/*
 * MThreadedJobQImpl.h
 *
 *  Created on: 2016年11月18日
 *      Author: nego
 */

#ifndef SERVICE_IMPL_MTHREADEDJOBQIMPL_H_
#define SERVICE_IMPL_MTHREADEDJOBQIMPL_H_

#include <pthread.h>
#include <vector>

class JobExecuterImpl;
class JobI;

class MThreadedJobQImpl {
public:
	typedef struct THNODE {
		//Pointer to the Job Executer
		JobExecuterImpl* pExecuter;

		//Pointer to next THNODE
		THNODE * pNext;
	} THNODE;

	//This is the pointer to the the thread (instance of CWinThread) which is
	//responsible for observing and assigning the jobs to the free executer threads.
	pthread_t pid;

	//CriticalSection object, used for synchronized access of shared resources
	//between the thread.
	//CCriticalSection m_cs;

	//This is the link list to maintain the priority queue of jobs.
	std::vector<JobI* > m_jobQList;

	//This method deletes a job executer. This method is not required to be used by the user. This is only for the use of the implementation of the multithreaded job queue.
	void deleteJobExecuter(JobExecuterImpl *pEx);

	//The setMaxNoOfExecuter method sets the maximum number of executer. If the user increases
	//the maximum number of executer then the multithreaded job queue will create more
	//threads to execute more jobs parallely. If the user decreases the max number of
	//executers then the job queue brings down the number of executer. The bringing
	//down process may not be immediate if all the executers are busy in processing.
	//In such a case the number will come down as soon as some jobs gets finished.
	void setMaxNoOfExecuter(int value);

	//This method adds a CJobExecuter to the Job executer link list. This method
	//is not required to be called by the user, this is only for the use of the
	//implementation of the multithreaded job queue
	void addJobExecuter(JobExecuterImpl *pEx);

	//This method returns a free Job Executer. This method is not required to be
	//called or used by the user. This is only for the implementation of the
	//multithreaded job queue.
	JobExecuterImpl* getJobExecuter();

	//This method adds a Job Executer to the free job executer list. This method
	//is not required to be used by the user, this is only for the use of the
	//implementation of the multithreaded job queue.
	void addFreeJobExecuter(JobExecuterImpl *pEx);

	//This method adds a job to the job queue. The job is passed as the parameter.
	void addJob(JobI *pJob);

	//This method returns the maximum number allowed executer threads.
	int getMaxNoOfExecuter();

	//This method returns the number of executer present at any instance of time.
	int getNoOfExecuter();

	//This is the static thread function. This function is not to be used by the user.
	//This function is used to create the observer thread.
	static void* JobObserverThreadFunction(void*);

	//This pauses the Multithreaded job queue, so that no new job gets processed.
	//But the user can add new jobs to the job queue. The jobs will be processed
	//when the user again resumes. But this does not pauses currently running jobs.
	void pause();

	//This resumes the Multithreaded job queue, after resume all the pending
	//jobs will be processed.
	void resume();

	void start();

	MThreadedJobQImpl();virtual ~MThreadedJobQImpl();

private:
	//The BOOL attribute to state whether the observer thread should process or
	//not the new jobs.
	bool m_pause;

	//This int attribute represent the maximum limit of the executers. At any
	//instance of time the total number of free , and busy executer threads all
	//together should not exceed this number.
	int m_MaxNoOfExecuter;

	//This int attribute is to maintain the number of executer that are present
	//at a particular instance of time to execute the Jobs.
	int m_NoOfExecuter;

	//This is the pointer to the head of the link list which maintains the free executer
	//thread list.
	THNODE* m_pFreeEList;

	//This is the head of the link list that maintains all the executer thread list.
	THNODE* m_pAllEList;

	static pthread_mutex_t xLock;
};

#endif /* SERVICE_IMPL_MTHREADEDJOBQIMPL_H_ */