Elevator dispatching (pairing project) ②

One 、UML chart

Two 、Design by Contract, Code Contract

Design by contract （Design by Contract ,DbC） It's a way of designing computer software , It is to make an agreement on some data according to some regulations . If beyond the agreement , The program will no longer run . for example , The input parameters must meet certain conditions . Standing on the java From the perspective of language , The so-called contractual programming is when certain conditions are met , Only conditional execution method body , have access to AOP Realization Java Design by contract . stay java Of Junit We use assertions in our tests (assert) Look at our program structure .

3、 ... and 、 Realization Bus Scheduling algorithm

Bus The idea of scheduling algorithm is ： Use the elevator as a bus , from -1 From the first floor to the highest floor , Stop at every floor , And open the door to let passengers in and out , Then close the door and walk up . Up to the top , Down again .
In the process of implementation , We use four threads to run four elevators . In each thread , First, judge whether the elevator serves on this floor . If you can provide services , Then the elevator opens , At the same time call EleController Class synchronized Method GetPsgIn(), Pick up the passengers who can enter the elevator on this floor , This ensures that when each elevator accesses the waiting passenger list , There will be no thread conflicts bug.

public void busDispatcher(){
    
         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 
                    }
                }
            }).start();
        }
    }

Four 、 Making the main interface UI

The above figure shows the main interface of the elevator dispatcher made by our group , Passengers can be randomly generated on the left , You can also add passengers manually . We provide “Bus”“SSTF”“LOOK” Three buttons , For users to choose the appropriate scheduling algorithm . On the right is the simulation of elevator operation , Visually display the current floor of the elevator 、 manned 、 Load and passenger information .

“ Set elevator parameters ” Button to connect to a new interface , The service floor of the elevator can be adjusted according to the needs of users 、 Maximum manned capacity 、 Maximum load and other parameters . Enter the elevator number and fill in the new load 、 The number of , Check the service floor , You can update the parameters of the elevator .