Lab: Talking Robot

This lab should be done individually. It is okay to get help from the TAs and/or the instructor if you get stuck, but you should try to do it on your own first.

Tip: You should get into the habit of making backup copies of your work.

Some of the hot toys lately have been robots. Consider one particular robot that can walk and talk. Its "conversation" consists of uttering one of several phrases chosen at random, such as "Hey, how's it going?" or "You look marvelous!"

Improved Choice of Phrases based on Time of Day:

Suppose the robot also has a clock, and can be used as an alarm clock. You have been hired by the makers of the robot to help create a new and improved version. Your focus will be to improve its conversational skills by making its choice of phrases depend on the time of day. For example, if it's before 10 am, it might say "Good morning!", "This is way too early for me!", or "Hey, how's it going?" If it's close to lunch time, it might say, "I'm hungry. Let's go eat lunch.", "I'm never going to finish my homework before class!", or "You look marvelous!"

Specifications: You should break the day into at least four time blocks. Time blocks are defined by hours of the day: an hour is an integer between 0 and 23, where 0 represents the hour between midnight and 1 AM, 12 represents the hour between noon and 1 PM, 23 represents the hour between 11 PM and 12 midnight, and so on. For each time block, there should be at least three different phrases that the robot might randomly choose among. At least one or two of those should be time-specific (like "Let's go eat lunch!"). Others can be more generic. Generic phrases can be used in multiple time blocks if you want. For example, you could decide to include "Hey, how's it going?" as a possible phrase in every time block if you want. On the other hand, time-specific phrases should not be among the possibilities in inappropriate time blocks. You will have to write your randomly-chosen phrase to the console, since you don't have an actual robot to program.

Design: For this program, you will use 3 classes: an application class containing the main method, a class representing robots, and a class representing a clock. The main method will construct a robot and ask it to utter a time-appropriate random phrase. The robot will ask the clock for the current hour of the day in order to decide on possible phrases to use. The class diagram below shows the three classes and shows that the RobotLabApp application class uses an object (or more than one objects) of the Lab2TalkingRobot class, and that robot objects use the Clock class. (You may use the same class names as the diagram, although you do not need to.)

Before starting to implement your talking robot, take a few minutes to plan which time blocks you are going to use and identify at least one phrase for each time block.

Implementation: One common process for developing software is to develop it in small increments, testing the program at every step to ensure that you have a working program all along the way.

• To begin this program, download the skeleton TalkingRobotLabUsingBlueJ program, unzip it, and test to see whether it compiles and runs.

  Stop and Think: Read the source code for the main method; given what you see there, does the behavior you saw when you ran the program make sense to you? Read the source code for the robot and clock classes. Notice that the robot constructor constructs a clock object. Are any clock methods called yet? Does the robot class have any methods beyond its constructor? Does the clock's getHour method return the hour of the current time of day? (You should be able to answer the last question just from the documentation comments for the class.)

  Note: The Clock class claims to be a "stub" class. A stub class is a very simplified version of a class used for testing purposes, or as a temporary measure when the real class hasn't been developed yet. It must have all the public methods of the class, but they often do not do anything, or do as little as possible to get the rest of the program to compile and run.

• Once you know that you have a working program, modify it to welcome the user to Lab 2 rather than Lab X, recompile, and test. If you want to change the name of any of the classes, use the Find selection from the Tools menu to find and replace every occurence of the old class name (including the name of the constructor!) with the new class name, recompile, and test.
• Modify the main method to construct a robot, recompile, and test. (Should the program behavior be any different when you test this time, compared to when you tested last time?)
• Add a method for saying a phrase to the robot class. For now, just have the method print any phrase you want -- this is incremental development. Modify the main method to call the new method, recompile, and test. (You could have tested after you added the method to the robot class but before you called it from the main method. Would you have learned anything from that test?)
• Update the class and method documentation in the class in which the main method appears.
• In your new method, get the hour from the clock and store the result in a variable. Then print it in order to test that you are getting the "current" hour correctly. (Is it really the
"current" hour?) Test the program several times to make sure that you get expected results.
• Modify your new method again to print a simple phrase that depends on the "current" time block. For example, if one of your time blocks is 3am - 10am, you might want to just print "Good morning" when the current time falls in that block. Will one test run adequately test this modification?
• Modify your method to print out a single, unique, time-specific phrase for each time block you identified earlier. What do you need to do to test this modification?
• Re-read the source code for the Clock class to see how to construct and use a random number generator. (Note: The Random class is a standard Java class, but to use it in a class you must remember to include an import statement like the one at the top of the Clock class.) Modify your program so that for one of your time blocks you randomly print one of several possible phrases. What do you need to do to test this modification?
• Modify your program to randomly print one of several possible phrases for each of your time blocks. You may have some phrases that occur in multiple time blocks if you want.
• Be sure to edit the comments in the robot class as appropriate, including the class documentation comments at the top of the file. Providing proper documentation is an important step towards writing well-structured and reusable programs.

Optional Enhancement: Using a random number to represent the current time makes testing easier, because otherwise you would have to test it at various times during the day. You could improve the Clock class to actually use the current time by modifyng it to use the standard Java Calendar class. To get a Calendar object whose fields are initialized with the current date and time, you would need a statement such as: Calendar rightNow = Calendar.getInstance(); To get the current hour of the day, you would need to use a statement such as: int timeOfDay = rightNow.get(rightNow.HOUR_OF_DAY); If you have time at the end of lab you may experiment with the Calendar class if you like, but be sure that your program is working with the random number first.  If you do choose to update the Clock class in this way, also update its documentation comments and hand in your modified Clock class with the rest of the lab.

• When you are done, hand in the class with the main method, your modified robot class, and the Clock class if you modified it to use the Calendar class.

When you complete the lab, you can start work on Programming Project #2 (due at the beginning of Lab 3).