TMPWorkerExecutor< F, T, R > Class Template Reference

template<class F, class T = void, class R = void>
class TMPWorkerExecutor< F, T, R >

This class works together with TProcessExecutor to allow the execution of functions in server processes.

Depending on the exact task that the worker is required to execute, a different version of the class can be called.

TMPWorkerExecutor<F, T, R>

The most general case, used by TProcessExecutor::MapReduce(F func, T& args, R redfunc). This worker is build with:

• a function of signature F (the one to be executed)
• a collection of arguments of type T on which to apply the function
• a reduce function with signature R to be used to squash many returned values together.

Partial specializations

A few partial specializations are provided for less general cases:

• TMPWorkerExecutor<F, T, void> handles the case of a function that takes one argument and does not perform reduce operations (TProcessExecutor::Map(F func, T& args)).
• TMPWorkerExecutor<F, void, R> handles the case of a function that takes no arguments, to be executed a specified amount of times, which returned values are squashed together (reduced) (TProcessExecutor::Map(F func, unsigned nTimes, R redfunc))
• TMPWorkerExecutor<F, void, void> handles the case of a function that takes no arguments and whose arguments are not "reduced" (TProcessExecutor::Map(F func, unsigned nTimes))

Since all the important data are passed to TMPWorkerExecutor at construction time, the kind of messages that client and workers have to exchange are usually very simple.

Definition at line 77 of file TMPWorkerExecutor.h.

Public Member Functions
	TMPWorkerExecutor (F func, const std::vector< T > &args, R redfunc)
	~TMPWorkerExecutor ()
void	HandleInput (MPCodeBufPair &msg)
	Handle a message with an EMPCode.
Public Member Functions inherited from TMPWorker
	TMPWorker ()
	TMPWorker (const TMPWorker &)=delete
	TMPWorker (unsigned nWorkers, ULong64_t maxEntries)
virtual	~TMPWorker ()
unsigned	GetNWorker () const
pid_t	GetPid ()
TSocket *	GetSocket ()
virtual void	Init (int fd, unsigned workerN)
	This method is called by children processes right after forking.
TMPWorker &	operator= (const TMPWorker &)=delete
void	Run ()

Private Attributes
std::vector< T >	fArgs
	a vector containing the arguments that must be passed to fFunc
bool	fCanReduce
	true if fReducedResult can be reduced with a new result, false until we have produced one result
F	fFunc
	the function to be executed
R	fRedFunc
	the reduce function
decltype(fFunc(fArgs.front()))	fReducedResult
	the result of the execution

Additional Inherited Members
Protected Member Functions inherited from TMPWorker
void	SendError (const std::string &errmsg, unsigned int code=MPCode::kError)
	Error sender.
Protected Attributes inherited from TMPWorker
std::string	fId
	identifier string in the form W<nwrk>|P<proc id>
ULong64_t	fMaxNEntries
	the maximum number of entries to be processed by this worker
unsigned	fNWorkers
	the number of workers spawned
ULong64_t	fProcessedEntries
	the number of entries processed by this worker so far

#include <TMPWorkerExecutor.h>

Inheritance diagram for TMPWorkerExecutor< F, T, R >:

Constructor & Destructor Documentation

TMPWorkerExecutor()

template<class F , class T = void, class R = void>

TMPWorkerExecutor< F, T, R >::TMPWorkerExecutor ( F  func, const std::vector< T > &  args, R  redfunc  )

inline

Definition at line 82 of file TMPWorkerExecutor.h.

~TMPWorkerExecutor()

template<class F , class T = void, class R = void>

TMPWorkerExecutor< F, T, R >::~TMPWorkerExecutor ( )

inline

Definition at line 86 of file TMPWorkerExecutor.h.

Member Function Documentation

HandleInput()

template<class F , class T = void, class R = void>

void TMPWorkerExecutor< F, T, R >::HandleInput ( MPCodeBufPair &  msg )

inlinevirtual

Handle a message with an EMPCode.

This method is called upon receiving a message with a code >= 1000 (i.e. EMPCode). It handles the most generic types of messages.
Classes inheriting from TMPWorker should implement their own HandleInput function, that should be able to handle codes specific to that application.
The appropriate version of the HandleInput method (TMPWorker's or the overriding version) is automatically called depending on the message code.

Reimplemented from TMPWorker.

Definition at line 88 of file TMPWorkerExecutor.h.

Member Data Documentation

fArgs

template<class F , class T = void, class R = void>

std::vector<T> TMPWorkerExecutor< F, T, R >::fArgs

private

a vector containing the arguments that must be passed to fFunc

Definition at line 119 of file TMPWorkerExecutor.h.

fCanReduce

template<class F , class T = void, class R = void>

bool TMPWorkerExecutor< F, T, R >::fCanReduce

private

true if fReducedResult can be reduced with a new result, false until we have produced one result

Definition at line 122 of file TMPWorkerExecutor.h.

fFunc

template<class F , class T = void, class R = void>

F TMPWorkerExecutor< F, T, R >::fFunc

private

the function to be executed

Definition at line 118 of file TMPWorkerExecutor.h.

fRedFunc

template<class F , class T = void, class R = void>

R TMPWorkerExecutor< F, T, R >::fRedFunc

private

the reduce function

Definition at line 120 of file TMPWorkerExecutor.h.

fReducedResult

template<class F , class T = void, class R = void>

decltype(fFunc(fArgs.front())) TMPWorkerExecutor< F, T, R >::fReducedResult

private

the result of the execution

Definition at line 121 of file TMPWorkerExecutor.h.