com.graphaware.runtime.manager

Class BaseModuleManager<M extends ModuleMetadata,T extends RuntimeModule>

java.lang.Object

com.graphaware.runtime.manager.BaseModuleManager<M,T>

All Implemented Interfaces:

ModuleManager<T>

Direct Known Subclasses:

BaseTxDrivenModuleManager, ProductionTimerDrivenModuleManager

public abstract class BaseModuleManager<M extends ModuleMetadata,T extends RuntimeModule>
extends Object
implements ModuleManager<T>

Base-class for ModuleManager implementations.

Field Summary

Fields

Modifier and Type	Field and Description
protected ModuleMetadataRepository	metadataRepository
protected Map<String,T>	modules

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BaseModuleManager(ModuleMetadataRepository metadataRepository, StatsCollector statsCollector) Construct a new manager.

Method Summary

Modifier and Type	Method and Description
protected abstract M	acknowledgeMetadata(T module, M metadata) Acknowledge module metadata after it has been created afresh or successfully loaded from a ModuleMetadataRepository.
void	checkNotAlreadyRegistered(RuntimeModule module) Check that the given module isn't already registered with the manager.
void	cleanupMetadata(Set<String> usedModules) Perform cleanup metadata written by modules that are no longer present.
protected abstract M	createFreshMetadata(T module) Create new metadata for a module.
<M extends RuntimeModule> M	getModule(Class<M> clazz) Get a module registered with the manager.
<M extends RuntimeModule> M	getModule(String moduleId, Class<M> clazz) Get a module registered with the manager.
protected void	handleCorruptMetadata(T module) Handle the fact that metadata for a module has been corrupted.
protected void	handleNoMetadata(T module) Handle the fact that there was no metadata for a module.
Set<String>	loadMetadata() Load module metadata from wherever they are stored in between database restarts and do whatever is necessary to do with this metadata before the modules can be used.
void	registerModule(T module) Register a module with this manager.
void	shutdownModules() Bring all modules to an orderly shutdown, when the database is stopped.
void	startModules() Perform work needed to make modules start doing their job.

Methods inherited from class java.lang.Object

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

Field Detail

modules

protected final Map<String,T extends RuntimeModule> modules

metadataRepository

protected final ModuleMetadataRepository metadataRepository

Constructor Detail

BaseModuleManager

protected BaseModuleManager(ModuleMetadataRepository metadataRepository,
                            StatsCollector statsCollector)

Construct a new manager.

Parameters:

metadataRepository - repository for storing module metadata.

Method Detail

registerModule

public final void registerModule(T module)

Register a module with this manager.

Specified by:

registerModule in interface ModuleManager<T extends RuntimeModule>

Parameters:

module - to register.

getModule

public <M extends RuntimeModule> M getModule(String moduleId,
                                             Class<M> clazz)

Get a module registered with the manager.

Specified by:

getModule in interface ModuleManager<T extends RuntimeModule>

Type Parameters:

M - type of the class above.

Parameters:

moduleId - module ID.

clazz - expected class of the module.

Returns:

module, null if no such module exists.

getModule

public <M extends RuntimeModule> M getModule(Class<M> clazz)

Get a module registered with the manager.

Specified by:

getModule in interface ModuleManager<T extends RuntimeModule>

Type Parameters:

M - type of the class above.

Parameters:

clazz - class of the module.

Returns:

module. null if no such module exists.

checkNotAlreadyRegistered

public void checkNotAlreadyRegistered(RuntimeModule module)

Check that the given module isn't already registered with the manager.

Specified by:

checkNotAlreadyRegistered in interface ModuleManager<T extends RuntimeModule>

Parameters:

module - to check.

Throws:

IllegalStateException - in case the module is already registered.

loadMetadata

public final Set<String> loadMetadata()

Load module metadata from wherever they are stored in between database restarts and do whatever is necessary to do with this metadata before the modules can be used.

Specified by:

loadMetadata in interface ModuleManager<T extends RuntimeModule>

Returns:

IDs of all modules registered with this manager.

handleCorruptMetadata

protected void handleCorruptMetadata(T module)

Handle the fact that metadata for a module has been corrupted. This could be because somebody has manually messed with the storage of module metadata, or because the implementation of the module metadata has changed and the class expected is different from the class previously serialized.

After this method has returned, it is guaranteed that createFreshMetadata(com.graphaware.runtime.module.RuntimeModule) will be called. This means that if the module doesn't heavily rely on its metadata, there is no need to override this method.

Parameters:

module - that had corrupted metadata.

handleNoMetadata

protected void handleNoMetadata(T module)

Handle the fact that there was no metadata for a module. This could be because it has been registered for the first time, or because somebody as manually deleted the metadata from wherever ModuleMetadataRepository stores them.

After this method has returned, it is guaranteed that createFreshMetadata(com.graphaware.runtime.module.RuntimeModule) will be called. This means that there is no need to override this method unless there is some work that needs to be done in addition to creating new metadata.

Parameters:

module - that had no metadata.

createFreshMetadata

protected abstract M createFreshMetadata(T module)

Create new metadata for a module.

Parameters:

module - for which to create metadata.

Returns:

fresh metadata.

acknowledgeMetadata

protected abstract M acknowledgeMetadata(T module,
                                         M metadata)

Acknowledge module metadata after it has been created afresh or successfully loaded from a ModuleMetadataRepository. The implementation can, for example, choose to let the module know about its own metadata. This method also gives the subclasses the opportunity to modify the metadata before it is persisted to the database.

Parameters:

module - for which to acknowledge metadata.

metadata - to acknowledge.

Returns:

the acknowledged metadata (possibly modified).

cleanupMetadata

public void cleanupMetadata(Set<String> usedModules)

Perform cleanup metadata written by modules that are no longer present.

Specified by:

cleanupMetadata in interface ModuleManager<T extends RuntimeModule>

Parameters:

usedModules - IDs of all modules that are known to be used by the runtime during the current run.

startModules

public void startModules()

Perform work needed to make modules start doing their job. Called exactly once each time the database is started.

Specified by:

startModules in interface ModuleManager<T extends RuntimeModule>

shutdownModules

public void shutdownModules()

Bring all modules to an orderly shutdown, when the database is stopped.

Specified by:

shutdownModules in interface ModuleManager<T extends RuntimeModule>