CMSC 202 Fall 2009

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ship.load( (T) cargo );

Cargo cargo = new Cargo(....);
ship.load( (T) cargo );

Object cargo = new Cargo(....);
ship.load( (T) cargo );

Objectives

• To gain experience implementing a generic class
• To gain experience with the use of exceptions
• To gain experience with an interface

In this project you will use text file I/O to read commands from a file. These commands will tell your ship what functions to perform. Output will be written to a logfile.

You will also be designing and using your own exception classes. The conditions under which an exception is thrown are listed in the details below.

Project 5 is invoked with the following command line arguments in the order listed here.

1. the type of ship -- "cargo" or "cruise" (without the quotes)
2. the name of the ship's port of origin
3. the ship's minimum speed in knots
4. the ship's maximum speed in knots
5. the maximum number of items the ship can carry (regardless of any attributes of the items)
6. the name of the command file
7. the name of the file to which command output and error messages are logged

Your Tasks

1. Copy all the .java files from Mr. Frey's public directory.
2. Read the description of the command file and the requirements section below.
3. Based on those descriptions complete the ProcessComands( ) method in Project5.java. This method reads the command file, calls an appropriate method of the Ship and writes the result to the logfile. Be sure to use good top-down design.
4. Complete the Cargo and Person classes by implementing the methods in the Transportable<T> interface.
5. Implement the Ship class.
6. Implement the TransportException class. This is the only exception class required and the only exception class that should be caught in main( ). Methods that throw the TransportException class should construct the class with an appropriate message.

1. PRINT -- Outputs the state of the ship to the log file. Attributes must be output in the order shown below
   1. the ship's minimum speed
   2. the ship's maximum speed
   3. the ship's current speed
   4. the maximum number of items the ship can hold
   5. the ship's current position (ie. travelling from HERE to THERE or in port at CITY)
   6. details of each "thing" being transported, or an apporpriate message that the ship is empty
   • Cargo items are listed in sorted order by their unique label. All attributes of the cargo item must be listed on the same line.
   • People are listed in sorted order by their unique government-issued ID. All attributes of the person must be listed on the same line.
2. DOCK -- the ship reaches its destination and is tied to the dock, ready for loading or unloading
   The contents of the ship are NOT unloaded.
3. QUIT -- indicates the end of the command file. Your program exits gracefully.
4. LAUNCH <port> -- the ship begins travelling to the specified port at its minimum speed
5. SPEED <new speed> -- the ship changes its speed to the new speed

The formats for LOAD and UNLOAD are different for each type of "thing" the ship is carrying

6. LOAD
   1. a ship carrying cargo: LOAD <unique cargo label> <weight> <height> <width> <length>
      where the label is a string, and the other attributes are integers. The unit of measure for weight, height, width, and length is irrelevant.
   2. cruise ship carrying people : LOAD <Person name> <age> <Unique government issued ID>
      where the name and ID are strings, and the age is a reasonable positive integer.
7. UNLOAD
   1. ship carrying cargo: UNLOAD <unique cargo label>
   2. cruise ship carrying people: UNLOAD <unique government issued ID>

1. If an attempt is made to load an item onto a full ship, log an appropriate message and continue to the next command in the file.
2. If the ship is commanded to travel too fast or too slow, log an appropriate error message and continue to the next command in the file
3. If an attempt is made to unload a non-existent "thing", log an appropriate message and continue to the next command in the file.
4. If the ship is commanded to do something that makes no logical sense given its current state, (e.g. change speed while in port) the command should be disregarded (but still logged), an error message should be logged, and the next command read from the file.

1. Mr. Frey's public directory for this project is afs/umbc.edu/users/f/r/frey/pub/202/Proj5
2. A sample command file and the resulting logfile are available in Mr. Frey's public directory.
3. (Assumption) There are NO weight or volume restrictions when loading "things". The only restriction is on the number of items loaded
4. (Assumption) You may assume that all command file data is valid. In particular this means
   1. The format of the command file will be valid as specified above
   2. The values of all data in the command file will be valid (e.g. positive)
   3. The command file will contain no invalid commands
   4. All command parameters in the file will be the appropriate type (e.g. no Strings when an int is execpted).
   It DOES NOT mean that all commands make common sense. See Exception Conditions above.
5. (Requirement) All commands and their parameters must be logged to the logfile as they are being executed, even if the command is not actually carried out.
6. (Hint) When using Eclipse to develop and test your code, the command file must be located in the base directory for your project at the same level as the src directory. The logfile will be created here as well.
7. (Requirement) Appropriate top-down design for main( ) and its helper methods is required.
8. (Hint) The Java Collections library provides a static method named Collections.sort( ) can be used to sort your cargo and people.
9. (Hint) When passing a Cargo object or Person object to your Ship's load( ) method, it will be necessary to cast it to type T as in ship.load( (T)cargo );
10. Sanity Check: How much code in your ship class, cargo class, and person class would have to change if a third kind of "thing" to be carried (say barrels of oil) were added to this project? If the answer isn't "NONE!!" then you're doing something wrong.

1. You should try as much as possible to complete the project by yourself.
2. You may get assistance only from the TAs or instructors
3. You must document all outside help you get as part of your file header comment.

1. copy anyone else's code
2. have someone else write your code for you
3. submit someone else's code as your own
4. look at someone else's code
5. have someone else's code in your possession at any time

You can check to see what files you have submitted by typing

More complete documentation for submit and related commands can be found here.

Remember -- if you make any change to your program, no matter how insignificant it may seem, you should recompile and retest your program before submitting it. Even the smallest typo can cause compiler errors and a reduction in your grade.

Avoid unpleasant surprises!

Last Modified: Thursday, 07-May-2009 11:46:52 EDT