fire::ConditionsProvider Class Reference

Base class for all providers of conditions objects. More...

#include <ConditionsProvider.h>

Inheritance diagram for fire::ConditionsProvider:

Collaboration diagram for fire::ConditionsProvider:

Public Types
using	Factory = factory::Factory< ConditionsProvider, std::shared_ptr< ConditionsProvider >, const config::Parameters & >
	The factory type that can create this class. More...

Public Member Functions
	ConditionsProvider (const fire::config::Parameters &ps)
	Configure the registered provider. More...
virtual	~ConditionsProvider ()=default
	default destructor, virtual so derived types can be destructed
virtual std::pair< const ConditionsObject *, ConditionsIntervalOfValidity >	getCondition (const EventHeader &context)=0
	Pure virtual getCondition function. More...
virtual void	release (const ConditionsObject *co)
	Called by conditions system when done with a conditions object, appropriate point for cleanup. More...
virtual void	onProcessStart ()
	Callback for the ConditionsProvider to take any necessary action when the processing of events starts.
virtual void	onProcessEnd ()
	Callback for the ConditionsProvider to take any necessary action when the processing of events finishes, such as closing database connections.
virtual void	onNewRun (RunHeader &)
	Callback for the ConditionsProvider to take any necessary action when the processing of events starts for a given run. More...
const std::string &	getConditionObjectName () const
	Get the condition object available from this provider.
const std::string &	getTagName () const
	Access the tag name.
virtual void	attach (Conditions *c) final
	Attach the central conditions system to this provider.

Protected Member Functions
std::pair< const ConditionsObject *, ConditionsIntervalOfValidity >	requestParentCondition (const std::string &name, const EventHeader &context)
	Request another condition needed to construct this condition. More...

Protected Attributes
logging::logger	theLog_
	The logger for this ConditionsProvider.

Private Attributes
Conditions *	conditions_ {nullptr}
	Handle to the central conditions system.
std::string	objectName_
	The name of the object provided by this provider.
std::string	tagname_
	The tag name for the ConditionsProvider.

Detailed Description

Base class for all providers of conditions objects.

Besides defining the necessary virtual callbacks, we also provide the factory infrastructure for dynamically creating providers from loaded libraries and we define a requestParentCondition function that can be used by other providers to obtain conditions other conditions depend on.

Usage

Defining a conditions provider is done similarly to a Processor. Since ConditionsProviders are generally only used after some experience with Processors is obtained, I will not go into as much detail. Perhaps the best way is to provide an example from which you can learn.

// MyConditionsProvider.cpp
#include <fire/ConditionsProvider.h>
class MyConditionsProvider : public fire::ConditionsProvider {
 public:
  MyConditionsProvider(const fire::config::Parameters& p)
    : fire::ConditionsProvider(p) {
    // deduce configuration of provider from parameter set p
  }
  ~MyConditionsProvider() = default;
  virtual std::pair<const ConditionsObject*, ConditionsIntervalOfValidity>
  getCondition(const EventHeader& context) final override {
    // use context to determine correct configuration of conditions object
    // as well as the range of run numbers and type of data that the
    // condition is valid for
  }
};
DECLARE_CONDITIONS_PROVIDER(MyConditionsProvider);

One special (but somewhat common) use case is a global condition that is light in memory. These criteria are satisifed by the RandomNumberSeedService and allow the conditions provider and the conditions object to be the same object.

// LightAndGlobalCondition.cpp
#include <fire/ConditionsProvider.h>
class LightAndGlobalCondition : public fire::ConditionsProvider, 
                                       fire::ConditionsObject {
 public:
  LightAndGlobalCondition(const fire::config::Parameters& p)
    : fire::ConditionsProvider(p) {
    // deduce configuration of both provider and object from parameter set p
  }
  ~LightAndGlobalCondition() = default;
  // return ourselves and infinite validity
  virtual std::pair<const ConditionsObject*, ConditionsIntervalOfValidity>
  getCondition(const EventHeader& context) final override {
    return std::make_pair(this, ConditionsIntervalOfValidity(true,true)); 
  }
  // don't allow conditions system to delete us
  virtual void release(const ConditionsObject* co) final override {}
};
DECLARE_CONDITIONS_PROVIDER(LightAndGlobalCondition);

One could also image a light condition which may still change with the context, but that can be implemented from this example.

Member Typedef Documentation

Factory

using fire::ConditionsProvider::Factory = factory::Factory<ConditionsProvider, std::shared_ptr<ConditionsProvider>, const config::Parameters&>

The factory type that can create this class.

We provide the class type, the type of pointer for this class, and the arguments to the constructor.

Constructor & Destructor Documentation

ConditionsProvider()

fire::ConditionsProvider::ConditionsProvider

(

const fire::config::Parameters &

ps

)

Configure the registered provider.

Parameters

[in]

ps

Parameters to configure the provider

Member Function Documentation

getCondition()

virtual std::pair< const ConditionsObject *, ConditionsIntervalOfValidity > fire::ConditionsProvider::getCondition ( const EventHeader &  context )

pure virtual

Pure virtual getCondition function.

Must be implemented by any Conditions providers.

Parameters

[in]

context

EventHeader for the condition

Returns

pair of condition and its interval of validity

Implemented in fire::RandomNumberSeedService.

onNewRun()

virtual void fire::ConditionsProvider::onNewRun ( RunHeader &  )

inlinevirtual

Callback for the ConditionsProvider to take any necessary action when the processing of events starts for a given run.

Reimplemented in fire::RandomNumberSeedService.

release()

virtual void fire::ConditionsProvider::release ( const ConditionsObject *  co )

inlinevirtual

Called by conditions system when done with a conditions object, appropriate point for cleanup.

Note

Default behavior is to delete the object!

Parameters

[in]

co

condition to cleanup

Reimplemented in fire::RandomNumberSeedService.

requestParentCondition()

std::pair< const ConditionsObject *, ConditionsIntervalOfValidity > fire::ConditionsProvider::requestParentCondition ( const std::string &  name, const EventHeader &  context  )

protected

Request another condition needed to construct this condition.

This is where we use the handle to the central conditions system and this allows us to recursively depend on other instances ConditionsProvider.

Parameters

[in]	name	condition name that is needed
[in]	context	EventHeader for which to get condition

Returns

pair of parent condition and its interval of validity

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The documentation for this class was generated from the following files:

• include/fire/ConditionsProvider.h
• src/fire/ConditionsProvider.cxx