dinningphilosopher.DinningPhilosopher.java Source code

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Here is the source code for dinningphilosopher.DinningPhilosopher.java

Source

/*
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package dinningphilosopher;

import java.net.UnknownHostException;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import com.mongodb.*;

/**
 *
 * @author Abhz
 */
public class DinningPhilosopher extends Mongo {
    public DinningPhilosopher() throws UnknownHostException {
        super();
        // TODO Auto-generated constructor stub
    }

    public static void main(String[] args) {
        Lock forks[] = new ReentrantLock[5];
        try {

            MongoClient mongoClient = new MongoClient("localhost");
            System.out.println("Connection to mongodb successful.");
            DB db = mongoClient.getDB("mydb");
            System.out.println("Database 'mydb' created.");
            DBCollection coll = db.createCollection("mycol", null);
            System.out.println("Collection 'mycol' created.");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        for (int i = 0; i < 5; i++) {
            forks[i] = new ReentrantLock();
        }
        Thread p1 = new Thread(new Philosopher(forks[4], forks[0], "first"));
        Thread p2 = new Thread(new Philosopher(forks[0], forks[1], "second"));
        Thread p3 = new Thread(new Philosopher(forks[1], forks[2], "third"));
        Thread p4 = new Thread(new Philosopher(forks[2], forks[3], "fourth"));
        Thread p5 = new Thread(new Philosopher(forks[3], forks[4], "fifth"));
        p1.start();
        p2.start();
        p3.start();
        p4.start();
        p5.start();
    }
}

class Philosopher implements Runnable {
    Lock leftFork = new ReentrantLock();
    Lock rightFork = new ReentrantLock();
    String name;

    public Philosopher(Lock leftFork, Lock rightFork, String name) {
        this.leftFork = leftFork;
        this.rightFork = rightFork;
        this.name = name;
    }

    @Override
    public void run() {
        try {
            think(name);
            eat(leftFork, rightFork, name);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private void eat(Lock leftFork, Lock rightFork, String name) throws Exception {
        leftFork.lock();
        rightFork.lock();
        try {
            MongoClient mongoClient = new MongoClient("localhost");
            DB db = mongoClient.getDB("mydb");
            DBCollection coll = db.getCollection("mycol");
            System.out.println(name + " eating...");
            BasicDBObject doc1 = new BasicDBObject(name, " eating...");
            coll.insert(doc1);
            Thread.sleep(1000);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            System.out.println(name + " done eating and now thinking...");
            MongoClient mongoClient = new MongoClient("localhost");
            DB db = mongoClient.getDB("mydb");
            DBCollection coll = db.getCollection("mycol");
            BasicDBObject doc2 = new BasicDBObject(name, " done eating and now thinking...");
            coll.insert(doc2);
            leftFork.unlock();
            rightFork.unlock();
        }
    }

    public void think(String name) throws Exception {
        try {
            MongoClient mongoClient = new MongoClient("localhost");
            DB db = mongoClient.getDB("mydb");
            DBCollection coll = db.getCollection("mycol");
            System.out.println(name + " thinking...");
            BasicDBObject doc = new BasicDBObject(name, " thinking...");
            coll.insert(doc);
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}