Exercise four

Synchronization of Selling Tickets at the Window

package MultiThread;

public class Main {
	public static void main(String[] args) {
        Window w = new Window();
        w.window();
    }
}

package MultiThread;

class Test  implements Runnable {
	private static int num = 1;
	int f = 0;
	
	@Override
	public void run() {
		while(true) {
			synchronized(this) {
				if(num <= 20) {
					System.out.println(Thread.currentThread().getName() + ": ticket " + num++);
					try {
	                    Thread.sleep(50);
	                } catch (InterruptedException e) {
	                    e.printStackTrace();
	                }
				}
				else {
					if(f == 0) {
						System.out.println("Sold Out");
						f = 1;
					}
					return;
				}
			}
		}
	}
	
}


public class Window {
	void window() {
		Test tr = new Test();
		Thread t1 = new Thread(tr, "Window 1");
        Thread t2 = new Thread(tr, "Window 2");
        Thread t3 = new Thread(tr, "Window 3");
        t1.start();
        t2.start();
        t3.start();
	}
}

Inter-Thread Synchronization

package MultiThread1;

class Test  implements Runnable {
	private static int aaa = 100;
	private static int bbb = 0;
	private static int ccc = 0;
	
	@Override
	public void run() {
		while(true) {
			synchronized(this) {
				if((Thread.currentThread().getName().equals("B") && bbb < 1000)||(Thread.currentThread().getName().equals("C") && ccc < 1000)) {
					aaa += 100;
					System.out.println("account "+Thread.currentThread().getName()+" transfer $100 to account A, balance of account A: $" + aaa);
					
					if(Thread.currentThread().getName().equals("B")) bbb+=100;
					else ccc+=100;
					
					try {
	                    Thread.sleep(50);
	                } catch (InterruptedException e) {
	                    e.printStackTrace();
	                }
				}
				else {
					if(bbb >= 1000 && ccc >= 1000){
						System.out.println("account B transfer $1000 to account A in total");
						System.out.println("account C transfer $1000 to account A in total");
						System.out.println("balance of account A: $2100");
					}
					return;
				}
			}
		}
	}
	
}

public class Bank {
	void bank(){
		System.out.println("balance of account A: $100");
		Test tr = new Test();
		Thread t1 = new Thread(tr, "B");
        Thread t2 = new Thread(tr, "C");
        t1.start();
        t2.start();
	}
}

package MultiThread1;

public class Main {
    public static void main(String[] args) {
        Bank b = new Bank();
        b.bank();
    }
}

Deadlock: Dining Philosopher Problem

package MultiThread2;

public class Customer extends Thread {
	Text text;

	Customer(Text text) {
	   this.text = text;
	}
	
	@Override
    public void run() {
		int i = 1;
	    while(true) {
	       text.Get(i++);
	       if(i > 10) return;
	    }
    }
}

package MultiThread2;

class Text {
	int count = 0;
	
	synchronized void Set(int num) {
		while(count == 1) {
			try {
				wait();
			} catch (InterruptedException ie) {
				ie.printStackTrace();
				System.exit(0);
			}
		}
		int f = num % 2;
		if(f == 1) {
			System.out.println("Set "+ num +"-> Item1 : 12345");
		}else if(f == 0) {
			System.out.println("Set "+ num +"-> Item2 : abcde");
		}
		count = 1;
		notifyAll();
	}
	
	synchronized void Get(int num) {
		while(count == 0) {
			try {
				wait();
			} catch (InterruptedException ie) {
				ie.printStackTrace();
				System.exit(0);
			}
		}
		int f = num % 2;
		if(f == 1) {
			System.out.println("Get "+ num +"-> Item1 : 12345");
		}else if(f == 0) {
			System.out.println("Get "+ num +"-> Item2 : abcde");
		}
		count = 0;
		notifyAll();
	}
}


public class Master {
	void master(){
		Text text = new Text();
	    new Producer(text).start();
	    new Customer(text).start();
	}
}

package MultiThread2;

public class Producer extends Thread {
	Text text;

	Producer(Text text) {
	   this.text = text;
	}
	
	@Override
    public void run() {
		int i = 1;
	    while(true) {
	       text.Set(i++);
	       if(i > 10) return;
	    }
    }
}

package MultiThread2;

public class Main {
	public static void main(String[] args){
        Master m = new Master();
        m.master();
    }
}

Deadlock: Dining Philosopher Problem

package Deadlock;

class MEN extends Thread{
    private String name;
    private Fork cur;
    public MEN(String name,Fork cur){
        super(name);
        this.name=name;
        this.cur=cur;
    }
    
    public void run(){
        while(true){
            thinking();
            cur.tryTodo();
            eating();
            cur.OverDo();
        }
    }
    
    public void eating(){
        System.out.println(name + " is eating.");
        try {
            sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    
    public void thinking(){
        System.out.println(name + " is thinking.");
        try {
            sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

class Fork{
    private boolean[] flag = {false,false,false,false,false,false};
    
    public synchronized void tryTodo(){
        int i = Thread.currentThread().getName().charAt(3)-'0';
        int a = i, b = i+1; 
        if(b == 6) b = 1;
        while(flag[a]||flag[b]){
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        flag[a]=true;  flag[b]=true;
    }
    
    public synchronized void OverDo(){
        int i = Thread.currentThread().getName().charAt(3)-'0';
        int a = i, b = i+1; 
        if(b == 6) b = 1;
        flag[a]=false;  flag[b]=false;
        System.out.println(Thread.currentThread().getName() + " is over eating.");
        notifyAll();
    }
}


public class Deadlock {
    public static void main(String []args){
        Fork cur = new Fork();
        // 1 2 3 4 5 -> 1
        for(int i=1; i<=5; i++)
        	new MEN("men" + i, cur).start();
    }
}