Elevator dispatching (pairing project) ③

One 、SSTF Algorithm implementation

The shortest time to find a floor is preferred （SSTF-Shortest Seek Time First） The core idea of the algorithm is to find the nearest passenger for service . In order to make the elevator practical , Only look for the nearest passenger when there is no one in the elevator , And will not be interrupted . During this process, if there are new passengers waiting , Then get on the elevator , Interrupt search . When there are people in the elevator, run in the original direction , Until the last passenger gets off the elevator .

When the elevator reaches the floor, there are passengers waiting , The direction of passengers going upstairs and downstairs is consistent with the running direction of the elevator , And the current elevator can open the door when it reaches the passenger's target floor , Otherwise, go on 、 Downstairs . When the passenger is the highest / Passengers on the lowest floor , Open door , Get on the elevator . Do not open the door in other cases . When the elevator is empty, it will automatically detect the passengers on the highest floor and the passengers on the lowest floor , The elevator will not go lower than the building where the lowest floor passenger is located and higher than the building where the highest floor passenger is located .

SSTF The main logic of the algorithm is as follows ：

public void sstfDispatcher(){
    
         Randomly generate passengers 
         The thread used to dispatch the elevator （ common 4 individual ）
        for (int i = 0; i < ELE_COUNT; i++)
        {
    
            new Thread(()->{
    
                while (true){
    
                     Get the current status and floor 
                     Get the nearest passenger （ Including judging whether the target floor of the passenger can reach ）
                     If the elevator is empty , Change the direction of the elevator to the direction of the nearest passenger 
                    while( The nearest passenger's floor is not reached and the elevator is empty ){
    
                         If services are provided at this level 
                             Detect that no one gets on or off the elevator 
                       	 Go ahead / Downstairs 
                    }
                     Determine whether to serve on this layer 
                    	 Check whether there is getting on and off the elevator 
                     The elevator runs 
                    }
                }
            }).start();
        }
    }

among , Find the nearest passenger to use EleController Class getNearestPsg() function , This function can find the nearest passenger who can reach the target floor .

Passengers entering and leaving the elevator are also encapsulated into a function psgOnOrOff(), First detect whether there are passengers on the floor , Whether the target floor of passengers can reach , And whether the passenger's target direction is consistent with the current elevator running direction , If all is satisfied , Then open the door , Passengers get on or off the elevator . The realization and of passengers getting on and off the elevator bus Same algorithm .

There are two kinds of elevator operation , One is eleRun(), The other is eleSmartRun().eleSmartRun() Only used when the elevator is empty ： If there are no customers waiting , The elevator stops sleeping for a certain time ; If the current floor goes up and does not reach the highest floor that can be reached and the floor where the passengers are on the highest floor , Then continue to go up , On the contrary, it goes down . Another kind eleRun() Keep running in the original direction , Until you reach the highest accessible floor or the last passenger gets off the elevator .

Two 、LOOK Algorithm

In the realization of SSTF In fact, when calculating the algorithm, I just put LOOK The algorithm is implemented , however SSTF The algorithm is not necessarily better than LOOK Practical algorithm .

LOOK The idea of the algorithm is to change the running direction immediately when there is no request in the moving direction of the elevator . On the implementation , Put the above SSTF The part of finding the nearest passenger in the algorithm is removed , Namely LOOK The algorithm . Mainly by eleSmartRun() Realization . The specific implementation function is the same as SSTF Algorithm .

public void lookDispatcher(){
    
         Randomly generate passengers 
         The thread used to dispatch the elevator （ common 4 individual ）
        for (int i = 0; i < ELE_COUNT; i++)
        {
    
            new Thread(()->{
    
                while (true){
    
                     Get the current status and floor 
                     Determine whether to serve on this layer 
                    	 Check whether there is getting on and off the elevator 
                     The elevator runs （ Here, judge whether there is a request in the moving direction of the elevator ）
                    }
                }
            }).start();
        }
    }

3、 ... and 、 Algorithm and UI Interface connection

ui The interface uses javafx, There are three interfaces ：

Start

The function of this interface is to open multiple elevator controller windows at the same time , This is the main window . Click the button in the middle to open a new elevator controller window , Each window is independent .

MainWindow

This interface is the main interface , Passengers can be added manually on the upper left , from onAddCosButtonClicked() Realization .

Then press the next Bus,SSTF,LOOK Button to execute the corresponding algorithm . Due to time , Algorithm switching and pause are not implemented .

Then left ” Number of people waiting “,” Number of people served “, And below ” The total number of “ Corresponding to the current number of people waiting to get on the elevator , Number of people served , And the total number of people from the beginning to the operation .” Number of people served / The total number of “ It is an evaluation index of elevator operation efficiency , The initial value is 1, from refreshTotalInfo() Method realization .

White on the left TextArea It is used to display the information of all passengers , from refreshHisCosInfoArea Realization .

The situation of the four elevators on the right is explained from top to bottom ：

​ The upper part shows the current arrival floor of the elevator in real time , from changeFloor() Method realization .

​ The middle number and the remaining weight can be accommodated by setEleInfo() Method realization .

​ Next, update the information of passengers who have boarded the elevator by refreshEleArea() Method realization .

Click the set elevator parameters button on the far right to pop up a new window , To change elevator parameters , As follows .

SetElePara

After filling in the elevator parameters, click Modify Parameters to modify the parameters of a specific elevator . from onSetButtonClicked() Method realization .