Some models multithreading problem

1. A multi-threaded example:

Description: a train ticketing system, there are multiple windows, but only vote there in the same system:

Design ideas: there is only one system:

                       Details Design: single design pattern to ensure that a common multi-window object

                       Use Vector collection framework to ensure the safety of concurrent threads;

                  A plurality of ticket windows, use multiple threads simulate multiple windows, the method calls the run sellTicket () method of class System employed in combination.

code show as below:

// Ticket entity class 

public  class Ticket {
     // start station, the end price
     // only some attributes of an object contains many properties, enhance readability
     // the JavaBean, POJOs 
    String Start; 
    String End; 
    the Float. Price;   // caps, packaging 

    public Ticket (String Start, End String, the Float. price) {
         the this .start = Start;
         the this .end = End;
         the this .price = . price; 
    } 

    public Ticket () { 
    } 

    public String getStart () {
         return Start ; 
    }

    public String getEnd() {
        return end;
    }

    public Float getPrice() {
        return price;
    }

    public void setStart(String start) {
        this.start = start;
    }

    public void setEnd(String end) {
        this.end = end;
    }

    public void setPrice(Float price) {
        this.price = price;
    }

    //重写toString 方法，为了打印对象方便
    public String toString(){
        StringBuilder sb=new new the StringBuilder (); 
        sb.append ( the this . .start) .append ( "->") the append ( the this .end) .append ( "Price") .append ( the this .price);
         return  new new String (SB); 
    } 
} 



// SystemTest class 

public  class SystemTest { 

    // only one system: design singleton 
    Private SystemTest () { 

    } 

    Private  static SystemTest ST = new new SystemTest ();
     // static: guarantee uniqueness 

    public  static   SystemTest the getInstance () {
         // static methods: you can call by class name 
        returnST; 
    } 

    // attribute, set the ArrayList, the Vector -> the synchronized, Stack 
     Private the Vector <Ticket> = tickets new new the Vector <> (); 

    // the current system to create, assign a set of tickets, with complete block 
    {
         for ( int 10 = I; I <100; I ++ ) { 
            tickets.add ( new new Ticket ( "Beijing" + i, "Shenzhen" I +, I +. 5%. 5 + 25F is)); 
        } 
    } 

    // design a method, from a set of take the ticket 
    public ticket getTicket () { 

        the try {
           return   tickets.remove (0 ); 
        } the catch (Exception E) {
            return null ;
                // no vote situation 
        } 

    } 
} 


// Window Windows-based 

public  class the Window the extends the Thread { 
    String windowName; 

    public the Window (String windowName) {
         the this .windowName = windowName; 
    } 

    @Override 
    public  void RUN () {
         // Sell votes 
        sellTicket (); 
    } 
    public  void sellTicket () {
         the while ( to true ) { 
            SystemTest ST =SystemTest.getInstance ();
             // get singletons 

            Ticket T = st.getTicket ();
             // obtaining tickets from the collection Vector 

            IF (T == null ) { 
                System.out.println (windowName + "window ticket has been sold End " );
                 BREAK ; 
            } 
            System.out.println (windowName +" sold: "+ T); 
        } 
    } 
} 


// the testMain test main class 

public  class the testMain {
     public  static  void main (String [] args) {
         // there are a number of windows, each of a total system
        W1 = Window new new Window ( "Beijing Railway Station" ); 
        Window W2 = new new Window ( "Xi'an station" ); 
        Window W3 = new new Window ( "Chongqing Station" ); 

        w1.start (); 
        w2.start (); 
        W3. Start (); 


    } 
}

 

 

2. turns print ABCABCABC ....... 10 times:

Locked to the subject using synchronized manner, so that each thread object access methods can not be performed simultaneously, one by one to obtain.

具体：synchronized(Object){   }

// class Test class that is is to perform printing 

// turns lock 

// thread class is a thread running up 
public  class Test the implements Runnable { 

    Private String name;    // EG: "A" 
    Private Object pre;     // OA, ob, oc circulated between before and after the three objects 
    Private Object Self;    // own 

    public the Test (String name, pre Object, Object Self) {
         the this .name = name;
         the this .PRE = pre;
         the this .self = Self; 
    } 


    / / each thread has run method of each thread. 
    @Override
    public  void RUN () {
         int count = 10;   // count down 10 times to print 
        the while (count> 0 ) {
             the synchronized (pre) {
                 the synchronized (Self) { 
                    of System.out.print (name);    // block lock 
                    count - ; 

                    self.notify (); 
                } 
                the try { 
                    pre.wait (); 
                } the catch (InterruptedException E) { 
                    e.printStackTrace (); 
                } 
            } 
 
        }
    }



 //     @Override
 //     public void RUN () {
 //         the synchronized (pre) {
 //             the synchronized (Self) {   // here is locked while the loop
 //                 // first write logic itself locked in consideration problems
 //                 int COUNT = 10;
 //                 the while (COUNT> 0) {
 //                     System.out.println (name + COUNT);
 //                     count--;
 //                     self.notify ();
 //                 }
 //             }
 //             the try {
 //                 pre.wait ();
 //            } catch (InterruptedException e) {
//                e.printStackTrace();
//            }
//        }
//    }
}


//测试主类：


public class Main {


    public static void main(String[] args) throws InterruptedException {
        Object oa=new Object();
        Object ob=new Object();
        Object oc=new Object();

        new Thread(new Test("A",oc,oa)).start();
        Thread.sleep(1000);

        new Thread(new Test("B",oa,ob)).start();
        Thread.sleep(1000);

        new Thread(new Test("C",ob,oc)).start();
        Thread.sleep(1000);
    }

}

 

 

3. Analog philosopher eating problems:

 

 

 

 

 

page