CS 110: Introduction to Programming in Java
	Kalamazoo College
	Spring 2008

Exercise 1: Creating a Folder for your CS 110 work

It makes sense to keep your CS 110 programs together in a single place, separate from other documents or materials you may have from other classes.

1. Double-click on the "My Computer" icon on the desktop.
2. Double-click on the folder associated with your ID (e.g., k03xx01).  Note: if there isn't an icon for your server directory under "My Computer," you will need to follow the following instructions to get to Dragon the long way. If you need to use this convoluted way to get to Dragon now, chances are you will need to use it repeatedly throughout this course, which is why it is getting so much prominence here.

   Getting to Dragon the long way... (only if necessary) Click on "My Network Places" on the Start menu In the "Other Places" box, click on "Entire Network" Double-click on Microsoft Windows Network Double-click on Knet You will see many machines listed; double-click on Dragon In this case, since you are looking for your own space on the network server, double-click on Students and then on the folder with your own Knet ID (e.g., k03xx01).  In other cases, when you are looking for CS 110 materials, from Dragon you will double-click on the cls_compsci folder.

3. Create a new sub-folder named CS 110 (or something similar) in your folder. Throughout this course, you will be creating new sub-folders in this space.

Exercise 2: Creating a Program Using Eclipse

An object-oriented program is, as we learned in class, made up of a collection of classes.  Each class is stored in a separate file, where the name of the file is the name of the class with a .java extension.  Thus, a class called Aquarium must be in the file Aquarium.java.  We might have many classes in a program, and we might have many programs.  How do we keep track of which classes are part of which programs?

The Eclipse development environment uses the idea of a project to keep track of information about a program, such as which classes are part of the program, where the program's starting point is, and so on.  To run or modify a program using Eclipse, the first thing to do is to start up Eclipse and then create a new project or open an existing project to contain and keep track of our classes.

We also learned in class that a running program consists of objects invoking operations on other objects.  How, though, can we start an application when it doesn't have any objects yet to do any operations?  The answer is that at least one of the classes in an application must have a special operation called main.  (The definition of an operation in a class is called a method definition, so this operation is called a main method.)  A main method is not tied to any particular object, so the development environment (or whatever software is running the program) can invoke it, even though it doesn't have any objects yet.  The main method then constructs one or more objects and invokes operations on them.  They, in turn, may construct objects and invoke other methods, which is the essence of an object-oriented program.  To start a Java application, Eclipse looks through the project for a class that has a main method and invokes it. 

Let's start by creating a very simple program with a single class. To keep things simple, the only method we will create is a main method.

• Start up Eclipse.  Click on the "Start" menu at the lower left-hand corner of your screen.  Move the mouse up to the "All Programs" menu name, and then move the mouse to the right until a pop-up submenu appears.  At the top of the submenu is a list of folders; below that is a list of applications.  Move the mouse over the word "Eclipse", then move the mouse right again and select the "Eclipse" application from the pop-up submenu. You may close the "Welcome" tab if it appears.  If you get a "Workspace Launcher" dialog box, click on the Browse button and browse to your CS 110 folder under "My Computer" (or following the long way to Dragon outlined in the box above).  When you get to your folder, click on "New folder" and give it a name, such as EclipseWorkspace.
• Create a new project.  In the Eclipse "File" menu, move the mouse to the "New" menu item.  In the pop-up submenu that appears, select "Project."
  • A new window will appear. Make sure that "Java Project" is selected.  Click on the "Next>" button. 
  • Give your project a name, such as Lab1, Simple Project, Experiment, or some such name.  Click on the "Create project from existing source" checkbox. For the location, you want to specify your own directory.  Click on the "Browse" button to do this. 
  • In the pop-up window that appears, click on the plus sign next to "My Computer" and then choose your directory on the campus server (or click on the plus sign next to your directory and choose the folder you created for this course).  Click on the "New Folder" button to create a new folder for this project.  Without clicking anywhere, type in a new name for the folder.  (If this doesn't change the folder's name in the navigation pane, click on the "New Folder" label until the name appears in a box with a cursor; then type in the new name.)   Click on the "OK" button.
  • Don't bother with the "Next>" button, just click on the "Finish" button.  If you get a dialog box asking about the Java Perspective, just click "Yes."
  • You should see a folder with the name of your new project appear in the "Package Explorer" pane on the left side of the Eclipse window.
• Import the proper style preferences. Select "Preferences" from the bottom of the Eclipse "Window" menu.
  1. Import code format conventions
     • Click on the plus sign next to "Java" in the left window pane.  Click on the plus sign next to "Code Style."  Click on " Formatter."  In the right pane, click on the "Import" button.
     • In the pop-up window, navigate to the cls_compsci folder on Dragon.  (You may find yourself there already.  Otherwise, see if there is a "KNet" folder; if so, click on it and then click on Dragon.  If you cannot find Dragon more directly, you will have to navigate there the long way, through "My Network Places" following the directions outlined in the box at the beginning of this document.)  Once you have reached the cls_compsci folder on Dragon, select the "CodeFormatConventions.xml" file and click on the "Open" button.  If a dialog box appears, click on the "OK" button.
     • Click "Apply"
  2. Import comment templates
     • In the left pane, now click on "Code Templates".  In the right pane, click on "Comments".  Click on the "Import" button.
     • In the pop-up window, navigate to the cls_compsci folder on Dragon as before.  Select the "EclipseCodeTemplates.xml" file and click on "Open".  If a dialog box appears, click the "OK" button.
     • Click "Apply"
  3. Click on the "OK" button in the Preferences window.
• Create a new class.  In the Eclipse "File" menu, move the mouse to the "New" menu item.  In the pop-up submenu that appears, select "Class."
  • A new window asking for information about your new class will appear.   You don't have to worry about most of the fields in this window, just choose a name for your class (such as SimpleClass or something along those lines) and then click on the public static void main checkbox (one of a set near the bottom of the window).  Also click on the generate comments checkbox at the bottom of the window.   Then click on the "Finish" button.
  • You should see an icon labeled "(default package)" with another icon for your new class appear under the folder for your project in the "Package Explorer" pane on the left of your Eclipse window.
• Edit the new class.  You should notice the tab above the central editing pane in your Eclipse window labeled with the name of your new class. 
  • When there is more than one file active you can click on each tab to move to the other files.  By clicking on the "X" that appears on the tab when that tab is selected; you can close that file. 
  • Scroll up and down in your class.  Notice that there are two sets of comments about your class.  The first set, preceded by "//" on each line, will contain basic information about the name of the class, who created it, and how it has been modified.  The second set, enclosed in "/** ... */" comment markers, will describe what assignment this class was created for, what the purpose of the class is, and, again, who created the class.  This is a special "javadoc" comment that could be used by the "javadoc" tool to create an HTML file with documentation about your class. 
  • Edit the "javadoc" comments for your new class.  Change the one-sentence description to indicate that this is a test class to experiment with creating a new class in a new project.  Delete the sentence saying "A more detailed description goes here..." (unless you want to replace it with a more detailed description of your class).  Either edit or delete the second @author line, depending on whether you are working with a partner or individually.
• Run your new program.  In the Eclipse "Run" menu, move the mouse to the "Run As" menu item.  In the pop-up submenu that appears, select "Java Application." If you haven't saved your modified file yet, you will be prompted to do so. You may see a quick task bar as the program compiles, but then you won't see anything interesting, because your program doesn't actually do anything.  Yet.
• Edit and run again.  Find the line of code that says "public static void main(String[] args)".  Don't worry about the fact that this line of code doesn't mean anything to you now -- we will learn about it soon. Move the mouse to the right of the open brace ("{") after the "public static void main" line.  Hit the Enter key.  You should see a new line open up, and the mouse should be indented about 4 spaces in from the open brace.  Type

      System.out.println("Hi");

  This line won't mean anything to you either, just type it.  Notice that the Eclipse editor is trying to be smart.  As soon as you type in the left parenthesis and double-quote mark, it will add the right parenthesis and second quote mark.  If you type the second quote mark and then the right parenthesis yourself, it will just move over the characters it added for you.  Alternatively, you can use the mouse or arrow keys to move past the characters it added.  Don't forget the semi-colon (not a period or colon) at the end of the line.  Now you can run your program again as you did above, or you can click on the icon of a green circle with a white triangle (beneath and between the :Refactor" and the "Navigate" menus).  If a "Run" pop-up window appears asking you to create, manage and run configurations, just click on "Run" at the bottom.  If you didn't save your modified class, you will be prompted to do so.  This time you should see the word "Hi" appear in the Console pane beneath your class.
• Creating documentation for your program. In the Eclipse "Project" menu, move the mouse to the "Generate Javadoc..." menu item. In the pop-up window that appears, go to the "Javadoc command" prompt, and navigate to, and select, "C:\ProgramFiles\Java\jdk1.5.0_04\bin\javadoc".  Then click on the "Finish" button. If a dialog box appears, click on the "OK" button. Eclipse will generate the documentation - the console window will show your progress. When the word "terminated" appears next to the word "Console" on the Console window, the documentation generation is complete. In the Navigator pane, click on the plus sign next to the folder "doc" and then double click on the file index.html. This will bring up your documentation in a browser tab within Eclipse. Explore the documentation that has been generated. The documentation for this program is not very interesting but it does show you how easy it is to create documentation that matches your program comments. When you are finished exploring, click on the "X" at the top of this tab to close this browser. We will use the "javadoc" tool again later in the quarter.
• Click on the "X" on the tab for your class to close that file.

Exercise 3: Dragging Files from Dragon

Many of the labs and programming assignments in this course will involve modifying existing programs provided for you on the college's server called "Dragon."  For example, in the first few weeks of the course you will be developing an Aquarium program.  You will be writing all of the logic that actually runs the program, but we will provide graphics code that your program will use.  Thus, you will start by copying an existing program with the graphics code already in place, and then modify it.  The versions of all the CS 110 programs on Dragon will also include the necessary Eclipse project information for you to run the programs under Eclipse.

To run and modify the programs we provide on Dragon, you will first have to copy them to somewhere where you have the correct permissions, such as your directory on the campus server or your computer in your dorm room.  The directions below assume that you are working in a lab and want to copy.

1. Bring up a window showing the files that you want to copy.
   1. Double-click on the "Knet" icon on the desktop.  In the Knet folder you will see a number of machines listed.  Double-click on Dragon.  [Note: If there isn't a Knet icon on the desktop, then you'll have to get to Dragon the long way outlined in the box at the beginning of this document.]
   2. Once you're in the Dragon folder, double-click on cls_compsci.  (This is where computer science classes have their Knet archives.)
   3. Double-click on cs110.
2. Bring up a window showing the folder to which you want to copy the files.  For example, to copy the files to your directory on the campus server, do the following:
   1. Double-click on the "My Computer" icon on the desktop.
   2. Double-click on the folder associated with your ID (e.g., k03xx01).  [Note: if there isn't an icon for your server directory under "My Computer," follow the instructions above to get to Dragon the long way, and then double-click on the "students" folder and then on your own directory.]
3. Drag the appropriate folder or files from the cs110 folder in one window to your own folder for this class in the other window. For this lab, drag the JavaMBSUsingEclipse folder.

Exercise 4: Opening and Running an Existing Program Using Eclipse

For this part of the lab, you will copy and run the Marine Biology Simulation program.

• If you haven't done so already, copy the JavaMBSUsingEclipse folder from the cs110 folder under cls_compsci on Dragon to your own folder on the campus server.
• Start up Eclipse if it isn't already running.
• Select "Import" in the Eclipse "File" menu.
• In the window that appears, choose "Existing Project into Workspace" and then click on the "Next>" button.
• Click on the "Browse" button and navigate to the "JavaMBSUsingEclipse" folder in your directory on the campus server.  Select the "Chaps1and2MBSGUI" folder and then click "OK."
• Click on the "Finish" button.
• You should see a folder labeled "Chaps1and2MBSGUI" appear in the "Package Explorer" pane on the left side of the Eclipse window.  Click on the plus sign next to it.  Then click on the plus sign next to the "(default package)" folder.  Then click on "MBSGUI.java" to select it.  In the Eclipse "Run" menu, move the mouse to the "Run As" menu item.  In the pop-up submenu that appears, select "Java Application."
• After a few seconds the window for the Marine Biology Simulation should appear.

Exercise 5: Experimenting with the Marine Biology Simulation Program

• In the Marine Biology Simulation window, go to the File menu and choose "Create new environment..."  This will bring up a dialog box that will allow you to choose the dimensions for the bounded environment (e.g., the pond) in which the fish will swim.  You can set your own dimensions or use the 10 x 10 provided by default.  Then click on Create.
• Now you should see the empty environment on the left, with grid lines showing the cells where the fish could be.  On the right-hand side of the window you will see two drop-down menus.  The first lets you choose the type of object to add to the environment, but for now "Fish" is the only choice.  (We will see how to change this later in the quarter.)  The second menu lets you choose what color you want your fish to be.  The "Random" choice will give each new fish a randomly selected color.  To actually create fish in the environment, click on the cell where you want the new fish to be created.
• Experiment with constructing a number of fish in different cells.  What happens if you try to put more than one fish in the same cell?  Try clicking five or more times in a single cell.
• Experiment with the Step and Run buttons and the speed slider.  Can you figure out what rules govern fish behavior?  We will come back to this question, and to the Marine Biology Simulation program, later in the course when we are ready to work with a relatively large program.
• Exit the Marine Biology Simulation program by choosing File -> Quit or by closing the window.

Exercise 5: The Edit-Compile-Run Cycle

Now let's return to a project you were working on before, to add new functionality to it.  You will do this frequently in this course, since enhancing an existing program (editing, compiling, and testing existing files) is much more common than creating a completely new one.  In fact, since it is almost impossible to sit down and write a program absolutely correctly from scratch, even new programs are often created by modifying previous programs.

• In the Package Explorer pane, select the project you created in Exercise 2 above.  If you can't see the class you created indented below the project, click on the plus sign next to the project folder.  (You might need to click on a plus sign next to the "(default package)" icon also.)  Click (or double-click, if necessary) the class you created.  You should see it appear in the central editing pane.
• Now let's edit and personalize the program. Scroll down to the System.out.println statement you added earlier.  Replace the string between the double quotes to make the program print out "Hello, your name" instead. Run it again. Did you get what you expected? If not, fix it!
• The name you chose earlier for your class is probably not very descriptive.  Change its name to a more descriptive name for this class.  The name should start with a capital letter, since this is the convention for class names in Java.  Eclipse provides an easy way to change the class's name in a consistent way.
  • Select the class in the Package Explorer pane.
  • In the Refactor menu, choose "Rename."
  • In the dialog box that appears, enter the new name.  Mark the checkbox so that any references to the class name in your code or in comments will be changed as well.
  • Click on the "Preview" button.  If your class contains a "main" method, you may get a warning about other classes that might use this one.  You can just click on "Continue" to proceed.  You will get another pop-up window informing you of what changes are to be performed.  Click on "OK".
  Note that the name of the class in the Package Explorer pane changed.  Scroll through the class to make sure that other necessary changes were made also.  Update the class description in the "javadoc" comments.
• You can also give the project a more meaningful name. Select the project name in the Package Explorer pane and then choose Rename in the Refactor menu.  After doing this, you may need to click on the plus sign next to the project name to open it up and see its contents.
• You should also change the name of the directory containing your project, to make it easier to find next time.  Select your project in the Package Explorer pane and then choose "Move" in the Refactor menu.  In the dialog box that appears, change the name of the directory (the last segment of the Location name) to the same name as your project.  Click on the "OK" button.

Exercise 6: Cleaning Up

Be sure to clean up the Eclipse workspace before you go, so that the next person to use the same machine does not see your files.  One at a time, choose each project and then select "Delete" under the "Edit" menu.  In the confirmation dialog box that appears, be sure that you check "Do not delete contents"!!!

Make sure that you saved your program to your directory on the campus server or a disk on your own network.  In addition, you may wish to save a backup copy in one of those two places, or on a USB drive.

When you complete the lab, you can start work on Programming Project #1 (due at the beginning of Lab 2).