// Stateful Session Beans provide functionality that is a cross between
// Stateless Session Beans and Entity Beans.  While EBs are transactional
// objects, SFSBs are only transactionally aware (but only if the Bean
// implements the SessionSynchronization interface).
//
// In the first set of output below, the Bean was deployed with BMTD
// and no explicit transaction boundaries.  As a result, the Session-
// Synchronization callback methods were never invoked.  In the second
// set of output, CMTD was specified and the transaction attribute of
// Required was set on guess().  When setRollbackOnly() was invoked,
// this produced a ServerException on the client, and the
// afterCompletion() method received an argument of "false".

package demos;

import java.rmi.RemoteException;
import javax.ejb.*;
import java.util.Random;

interface RIGuessGame extends EJBObject {
  int guess( int num ) throws RemoteException;
}

interface HIGuessGame extends EJBHome {
  RIGuessGame create( int max ) throws RemoteException, CreateException;
}

public class GuessGameBean implements SessionBean, SessionSynchronization {
  private SessionContext context;
  private Random         rn = new Random();
  private int            answer, diff;

  public int guess( int num ) {
    System.out.println( "  guess: num,ans  " + num + "," + answer );
    diff = Math.abs( answer - num );
    if (num == answer) return 0;
    return (num < answer) ? -1 : 1;
  }

  public void ejbCreate( int max ) {
    answer = rn.nextInt( max ) + 1;
    System.out.println( "ejbCreate: " + answer );
  }
  public void setSessionContext( SessionContext ctx ) {
    System.out.println( "setSessionContext:" );
    context = ctx;
  }
  public void ejbRemove() {
    System.out.println( "ejbRemove: " + answer );
    answer = 0;
  }
  public void ejbActivate()  { System.out.println( "ejbActivate: " + answer ); }
  public void ejbPassivate() { System.out.println( "ejbPassivate: " + answer ); }

  // SessionSynchronization callback methods
  public void afterBegin() { System.out.println( "afterBegin: " + answer ); }
  public void beforeCompletion() {
    System.out.println( "beforeCompletion: " + answer );
    if (diff == 0) {
      System.out.println( "  ASKING FOR ROLLBACK" );
      context.setRollbackOnly();
  } }
  public void afterCompletion( boolean comp ) {
    System.out.println( "afterCompletion: completion is " + comp );
} }

/**********************************
*** with Bean-Managed Transaction Demarcation ***
setSessionContext:
ejbCreate: 15
  guess: num,ans  11,15
  guess: num,ans  33,15
setSessionContext:
ejbCreate: 21
  guess: num,ans  15,21
  guess: num,ans  30,21
  guess: num,ans  16,15
  guess: num,ans  15,15
ejbRemove: 15
  guess: num,ans  22,21
  guess: num,ans  21,21
ejbRemove: 21

*** with Container-Managed Transaction Demarcation and ***
*** a transaction attribute of Required for guess()    ***
setSessionContext:
ejbCreate: 52
afterBegin: 52
  guess: num,ans  33,52
beforeCompletion: 52
afterCompletion: completion is true
afterBegin: 52
  guess: num,ans  66,52
beforeCompletion: 52
afterCompletion: completion is true
setSessionContext:
ejbCreate: 31
afterBegin: 31
  guess: num,ans  22,31
beforeCompletion: 31
afterCompletion: completion is true
afterBegin: 31
  guess: num,ans  44,31
beforeCompletion: 31
afterCompletion: completion is true
afterBegin: 52
  guess: num,ans  51,52
beforeCompletion: 52
afterCompletion: completion is true
afterBegin: 52
  guess: num,ans  52,52
beforeCompletion: 52
  ASKING FOR ROLLBACK
afterCompletion: completion is false
ejbRemove: 52
afterBegin: 31
  guess: num,ans  32,31
beforeCompletion: 31
afterCompletion: completion is true
afterBegin: 31
  guess: num,ans  31,31
beforeCompletion: 31
  ASKING FOR ROLLBACK
afterCompletion: completion is false
ejbRemove: 31
**********************************/



package demos;

import java.io.*;
import javax.rmi.PortableRemoteObject;
import javax.naming.*;

public class GuessGameClient {
  public static void main( String[] args ) throws IOException {
    int guess, response=0, min=1, max=100;
    if (args.length > 0) max = Integer.parseInt( args[0] );
    try {
      InitialContext ic   = new InitialContext();
      Object         obj  = ic.lookup("GuessGameHome");
      HIGuessGame    home = (HIGuessGame) PortableRemoteObject.narrow( obj, HIGuessGame.class );
      RIGuessGame    gg   = home.create( max );
      BufferedReader in   = new BufferedReader(
                                  new InputStreamReader( System.in ) );
      while (true) {
        System.out.print( "Enter guess (" + min + "-" + max + "): " );
        guess = Integer.parseInt( in.readLine() );
        try {
          response = gg.guess( guess );
        } catch (java.rmi.ServerException ex) {
          System.out.println( "  ROLLBACK ON THE SERVER" );
          break;
        }
        if (response == 0) break;
        if (response <  0) if (min < guess) min = guess;
        if (response >  0) if (max > guess) max = guess;
        System.out.println( "  too "
                            + ((response < 0) ? "low" : "high") );
      }
      System.out.println( "bells!!  sirens!!  confetti!!" );
      gg.remove();
    } catch (NamingException ex) { ex.printStackTrace();
    } catch (javax.ejb.CreateException ex) { ex.printStackTrace();
    } catch (javax.ejb.RemoveException ex) { ex.printStackTrace();
} } }

/**********************************
*** with Bean-Managed Transaction Demarcation ***
D:\j2ee> java demos.GuessGameClient
Enter guess (1-100): 11
  too low
Enter guess (11-100): 33
  too high
Enter guess (11-33): 16
  too high
Enter guess (11-16): 15
bells!!  sirens!!  confetti!!

D:\j2ee> java demos.GuessGameClient
Enter guess (1-100): 15
  too low
Enter guess (15-100): 30
  too high
Enter guess (15-30): 22
  too high
Enter guess (15-22): 21
bells!!  sirens!!  confetti!!


*** with Container-Managed Transaction Demarcation and ***
*** a transaction attribute of Required for guess()    ***
D:\j2ee> java demos.GuessGameClient
Enter guess (1-100): 33
  too low
Enter guess (33-100): 66
  too high
Enter guess (33-66): 51
  too low
Enter guess (51-66): 52
  ROLLBACK ON THE SERVER
bells!!  sirens!!  confetti!!

D:\j2ee> java demos.GuessGameClient
Enter guess (1-100): 22
  too low
Enter guess (22-100): 44
  too high
Enter guess (22-44): 32
  too high
Enter guess (22-32): 31
  ROLLBACK ON THE SERVER
bells!!  sirens!!  confetti!!
**********************************/