Introduction – the SeaPort Project series
For this set of project, we wish to simulate some of the aspects of a number of Sea Ports.
Here are the classes and their instance variables we wish to define:
- SeaPortProgram extends JFrame
- variables used by the GUI interface
- world: World
- Thing implement Comparable <Thing>
- index: int
- name: String
- parent: int
- World extends Thing
- ports: ArrayList <SeaPort>
- time: PortTime
- SeaPort extends Thing
- docks: ArrayList <Dock>
- que: ArrayList <Ship> // the list of ships waiting to
- ships: ArrayList <Ship> // a list of all the ships at
- persons: ArrayList <Person> // people with skills at
- Dock extends Thing
- ship: Ship
- Ship extends Thing
- arrivalTime, dockTime: PortTime
- draft, length, weight, width: double
- jobs: ArrayList <Job>
- PassengerShip extends Ship
- numberOfOccupiedRooms: int
- numberOfPassengers: int
- numberOfRooms: int
- CargoShip extends Ship
- cargoValue: double
- cargoVolume: double
- cargoWeight: double
- Person extends Thing
- skill: String
- Job extends Thing – optional till Projects 3 and 4
- duration: double
- requirements: ArrayList <String>
// should be some of the skills of the persons
- time: int
Eventually, in Projects 3 and 4, you will be asked to show the progress of the jobs using JProgressBar’s.
Here’s a very quick overview of the projects:
- Read a data file, create the internal data structure, create a GUI to display the structure, and let the user search the structure.
- Sort the structure, use hash maps to create the structure more efficiently.
- Create a thread for each job, cannot run until ship has a dock, create a GUI to show the progress of each job.
- Simulate competing for resources (persons with particular skills) for each job.
Here are some notes about the projects, the particular features of object-oriented design and object-oriented programming (OOD/OOP) the we want to cover in this class and some of the features of Java to help support that style of programming. We also want to explore the Java GUI system a little, with particular emphasis on viewing the data structures and effective ways to display the running of multiple threads competing for resources.
The particular scenarios selected for each semester ask you to implement as many of these objectives as possible in some compelling way. We are always open to additions and suggestions.
Project 4 General Objectives
Project 4 – Concurrency
- Resource pools o Threads competing for multiple resources
- Blocking threads
- Extending the GUI interface to visualize the resource pools and progress of the various threads.
You should start working on a documentation file before you do anything else with these projects, and fill in items as you go along. Leaving the documentation until the project is finished is not a good idea for any number of reasons.
The documentation should include the following (graded) elements:
- Cover page (including name, date, project, your class information)
- including a UML class diagram
- classes, variables and methods: what they mean and why they are there
- tied to the requirements of the project
- User’s Guide
- how would a user start and run your project
- any special features
- effective screen shots are welcome, but don’t overdo this
- Test Plan
- do this BEFORE you code anything
- what do you EXPECT the project to do
- justification for various data files, for example
- Lessons Learned o express yourself here o a way to keep good memories of successes after hard work
Project 4 Specific Goals:
Extend project 3 to include making jobs wait until people with the resources required by the job are available at the port.
- Reading Job specifications from a data file and adding the required resources to each Job instance.
- Resource pools – SeaPort.ArrayList <Person> list of persons with particular skills at each port, treated as resource pools, along with supporting assignment to ships and jobs.
- Job threads – using the resource pools and supporting the concept of blocking until required resources are available before proceeding.
- The Job threads should be efficient:
- If the ship is at a dock and all the people with required skills are available, the job should start.
- Otherwise, the Job should not hold any resources if it cannot progress.
- Use synchronization to avoid race conditions.
- Each Job thread should hold any required synchronization locks for a very short period.
- When a job is over, all the resources used by the job (the people) should be released back to the port.
- When all the jobs of a ship are done, the ship should depart the dock and if there are any ships in the port que, one of then should should be assigned to the free dock, and that ships jobs can now try to progress.
- NOTE: If a job can never progress because the port doesn’t have enough skills among all the persons at the port, the program should report this and cancel the job.
- GUI showing:
- Resources in pools – how many people with skill are currently available
- Thread progress, resources acquired, and resources requests still outstanding