package org.apidesign.deadlock.startuplock;

 import java.io.DataOutputStream;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.net.ServerSocket;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 public final class CLIHandlerBlocking {

     // BEGIN: cli.real

     public static int start(File lockFile) throws IOException {

         enterState(10);

         if (lockFile.exists ()) {

             // read the port number and connect to it

             enterState(11);

             int alive = readPortNumber(lockFile);

             if (alive != -1) {

                 // exit

                 return alive;

             }

         }

         // otherwise try to create the file yourself

         enterState(20);

         lockFile.createNewFile();

         DataOutputStream os = new DataOutputStream(

             new FileOutputStream(lockFile)

         );

         ServerSocket server = new ServerSocket();

         enterState(21);

         int p = server.getLocalPort();

         enterState(22);

         os.writeInt(p);

         enterState(23);

         return p;

     }

     // END: cli.real

     private static Logger LOG = Logger.getLogger(CLIHandlerBlocking.class.getName());

     private static void enterState(int state) {

         LOG.log(Level.FINEST, "enterState {0}", state);

     }

     private static int readPortNumber(File lockFile) throws IOException {

         return -1;

     }

 }