Untitled

package jbdc;

import com.mongodb.*;
import java.util.Scanner;

public class jdbc 
{

	static MongoClient mongo = new MongoClient("10.10.12.108", 27017);
	static DB db = mongo.getDB("t31ds");
	static DBCollection col = db.getCollection("students");
	static Scanner s = new Scanner(System.in);
	
	public static void insertR(int rec, BasicDBObject d[])
	{
		int rn, marks;
		String name;
		System.out.println("Please enter the following information.");
		for(int i = 0; i < rec; i++)
		{
			System.out.println("Roll No.: ");
			rn = s.nextInt();
			System.out.println("Name: ");
			name = s.next();
			System.out.println("Marks: ");
			marks = s.nextInt();
			d[i] = new BasicDBObject("roll", rn).append("name", name).append("marks", marks);
			col.insert(d[i]);
		}
	}
	
	public static void updateR(int rn, String name, int marks, BasicDBObject d[])
	{	
		System.out.println(rn+name+marks);
		int val = rn % 10;
		BasicDBObject dnew = new BasicDBObject("roll", rn).append("name", name).append("marks", marks);
		BasicDBObject dup = new BasicDBObject("$set", dnew);
		col.update(d[val-1], dup);
		
		System.out.println("Updated");
	}
	
	public static void displayC()
	{
		DBCursor cursor = col.find();
		while(cursor.hasNext())
		{
			System.out.println(cursor.next());
		}
	}
	
	public static void deleteR(int rn, BasicDBObject d[])
	{
		int val = rn % 10;
		col.remove(d[val-1]);
	}
	public static void main(String[] args) 
	{
		BasicDBObject d[] = new BasicDBObject[20];
		int op = 0;
		while(op != 5)
		{
			System.out.println("\nS.NO.\tOPTION");
			System.out.println("  1. \tInsert Records");
			System.out.println("  2. \tUpdate Record");
			System.out.println("  3. \tDisplay Collection");
			System.out.println("  4. \tDelete Record");
			System.out.println("  5. \tExit");
			System.out.println("\nPlease enter an option: ");
			op = s.nextInt();
			switch(op)
			{
			case 1:
				System.out.println("Option 1: Insert Records");
				int rec;
				System.out.println("Please enter the number of records you would like to insert.\nRecords: ");
				rec = s.nextInt();
				insertR(rec, d);
				break;
			case 2:
				System.out.println("Option 2: Update Record");
				System.out.println("Please enter the following information.");
				int rn, marks;
				String name;
				System.out.println("Roll No.: ");
				rn = s.nextInt();
				System.out.println("Name: ");
				name = s.next();
				System.out.println("Marks: ");
				marks = s.nextInt();
				updateR(rn, name, marks, d);
				break;
			case 3:
				System.out.println("Option 3: Display Collection");
				displayC();
				break;
			case 4:
				System.out.println("Option 4: Delete Record");
				System.out.println("Please enter the roll number of the record you want to delete from collection.\nRoll No.: ");
				int roll = s.nextInt();
				deleteR(roll, d);
				break;
			case 5:
				System.out.println("Option 5: Exit");
				System.out.println("Exiting...");
				System.exit(0);
				break;
			default:
				System.out.println("Invalid Option");
				break;
			}
		}
	}
}