Readme.md

/*

Coordinator Cohorts QUERY TO COMMIT --------------------------------> VOTE YES/NO prepare/abort <------------------------------- commit/abort COMMIT/ROLLBACK --------------------------------> ACKNOWLEDGMENT commit/abort <--------------------------------
end

Two Phases :

1.Prepare and Vote Phase 2. Commit or Abort Phase

"Either All Commit Or All RollBack."

*/

client.java

// Two Phase Commit --> Client

//Two Phase Commit Protocol CLIENT

package twophase;

import java.io.*;
import java.net.*;
public class Client implements Runnable
{  
	static Socket clientSocket = null;
	static PrintStream os = null; 
	static DataInputStream is = null;
	static BufferedReader inputLine = null;
	static boolean closed = false;
	public static void main(String[] args)     
	{ 
		int port_number=1111;   
		String host="localhost"; 
		try { 
			clientSocket = new Socket(host, port_number); 
			inputLine = new BufferedReader(new InputStreamReader(System.in));
			os = new PrintStream(clientSocket.getOutputStream());     
			is = new DataInputStream(clientSocket.getInputStream()); 
		} catch (Exception e) 
		{   System.out.println("Exception occurred : "+e.getMessage()); }   
		
		
		if (clientSocket != null && os != null && is != null)   
		{
			try    
			{ 
				new Thread(new Client()).start();   
				while (!closed)    
				{  
					os.println(inputLine.readLine()); 
				} 
				os.close();    
				is.close();   
				clientSocket.close();   
			} catch (IOException e)  
			{    
				System.err.println("IOException:  " + e); 
			} 
		} 
	}     
	@SuppressWarnings("deprecation")
	public void run()     {   
		String responseLine;     
		try  
		{   
			while ((responseLine = is.readLine()) != null)
			{ 
				System.out.println("\n"+responseLine); 
				if (responseLine.equalsIgnoreCase("GLOBAL_COMMIT")==true || responseLine.equalsIgnoreCase("GLOBAL_ABORT")==true )    
				{     
					break;    
				}     
			}  
			closed=true;    
		} 
		catch (IOException e)
		{    
			System.err.println("IOException:  " + e);      
		}
	}
} //end client

server.java

// Two Phase Commit --> Server

package twophase;

import java.io.*;
import java.net.*;
import java.util.*;

public class Server {
	boolean closed = false, inputFromAll = false;
	List<ClientThread> thread;
	List<String> data;

	Server() {
		thread = new ArrayList<ClientThread>();
		data = new ArrayList<String>();
	}

	public static void main(String args[]) 
	{
		Socket clientSocket = null;
		ServerSocket serverSocket = null;
		int port_number = 1111;
		Server server = new Server();
		try 
		{
			serverSocket = new ServerSocket(port_number);
		} catch (IOException e) {
			System.out.println(e);
		}
		while (!server.closed) 
		{
			try {
					clientSocket = serverSocket.accept();
					ClientThread clientThread = new ClientThread(server, clientSocket);
					(server.thread).add(clientThread);
					System.out.println("\nNow Total clients are : " + (server.thread).size());
					(server.data).add("NOT_SENT");
					clientThread.start();
			} catch (IOException e) { }
		}
		try {
			
			serverSocket.close();
		} catch (Exception e1) { }
	}
}

class ClientThread extends Thread 
{
	DataInputStream is = null;
	String line;
	String destClient = "";
	String name;
	PrintStream os = null;
	Socket clientSocket = null;
	String clientIdentity;
	Server server;

	public ClientThread(Server server, Socket clientSocket) 
	{
		this.clientSocket = clientSocket;
		this.server = server;
	}

	@SuppressWarnings("deprecation")
	public void run() 
	{
		try {
			is = new DataInputStream(clientSocket.getInputStream());
			os = new PrintStream(clientSocket.getOutputStream());
			os.println("Enter your name.");
			name = is.readLine();
			clientIdentity = name;
			os.println("Welcome " + name + " to this 2 Phase Application.\nYou will receive a vote Request now...");
			os.println("VOTE_REQUEST\nPlease enter COMMIT or ABORT to proceed : ");
			for (int i = 0; i < (server.thread).size(); i++) 
			{
				if ((server.thread).get(i) != this) 
				{
					((server.thread).get(i)).os.println("---A new user " + name + " entered the  Appilcation---");
				}
			}
			while (true) 
			{
				line = is.readLine();
				if (line.equalsIgnoreCase("ABORT")) 
				{
					System.out.println("\nFrom '" + clientIdentity
							+ "' : ABORT\n\nSince aborted we will not wait for inputs from other clients.");
					System.out.println("\nAborted....");
					
					for (int i = 0; i < (server.thread).size(); i++) {
						((server.thread).get(i)).os.println("GLOBAL_ABORT");
						((server.thread).get(i)).os.close();
						((server.thread).get(i)).is.close();
					}
					break;
				}
				if (line.equalsIgnoreCase("COMMIT")) 
				{
					System.out.println("\nFrom '" + clientIdentity + "' : COMMIT");
					if ((server.thread).contains(this)) 
					{
						(server.data).set((server.thread).indexOf(this), "COMMIT");
						for (int j = 0; j < (server.data).size(); j++) 
						{
							if (!(((server.data).get(j)).equalsIgnoreCase("NOT_SENT"))) 
							{
								server.inputFromAll = true;
								continue;
							} 
							else{
								server.inputFromAll = false;
								System.out.println("\nWaiting for inputs from other clients.");
								break;
							}
						}
						if (server.inputFromAll) 
						{
							System.out.println("\n\nCommited....");
							for (int i = 0; i < (server.thread).size(); i++) 
							{
								((server.thread).get(i)).os.println("GLOBAL_COMMIT");
								((server.thread).get(i)).os.close();
								((server.thread).get(i)).is.close();
							}
							break;
						}
					} // if thread.contains
				} // commit
			} // while
			server.closed = true;
			clientSocket.close();
		} catch (IOException e) { }
		
	}
}// end class thread