directory
std::vector<ModuleResource> xmlFiles = module->FindResources("config", "*.xml", false);
// Find the resource named vertex_shader.txt starting at the root directory
std::vector<ModuleResource> shaders = module->FindResources("", "vertex_shader.txt", true);
Note
In case of modules statically linked into this module, the returned ModuleResource objects can represent the same resource path, coming from different static modules. The order of the ModuleResource objects in the returned container matches the order of the static module names in the US_LOAD_IMPORTED_MODULES macro.
Parameters
pathThe path name in which to look. The path is always relative to the root of this module and may begin with '/'. A path value of "/" indicates the root of this module.
filePatternThe resource name pattern for selecting entries in the specified path. The pattern is only matched against the last element of the resource path. Substring matching is supported using the wildcard charachter ('*'). If filePattern is empty, this is equivalent to "*" and matches all resources.
recurseIf true, recurse into subdirectories. Otherwise only return resources from the specified path.
Returns
A vector of ModuleResource objects for each matching entry. The objects are sorted such that resources from this module are returned first followed by the resources from statically linked modules in the load order as specified in US_LOAD_IMPORTED_MODULES.
std::string Module::GetLocation ( ) const

Returns this module's location.

The location is the full path to the module's shared library. This method continues to return this module's location while this module is in the UNLOADED state.

Returns
The string representation of this module's location.
ModuleContext* Module::GetModuleContext ( ) const

Returns this module's ModuleContext.

The returned ModuleContext can be used by the caller to act on behalf of this module.

If this module is not in the LOADED state, then this module has no valid ModuleContext. This method will return 0 if this module has no valid ModuleContext.

Returns
A ModuleContext for this module or 0 if this module has no valid ModuleContext.
long Module::GetModuleId ( ) const

Returns this module's unique identifier.

This module is assigned a unique identifier by the framework when it was loaded.

A module's unique identifier has the following attributes:

  • Is unique.
  • Is a long.
  • Its value is not reused for another module, even after a module is unloaded.
  • Does not change while a module remains loaded.
  • Does not change when a module is reloaded.

This method continues to return this module's unique identifier while this module is in the UNLOADED state.

Returns
The unique identifier of this module.
std::string Module::GetName ( ) const

Returns the name of this module as specified by the US_CREATE_MODULE CMake macro.

The module name together with a version must identify a unique module.

This method continues to return this module's name while this module is in the UNLOADED state.

Returns
The name of this module.
Any Module::GetProperty ( const std::string &  key) const

Returns the value of the specified property for this module.

The method returns an empty Any if the property is not found.

Parameters
keyThe name of the requested property.
Returns
The value of the requested property, or an empty string if the property is undefined.
See Also
GetPropertyKeys()
Module Properties
std::vector<std::string> Module::GetPropertyKeys ( ) const

Returns a list of top-level property keys for this module.

Returns
A list of available property keys.
See Also
Module Properties
std::vector<ServiceReference> Module::GetRegisteredServices ( ) const

Returns this module's ServiceReference list for all services it has registered or an empty list if this module has no registered services.

The list is valid at the time of the call to this method, however, as the framework is a very dynamic environment, services can be modified or unregistered at anytime.

Returns
A list of ServiceReference objects for services this module has registered.
ModuleResource Module::GetResource ( const std::string &  path) const

Returns the resource at the specified path in this module.

The specified path is always relative to the root of this module and may begin with '/'. A path value of "/" indicates the root of this module.

Note
In case of other modules being statically linked into this module, the path can be ambiguous and returns the first resource matching the provided path according to the order of the static module names in the US_LOAD_IMPORTED_MODULES macro.
Parameters
pathThe path name of the resource.
Returns
A ModuleResource object for the given path. If the path cannot be found in this module or the module's state is UNLOADED, an invalid ModuleResource object is returned.
std::vector<ServiceReference> Module::GetServicesInUse ( ) const

Returns this module's ServiceReference list for all services it is using or returns an empty list if this module is not using any services.

A module is considered to be using a service if its use count for that service is greater than zero.

The list is valid at the time of the call to this method, however, as the framework is a very dynamic environment, services can be modified or unregistered at anytime.

Returns
A list of ServiceReference objects for all services this module is using.
ModuleVersion Module::GetVersion ( ) const

Returns the version of this module as specified by the US_INITIALIZE_MODULE CMake macro.

If this module does not have a specified version then ModuleVersion::EmptyVersion is returned.

This method continues to return this module's version while this module is in the UNLOADED state.

Returns
The version of this module.
bool Module::IsLoaded ( ) const

Returns this module's current state.

A module can be in only one state at any time.

Returns
true if the module is LOADED false if it is UNLOADED
static const std::string& Module::PROP_AUTOLOAD_DIR ( )
static

Returns the property key with a value of module.autoload_dir for looking up this module's auto-load directory.

The property value is of type std::string.

Returns
The version property key.
static const std::string& Module::PROP_DESCRIPTION ( )
static

Returns the property key with a value of module.description for looking up this module's description.

The property value is of type std::string.

Returns
The version property key.
static const std::string& Module::PROP_ID ( )
static

Returns the property key for looking up this module's id.

The property value is of type long.

Returns
The id property key.
static const std::string& Module::PROP_LOCATION ( )
static

Returns the property key for looking up this module's location the file system.

The property value is of type std::string.

Returns
The location property key.
static const std::string& Module::PROP_NAME ( )
static

Returns the property key for looking up this module's name.

The property value is of type std::string.

Returns
The name property key.
static const std::string& Module::PROP_VENDOR ( )
static

Returns the property key with a value of module.vendor for looking up this module's vendor information.

The property value is of type std::string.

Returns
The version property key.
static const std::string& Module::PROP_VERSION ( )
static

Returns the property key with a value of module.version for looking up this module's version identifier.

The property value is of type std::string.

Returns
The version property key.