Language/Platform

This project must target a Unix platform and execute properly on our cs1 Linux server.

The project must be written in C, C++, or Java.

If using C or C++, you must use POSIX pthreads and semaphores.

If using Java, you must use Java Threads and Java Semaphores (java.util.concurrent.Semaphore). 

You should not use the synchronized keyword in Java.

You should not use any Java classes that have built-in mutual exclusion.

Other mechanisms for thread coordination require instructor approval.

Hotel Simulation

A hotel is simulated by using threads to model customer and employee behavior.

This project is similar to the barbershop example in the textbook. The following rules apply:

Overview

The hotel to be simulated has two employees at the front desk to register guests and two bellhops to handle guests bags. A guest will first visit the front desk to get a room number. The front desk employee will find an available room and assign it to the guest. If the guest has less than 3 bags, the guest proceeds directly to the room. Otherwise, the guest visits the bellhop to drop off the bags. The guest will later meet the bellhop in the room to get the bags, at which time a tip is given.

Threads:

Guest:

1)25 guests visit the hotel (1 thread per guest created at start of simulation).

2)Each guest has a random number of bags (0-5).

3)A guest must check in to the hotel at the front desk.

4)Upon check in, a guest gets a room number from the front desk employee.

5)A guest with more than 2 bags requires a bellhop.

6)The guest enters the assigned room.

7)Receives bags from bellhop and gives tip (if more than 2 bags).

8)Retires for the evening.

Front Desk:

1)Two employees at the front desk (1 thread each).

2)Checks in a guest, finds available room, and gives room number to guest.

3)A guest must receive their room key before the front desk employee can register the next guest.

Bellhop:

1)Two bellhops (1 thread each).

2)Gets bags from guest.

3)The same bellhop that took the bags delivers the bags to the guest after the guest is in the room.

4)Accepts tip from guest.

Other rules:

1)All mutual exclusion and coordination must be achieved with semaphores.

2)A thread may not use sleeping as a means of coordination.

3)Busy waiting (polling) is not allowed.

4)Mutual exclusion should be kept to a minimum to allow the most concurrency.

5)Each thread should print when it is created, and main should print when it joins the customer threads.

6)Each thread should only print its own activities. The guest threads print guest actions and the employee threads print their own actions.

7)Your output must include the same information, same wording, and the same set of steps as the sample output. Of course, each run can be different depending on the order of thread execution and the random assignments made.

Output

1)Each step of each task of each thread should be printed to the screen with identifying numbers so it is clear which threads are involved.

2)Thread output sample for 3 guests. The wording in your output should exactly match the sample.

Simulation starts

Front desk employee 0 created

Front desk employee 1 created

Bellhop 0 created

Bellhop 1 created

Guest 0 created

Guest 1 created

Guest 2 created

Guest 0 enters hotel with 1 bag

Guest 1 enters hotel with 4 bags

Guest 2 enters hotel with 3 bags

Front desk employee 0 registers guest 0 and assigns room 1

Front desk employee 1 registers guest 1 and assigns room 2

Guest 0 receives room key for room 1 from front desk employee 0

Guest 1 receives room key for room 2 from front desk employee 1

Front desk employee 0 registers guest 2 and assigns room 3

Guest 0 enters room 1

Guest 2 receives room key for room 3 from front desk employee 0

Guest 1 requests help with bags

Guest 0 retires for the evening

Guest 0 joined

Guest 2 requests help with bags

Bellhop 1 receives bags from guest 2

Bellhop 0 receives bags from guest 1

Guest 1 enters room 2

Guest 2 enters room 3

Bellhop 0 delivers bags to guest 1

Bellhop 1 delivers bags to guest 2

Guest 1 receives bags from bellhop 0 and gives tip

Guest 2 receives bags from bellhop 1 and gives tip

Guest 2 retires for the evening

Guest 1 retires for the evening

Guest 1 joined

Guest 2 joined

Simulation ends