Now as we handled the basics of the JCE and our concepts to enable smartcard based providers we can discuss our manager instances which already implement the most of the logic to create, register and return our providers.
ReaderManager
The ReaderManager is the most important class within our framework. It communicates with the system via the ModuleManager and manages all available readers. It offers different services which are necessary to create a SmartCardAuthProvider. We now should exemplarily go through these services step by step:
- First an instance of the ModuleManager interface has to be declared to the ReaderManager. See 3.2 for detailed information of the ModuleManager's tasks. The declaration is executed by calling setModuleManager.
- This will lead the ReaderManager to receive the ModuleManagers default module and automatically register it by calling registerNewModule.
Modules are kind of drivers responsible for communicating with a smartcard-reader / smartcard. Each module is able to communicate with a set of smartcard-readers connected to the system. The combination Module / Reader is a unique identifier which lets the ReaderManager know which module it shall use in order to communicate with a reader. Two distinct modules can also share a reader. The ReaderModuleDescription stores this unique identifier and is used by the ReaderManager to address the readers via different modules (drivers).
For each module registered to the ReaderManager a new thread is started which listens to reader events. See 2.4.2 for details about reader events.
A module can be also unregistered by calling unregisterModule. This would stop the module's listening thread and detach all the readers managed by the module. Readers shared with other modules would still be accessible by the other modules.
As soon as a module is registered to the ReaderManager the readers adressed by the module are accessible via the ReaderManager.
- Now a module is registerd and the ReaderManager is able to address some readers. Next we can call getSystemReaders which returns us all ReaderModuleDescriptions currently available.
- With such a ReaderModuleDescription we can attach a reader by calling attachReader. This call will create a reader instance which is exclisivly reserved and can not be generated a second time. With this reader instance we can create a SmartCardAuthProvider.
We can also detach a reader by calling detachReader. The reader then sends a signal to all its observers that the reader has been detached. The SmartCardAuthProvider listening to that reader then stops operating.
Other features offered by the ReaderManager are:
- setSystemEventHandler
The systemEventHandler is able to react on reader-added and reader-removed events triggered by the ReaderManager. This function registers the handler at the ReaderManager. The interface is implemented by the SmartCardAuthProviderManager (see 3.3).
- getDetachedReaders
This function returns all the readers that have not been reserved by attachReader.
- getAttachedReaders
This function returns all the readers that have been previously reserved by attachReader.
- unregisterAllModules
This function unregisters all modules currently registered. See 2.)
- isSmartCardInserted
This function returns wheter a smartcard is inserted for the given ReaderModuleDescription.
- getFirstAdditionallyReader
Additionally readers can be pre-configured. An additionally reader is a reader which is not directly avaible to the system but may will be accessible in the future such as a e.g. bluetooth reader. So even for those readers which are currently not present providers can be created.
Additionally readers are linked to each module i.e. when two additionally readers are pre-configured and three modules registered there are at least six ReaderModuleDescriptions available at the ReaderManager.
This function returns the very first of it where the order depends on the registration order of the modules and the configuration order of the additionally readers.
ModuleManager / P11ModuleManager
The ModuleManager shall the ModuleManager is an interface be responsible for managing different modules. The instance's tasks are:
- getDefaultModules
The ModuleManager shall be able to at least return one default module i.e. it shall be shipped with at least one driver able for communicating with smartcard-readers.
- getDefaultAdditionalReaders
See 3.1 for description of additionally readers. This function shall return the default ones.
- getDefaultAdditionalReaderInfo
Any reader contains ReaderInfo. In order to support that feature for additional (unconnected) readers this function shall return the ReaderInfo for an additionally reader.
- registerModule
Readers connected to the system shall be addressable by different modules / drivers. This functions registers a new module and shall enable communication with supported readers.
- unregisterModule
This function shall (detach and) remove all readers addressable by that module.
- getRegisteredModule
Shall return all registered modules.
- getCompatibleReaders
Shall return all readers which are addressable by the given module.
- existsReader
Shall check whether the reader exists / is addressable.
- isAdditionallyReader
Shall check whether the reader is an additionally reader.
- getReaderState
Shall check the state of the reader.
- getReaderInfo
Shall return the reader info.
- getModuleInfo
Shall return the module info.
- getSmartcard
Shall create a smartcard instance.
- waitForModuleEvent
Shall wait until an event happens like – reader added, reader removed, smartcard inserted into reader, smartcard removed out of reader.
The ModuleManager interface is implemented by the P11ModuleManager which uses the cgPKCS#11 in order to communicate with smartcards. The cgPKCS#11 can be seen as a single module and is used as default module by the P11ModuleManager.
SmartCardAuthProviderManager
The SmartCardAuthProviderManager offers the opportunity to do all the steps 1. – 5. shown in 3.1 automatically. The offered services are:
- registerSmartCardProvider
A SmartCardAuthProvider is automatically registered to the system. First the provider is created and then registered by Security.addProvider.
- unregisterSmartCardProvider
First the reader the provider is listening to is detached. Then the provider is unregisted at the system by calling Security.removeProvider. On detach all objects returned by the provider are signaled that the reader was detached. These objects are no more useable. Accessing such an object will fail with an exception.
- registerAllAvailableProviders
Creates and registers SmartCardAuthProviders for each ReaderModuleDescription which is available and has not been attached in the system.
- getRegisteredSmartCardProviders
Returns all available SmartCardAuthProviders which where registered by the SmartCardAuthProviderManager. SmartCardAuthProviders created and registered manually are not returned.
- getAdditionallyRegisteredSmartCardProviders
Returns a subset of providers which are based on additionally readers. This subset is also included in getAdditionallyRegisteredSmartCardProviders
- getRegisteredSmartCardProvidersWithSmartCardInserted
Returns all SmartCardAuthProviders which are ready to use / have a smartcard inserted.
Furthermore the SmartCardAuthProviderManager implements the SystemEventHandler-interface and selfregisteres as soon as getInstance was called once. Otherwise the SmartCardAuthProviderManager stays uninitialized and does not react on events. at the ReaderManager which makes it capable of receiving reader-added and reader-removed events.
- onSystemEventReaderAdded
When a new reader is added to the system and the SmartCardAuthProviderManager was called once before a new provider is automatically added to the system.
- onSystemEventReaderRemoved
When a reader was removed and the SmartCardAuthProviderManager was called once before the provider is unregistered from the system.