Karel J Robot Simulator User's Guide Page 1
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1. import kareltherobot UrRobot import kareltherobot World import kareltherobot Directions If you give your robots color badges you also need to import java awt Color You should write one only one public class in each java file Inner classes if you use them don t count here They may be public or private as you prefer Your robot class will need at least one constructor Each of your constructors must invoke one of the two constructors of its superclass unless that superclass happens to have a no argument constructor UrRobot and Robot do not have such constructors so you need to invoke super in most cases giving a street avenue Direction number of Beepers and optional a badge color Usually you just provide a constructor with these same parameters public StairClimber int street int avenue Direction direction int beepers Color color Page 13 Karel J Robot Simulator User s Guide super street avenue direction beepers color In some problems it makes sense to use default values for some of these so the constructor form isn t strictly required but the super call must supply some values for each argument For example if the problem requires that all such robots carry an infinite number of beepers then the constructor might reasonably be public RoomFiller int street int avenue Direction direction Color color super street avenue direction infinity color The Color pa2. If your class was in a java package then a new sub folder with the package name has been created in your working directory and it contains one or more files with the class extension If it is not in a package then the class files are in your working directory You have then completed the first step You need to repeat this if you ever change StairClimber java but not otherwise Once you have created the class files with the compiler you may execute the code by using the interpreter We continue to assume that your StairClimber class contains a proper main function Then to execute this main function beginning the simulation issue the command java cp KarelJRobot jar StairClimber If you put your class into a package named say karel then the class files will be in the karel subdirectory and the above command changes to java cp KarelJRobot jar karel StairClimber but is issued from the working directory and NOT from the karel subdirectory Note that if the main function of the class does not contain a command World setVisible true then the simulation window will not appear See the section on Worlds in this document There are a few versions of the JDK in which you might have to spell out the cp option as classpath instead Page 2 Karel J Robot Simulator User s Guide 2 2 BlueJ BlueJ is an IDE intended for novices It is very nice and has a class design layer as well First get BlueJ from http www bluej org Instal
3. To change the number of streets or avenues in the world enter an integer into the corresponding text field and hit enter Note that this doesn t restrict the world in any way It just determines how much of it is drawn with street and avenues Save your world whenever you like I ve used an extension kwld here but there is nothing special about it It is neither assumed nor automatically appended You can also open an existing world to edit modify it The Clear World button will remove all elements from the world Be careful there is no UNDO here Quit the world builder by closing either of its windows If your world has been modified since the last Save you will be prompted to save it again Note that if you QUIT using a menu or command key this extra Save prompt will NOT occur If you use an IDE and want to run from there make a separate project for this and include the jar file Make kareltherobot WorldBuilder the main file for the project In Codewarrior on the Page 10 Karel J Robot Simulator User s Guide Macintosh at least you need to set the output to be a class folder rather than a jar file since the main is in the existing jar file and not in any code of your own After you build this class folder will be empty 800 Karel J Robot 10 Streets test kwid Here is the World Builder running on a Macintosh OSX The look is similar on other platforms Since i
4. World readWorld test kwld World setVisible true The world file will be opened and its content merged into your existing world If you store your world files in a directory other than the working directory for your project there is another form of the readWorld method in which you can name a path to your file in a separate first parameter See the JavaDocs for Karel J Robot for details The world is not visible by default here so the set Visible command is needed Note on the files created by the world builder The format is compatible with that of the very early Karel J Robot simulators However there is no need to use the older version as this is an extension You can actually write the world files with a text editor Lines that do not start with a keyword for the builder are ignored Elements can appear in any order They are NOT case sensitive Here is a sample file KarelWorld Streets 10 Avenues 20 beepers 3 4 beepers 4 2 eastwestwalls northsouthwal northsouthvall northsouthvall northsouthvall HS NnnN o W HS BP owhNh BE Aa O1W N The first line KarelWorld is not a keyword but it might be in the future It might also contain a version number eventually It is ignored when reading now but written when you save a world The following gives the meaning of the current keywords This is not expected to change e Streets The number of streets to draw e Aven
5. again run Finally if your response is w or W then follow that letter with a space and then the name of a new world file to be loaded before your program is run With this last option you can run the same program in different worlds without quitting If you don t give the w option the same world if any will be loaded again Note that on the Macintosh under OS 9 there is normally no command line so there the last form of the run is equivalent to double clicking on the application jar file that your IDE Codewarrior for example creates But that only works if you make kareltherobot KarelRunner your main class of course This is the case if you use ANY IDE on the Mac or otherwise Also if you run a task in which all robots run in separate threads the prompt for rerun will come immediately after the robots are created This can be a little disconcerting as the task hasn t run yet and you are being asked to run it again Eventually the robots will complete and your response to this prompt will have effect NOTE March 15 2003 KarelRunner was called KarelTest until recently RobotTask was previously called RobotTester This is a change for naming consistency with other items in the system Also note that a RobotTask class should not also extend a robot class These task classes only work if they have a no argument constructor available and usually robot classes do not have such a constructor RobotTasks are to exercise robot classes not to B
6. create a project for each program though a program may consist of many files A project contains all the necessary files and it manages the compiling and running of your code itself Create a working directory for yourself and put the files extracted from the distribution zip file there Page 8 Karel J Robot Simulator User s Guide Open JBuilder and select New Project from the File menu Give your project a name and navigate to the folder in which you want to store the files I suggest a subdirectory of your working directory Click Finish You will now have a project AND a new directory Copy KarelJRobot jar to this new directory along with any world files and any already existing java files you want in the project Go back to the project itself and right click on its icon in the left pane of the IDE Select properties from the bottom of the menu Click the Paths tab then the Required Libraries sub tab Click Add In the new Dialog click New Type a name into the top field of the new dialog Karel set the Location to be Project and click Add In the next dialog navigate to the KarelJRobot jar file and select it Click OK Back at the earlier Dialog click OK again Back in a yet earlier dialog select the name you just added to Project and click OK Back in the properties dialog click OK once again From the Project menu you can select Add Files Packages to add additional files to your project or you can create them with New from th
7. compiler javac and then you need to run it with the runtime interpreter java You will need a command shell window for both of these and you will need to set your current directory to your working directory by giving the directory change command in your command window Usually this is done with the cd command You always work from this directory The prompt in the command window probably shows you which directory you are connected to which is current Suppose you have written a robot program stored in StairClimber java Its public class is StairClimber and suppose also that you have a main function in this class Then to compile this class and make it available for the interpreter you give the following command on a PC javac d cp KarelJRobot jar StairClimber java Notice the period after the d option and a space If you are running on a unix machine including linux and Mac OS 10 x replace the single semicolon in the above with a colon Each is the respective path separation character Note that everything here should be considered case sensitive even if your system the PC for example has a case insensitive file system The java tools like javac are case sensitive If you get an error that suggests the javac command is not found your java installation is incorrect If there are errors in your java file they will be reported to you in the command window They must be fixed and the above command reissued until it succeeds
8. give an executable specification of a robot program using this fixture by creating a table within FitNesse Here is an example Here is what a specification for the StairClimber task looks like in this system Page 20 Karel J Robot Simulator User s Guide kareltherobot KarelFixture kareltherobot StairClimber Tester kareltherobot KJRTest local World reset Read World stairworld kwld Create karel 1 East 0 Message __ karel getBeeper Assert BeepersInWorld 0 Assert BeepersinBeeperBag karel Assert FacingEast karel Assert NotRunning karel Assert At karel 4 4 It is important to note that this is an executable specification You execute it by pushing a test button on the page that contains it not here visit the link above When you test it with a correct program you get something like kareltherobot KarelFixture kareltherobot StairClimber Tester kareltherobot KJRTest local World reset Read World stairworld kwld Create karel 1 East 0 Message Xarel getBeeper Assert BeepersInWorld 0 Assert BeepersinBeeperBag karel Assert FacingEast karel Assert NotRunning karel Assert At karel 4 4 10 Additional Features 10 1 Color The standard color used to draw the streets and avenues is a dark red You can change this by sending the World a message World setStreetColor Color blue Page 21 Karel J Robot Simulator User s Guide will set the streets and avenues to blue You must import java awt Color for th
9. named TrivialApplication java to your project You can either discard this or edit it renaming it as appropriate Remember that Java expects the file name and its single public class to have the same name So if you edit it you may need to Save AS so that you can change the name You can also create new files and add them to your project Next you need to tell CW what your main class is In the project window there is a set of buttons near the top One of them looks like a page with wings to the left brings up the project options not the same as IDE preferences from the Edit menu It is also found at Java Application and Release Settings in the Edit menu In the project options select Java Target and fill in the name of your main class It is TrivialApplication by default and you need to edit this Remember also that the name of a class includes its package structure so if KarelMain is in package karel then you need to enter karel KarelMain into the main class field You can set other options of course but if you work on a Macintosh OS 9 you should leave the Java Output option set to its default jar file though the name doesn t matter This is because OS 9 has a limit on the length of file names and with package prefixes these can get quite long for inner classes Files in a jar don t have this restriction Save your changes to the project options and close the window World files should also go in the project folder so that they ca
10. select the org junit folder currently org junit 3 8 1 but this may change Inside that folder select junit jar and click Open Then click Finish 2 Find the window in your operating system that you used to unzip the distribution and drag the KarelTheRobot jar file over the Project icon in the Hierarchy pane and drop it there Alternatively you can add this as an external jar just as you did the junit jar above Only the navigation will be different 3 Right click again on the new project file with the name you just created Select New gt Package in the popup menu Give this package the name karel without the quotes and with no capitalization You will create your classes in this directory Note that this assumes you want your classes in the karel package If you don t want to use packages at all though really you should you can skip this step altogether If you don t want packages you will be using the default package in any case Page 5 Karel J Robot Simulator User s Guide You can drop existing java files onto this package icon provided they have a package karel statement at the beginning of course You can also create new classes Right click on the package icon and select New gt Class Give your class a name and a superclass You may want kareltherobot UrRobot perhaps if you are creating a class of robots You can browse to the superclass with the Browse button That opens a window that has a search field at the t
11. the future At that time StairClimber was in that package also Page 17 Karel J Robot Simulator User s Guide AAA Karel J Robot O O O kareltherobot StairClimber 0 control eee ACRE Se turnoff O T toString o O The first argument in the constructor of an AutoRemote is the fully qualified name of the robot class to instantiate AutoRemote itself has another constructor without a Color but your class must implement the constructor with signature public MyRobot int street int avenue Direction direction int beepers Color color or you will get an Exception You can create as many of these as you like in your main of course AutoRemote has a constructor with no arguments to create an UrRobot at 1 1 facing North with no beepers AutoRemote has another constructor with a single argument to name the class whose robot should be created It will be created at 1 1 facing North with no beepers This is much like what you get with RobotController described above 7 Stepping Robots You can now step through the operation of your robot programs There are two options for this Primitive stepping and User stepping Page 18 Karel J Robot Simulator User s Guide 7 1 Primitive Stepping You can make any robot pause just before executing any of the primitive instructions defined in Chapter 3 of the text or any of the predicates defined in Chapter 5 of the text with this fe
12. E robots For example the RobotTask above class Testl exercises UrRobots 6 Remote Control of Robots There are two ways to remotely control a robot You can use these to directly control a robot rather than writing a program that does so A simple remote controller is a dialog linked to a UrRobot These are created together Here is a pair of commands that creates two robots and their associated controllers See Color in the Additional Features section of this document RemoteControl controller new RemoteControl 5 3 East 0 Color red RemoteControl controller2 new RemoteControl 1 2 North 0 null Page 16 Karel J Robot Simulator User s Guide Move Turn Left Pick Beeper Put Beeper Turn Off Notice that a robot with a red badge has a controller with a red background and one with no badge has a white background Once you have the remote controller you control the robot by pressing the buttons While the above will only create a remote controller for a UrRobot you might want something similar for your own classes Suppose you have StairClimber java and want a controller From a main or task block you can create an AutoRemote World readWorld stairworld kwld AutoRemote climberControl new AutoRemote kareltherobot StairClimber 1 1 East 0 Color red Note that when this was written it was necessary to create classes used by AutoRemote within the kareltherobot package This will be changed in
13. Karel J Robot Simulator User s Guide Joseph Bergin Co opsrg ht 2005 Joseph Bergin ts e 1 l 21 ae 10 SE 10 5 4 1 C ronzona Wall 5 6 8 9 10 Gus Program mer Karel J Robot Simulator User s Guide Karel J Robot Simulator User s Guide Joseph Bergin March 15 2005 This guide is Copyright 2005 Joseph Bergin All rights reserved The software it describes may be obtained online or from the book s site below The software may be freely copied and distributed 1 Introduction This guide will explain the workings of the simulator that accompanies the text Karel J Robot A Gentle Introduction to the Art of Object Oriented Programming in Java The text is available from http www cafepress com kareljrobot This document will not describe how to program in the Karel J Robot KJR world For that you need the book 2 Using the Simulator in Various Environments 2 1Just the JDK You may want to use KJR without any integrated development environment IDE at all For this you only need the Java Development Kit JDK from http java sun com Any version of the JDK since Java 1 1 7 should do though a few of the older ones were buggy The simulator was written being very cautious about features so that it should run well on older versions It has not been tested with Java 1 5 Java 5 however Install the JDK and take all
14. ature The robot will pause until you type a return enter into the console window To make it pause you must turn on primitive stepping for this robot by sending it the setPause true message You can do this anytime but if you want to step through the entire program do it just after you create the robot Then just before executing any primitive instruction or predicate it will pause and a message will appear in the console window telling you what it is about to do So if your robot is named karel you can use karel setPause true to turn stepping on Then if karel executes a turnLeft instruction it will first display in the system console RobotID 0 is about to turnleft assuming it is the first robot ID 0 you create and will wait for you to type enter return to continue You can also turn off stepping for the robot by sending it the setPause false message It will then behave as usual It will neither print the messages nor wait to continue 7 2 User Stepping You might also want to have the simulator pause elsewhere in your robot program for example at the beginning of the methods that you write yourself This requires two steps You turn pausing on for any given robot by sending that robot the setUserPause true message You can turn it off similarly This alone will have no effect however You must also send the robot userPause do something messages at the points at which you want it to actually pause If you have setUse
15. e File menu You can then Make your project from the Project menu You must correct any errors in your java program and the Make again until there are no more errors You can then Run your project from the Run menu or a button You will need to navigate to the class file in the popup dialog You can simply enter karel KarelMain or whatever the name of your file is If you want to change the main for a project once you have set it select Configurations from the Run menu 2 7 Other IDEs For other IDEs the general principles are that you need create a project to write a program and you need to add the KarelJRobot jar to your project Some simple IDEs may let you write a program without a project but this probably won t work that way You may also need to teach the system to do something sensible with packages If you get class not found exceptions it is either that the jar file is not correctly installed or your package setup is incorrect 3 Access to the World 3 1Building Worlds Run the WorldBuilder in the jar file itself java cp KarelJRobot jar kareltherobot WorldBuilder The world builder will run showing both the world and the world builder dialog See the figure below On many systems double clicking on the KarelJRobot jar file should launch the world builder Page 9 Karel J Robot Simulator User s Guide In a robot program you can open the world builder by creating a new one WorldBuilder builder new WorldBuild
16. er true If the parameter is true as here the speed dialog will also be shown The speed dialog is independent of the world builder but has a way to speed up slow down robot execution as well as pause the action only of multi threaded robots Pick up a tool in the tools button panel The name of the current tool is highlighted Click where you want to place an item controlled by that tool For beepers click near an intersection when using the beeper tool The intersection will be shown in the world builder dialog when you hover the mouse near the corner For walls click across streets for vertical walls and across avenues for horizontal walls when using the corresponding tool Likewise the location at which the wall will be placed will appear in the dialog To put more than one beeper on a corner click more than once with the beeper tool active To lower the number of beepers on a corner control click the corner with the beeper tool On the Macintosh use option click instead of control click To put an infinite number of beepers on a corner control click with the beeper tool when there are none on the corner On the Macintosh use option click instead of control click To clear all the beepers from a corner shift click the corner when using the beeper tool To remove a wall from across a street control click the wall segment with the appropriate wall tool On the Macintosh use option click instead of control click
17. estl If your class is in a package don t forget to prefix the name of your class with its package name For example if you put your code into package karel then the full class name is karel Test1 If you give the classname in the above there are two additional options you can give An option begins with either a or a character immediately followed by b or w upper case accepted also Page 15 Karel J Robot Simulator User s Guide A b option b or b will cause the world builder to be shown along with a speed dialog If you give the w option you then leave a space and give the name of a world file to load for the first run For example w stairworld kwld After the task will is run you will be prompted at the end to ask if you want to run it again without restarting The prompt appears on System out Any response that does not begin with the letter n or N will be treated as a yes even just a return The task then be re executed including any world setup commands There are two sample such test programs packaged in the distribution zip The prompt given is Run robot task Y n c w The first letter of your reply determines what is done If you type just a return the default Y will be taken If you type anything that begins with y or Y the task will be run A response beginning with n or N halts the program If your response begins with c or C the world will be cleared of all elements walls beepers robots before it is
18. h a system You can also set the delay with a slider in the speed dialog You can make this dialog visible by telling the world World showSpeedControl true Note that the pause start button only works when your robots run in threads since they control the threads not the robots If we were to pause the thread in a program that only has one we couldn t start it up again the dialog itself would be running in a paused thread so for simple execution of robot programs this button has no effect Page 22 Karel J Robot Simulator User s Guide You can make a robot named karel sleep for a bit with karel sleep The robot will sleep for a time dependent on the delay time that you set in the program or with the slider The robot s thread will also yield to other threads when this happens 10 3 Miscellaneous By default the robots print traces of their behavior on System out You can turn this on and off with the command World setTrace boolean on At any time you can send a robot its showState String s message and it will print its current state on System out The string will prepend the normal output Normally your main function will want to create robots It is usually necessary for the class that contains this main to either extend some robot class such as UrRobot or to implement Directions Otherwise North for example becomes Directions North The size of the visible portion of the world can be set with World setSize int
19. is to work of course You can also change the color of the beepers and the walls World setBeeperColor Color magenta World setNeutroniumColor Color green darker will set the beepers to magenta and the walls made of Neutronium to a dark green You can now give any robot a small color badge that it will wear If you have several robots in your world you can give them different color badges to keep them separate visually If you have imported java awt Color you can create an UrRobot with a blue badge with UrRobot karel new UrRobot 1 1 North 0 Color blue You will need to implement a constructor in your own classes to make this available to them of course class StairClimber extends UrRobot public StairClimber int street int avenue Direction direction int beepers Color badge super street avenue direction beepers badge You may set the background color of the world with World setWorldColor Color color See the Java Docs Note that the colors you can now set such as this one as well as walls etc are not saved in the world files They are just a feature of the current run The world file definition is unchanged 10 2 Speed You can set the speed of robot execution from the program by telling the world World setDelay int howMuch The delay can range from 0 fast to 100 very slow On some systems a delay of 1 is faster than 0 due to a bug int the thread manager on suc
20. ite easily this way In order to coordinate action in a more complex case however you need to read more of Chapter 8 To run treaaded robots you need the speed controller since the threads startup all paused and you need to resume them before anything happens The speed controller does this as well as set the speed at which they run See Speed under Additional Features in this document for how to make it visible 9 Test Driven Development 9 1 JUnit Testing A modern technique for developing programs is called Test Driven Development in which tests are written before the code is The sound bite is No code without a failing test The simulator supports this by providing a class KJRTest that extends JUnit s TestCase class This class allows you to make assertions about the state of robots and the world It is interesting that while you cannot ask a robot where it is you can assert where it is Complete details may be found online at http csis pace edu bergin KarelJava2ed testInfected 9 2 KarelFixture Also useful for testing is another program not part of the distribution called KarelFixture It permits you to exercise robots without a main without regular programming actually as well as make assertions KarelFixture is keyed to a special tool called Fitnesse http fitnesse org which also provides a wiki that you might find useful You can learn more at http dps csis pace edu 8077 KarelFixture In particular you can
21. l it according to the directions Before you open BlueJ create a text file named Rarel tmpl with a text editor The contents of the file should be exactly SPKGLINE import kareltherobot author date ae public class SCLASSNAME extends UrRobot public SCLASSNAME int street int avenue Direction direction int beepers super street avenue direction beepers Save this file and put a copy into your BlueJ library folder at BlueJ gt lib gt english gt templates gt newclass On the PC this should be easy On the Macintosh OSX it is a bit harder as you need to open the BlueJ package by right clicking on the BlueJ icon and selecting Show Package Contents from the popup The path in the resulting window is a bit different from the above Contents gt Resources gt Java gt english gt templates gt newclass Thanks to Dave Wittry of Troy Highschool in Fullerton CA for this tip You can also make the Karel J Robot JavaDocs available within BlueJ To do this Find the file bluej defs in the lib folder On the Macintosh OSX you must again Show Package Contents for the BlueJ application From there the path is Contents gt Resources gt Java In that file find the section that describes the help system Just after it add the following lines luej help items Rarel b bluej help karel label Karel J Robot bluej help Xarel url c myjavastuff RJRDocs index html You wil
22. l need to supply your own url path to the KJRDocs index file of course Note that the slash is forward On the Macintosh you can start with your own home directory if the KJRDocs are there rather than the system root Once you do this you will see a Karel J Robot item in the BlueJ Help menu that will bring up the JavaDocs for KJR in your default browser Page 3 Karel J Robot Simulator User s Guide Once you have tailored BlueJ for Karel J Robot do the following 1 Open BlueJ and create a new BlueJ project from File menu I named mine karel but that doesn t matter much 2 In BlueJ select Tools Preferences Libraries Select Add and add the file KarelJRobot jar from your Karel installation as a user library to BlueJ Quit and restart BlueJ BlueJ now knows the Karel J Robot classes and you can refer to them 3 Create a package if you like It will give you an new package icon which you can enter by double clicking on it In your new karel project within the package of you like click the New Class button You will get a dialog Give the class a name and select Karel in the list of bullets Click OK You should now have an icon with the name of your class If you double click this icon you can edit the file 4 Notice that your file has import kareltherobot at the top of the class and it extends UrRobot You may need to change the parent class It also has one necessary constructor that you can edit as needed If
23. m may consist of many files A project contains all the necessary files and it manages the compiling and running of your code itself Create a directory folder in which to put the files from the distribution Unzip the distribution file here Your project files can be in this directory or anywhere else you like To get started on a new program project open Codewarrior and select New from the File menu Select Java Stationery in the dialog and give your project a name You can navigate to the location in which you want the new folder to be created Codewarrior likes to create a new folder for your project In the next dialog you can select Java 1 1 or other but this is sufficient and then Java Application or applet if that is what you want CW will create a new project window for you that contains listings of all your files If your system supports Drag and Drop then drag the KarelJRobot jar file to this window Otherwise select Add Files from the Project menu and add it that way Add any other files you want to the project similarly If drag and drop works you may also be able to drag from one project window to another In addition to the window CW has created a new folder for you as suggested above On a Macintosh OS 9 you may need to put the four supplied gif files into that folder Otherwise I don t think you will need them there are copies in the jar actually Page 7 Karel J Robot Simulator User s Guide CW has also added a file
24. n be found without a path CW has a feature on the Macintosh OS 9 that can be irritating If you import a world from another system it won t have its internal type and creator set In fact it won t even have a resource fork If the file s type isn t TEXT the CW won t open it so you can t read it If you open it in another editor that isn t so fussy BB Edit say or QUED you should be able to save it to have its type changed to TEXT so that CW can open it Note that you don t change the EXTENSION of the file That has no effect on the Macintosh You need to change its internal type The same is true if you use the world builder to create a world file Java applications don t set the file s type so you need to do this some other way if you think you need to The extension can stay kwld or anything you like The restrictions mentioned above for OS 9 do not apply to OS X or to other systems Note that some versions of Codewarrior seem to require that the Direction class which defines the actual values of North South etc be referred to by Directions Direction instead of just Direction If you get a class not found error on kareltherobot Direction try this substitution The error message should also point you to the line that needs the change 2 6 JBuilder JBuilder http www borland com jbuilder is a Java environment that is inexpensive or free for education It runs on many platforms Windows Macintosh OS X and unix To use it you
25. nages the compiling and running of your code itself Create a working directory for yourself and put the files extracted from the distribution zip file there This is the same as developing a working directory in the first section of this chapter Your java and karel world files belong here JCreator uses workspaces as well as projects A workspace is a set of related projects You can have one workspace for all your Karel J Robot projects for example Create a new project from the Project menu Select the Basic Java Application icon or Applet if you prefer and give it a name For a location you can fill in or browse to any directory I suggest that you browse to the working directory mentioned above and then fill in a name for your project The project files will be put in a folder named for your project within the working directory so all will be easy to find and manage Say you call it TestProject JCreator will also create a file with the name of your project and add it to the project TestProject java You can either discard this file right mouse button or edit it if you like It will have a package statement that you will want to change probably to karel You can add Page 6 Karel J Robot Simulator User s Guide other files to the project by right clicking on the project icon itself in the left pane or selecting Add Files from the Project menu You need to make JCreator aware of the KarelJRobot jar file to do this selec
26. numberOfStreets int numberOfAvenues The world is still conceptually infinite in two directions This only affects how much is shown A robot might walk outside this region while a program runs and later return to it or not Actually there are about four billion 2 streets and the same number of avenues Not infinite but large The robots now scale in size as you change the window size and or the number of streets This might help if you project a screen for students At the present time scaling causes robots to occasionally disappear briefly There is an alternate version of World setVisible that also has the dimensions of the window pixels in which to show the world This is independent of World setSize mentioned just above Page 23
27. of the default options It should install properly without additional steps that were needed in the past You will also need an editor that is capable of creating plain text files On the PC notepad is not recommended but others will serve I suggest you don t use Microsoft Word for this though WordPad works fine When you write robot programs the extension needs to be java and some editors like notepad really only like the extension to be txt so you might think you have StairClimber java but really have StairClimber java txt It won t work if this happens On your system establish a working directory for yourself It should not be within the distribution directory of the JDK In particular it should not be in the bin directory of that distribution That is always a dangerous practice and can defeat the security arrangements of Java You should create a new directory folder using system commands If you work on a PC it might be something like c JavaProjects You can do everything within this directory If you put your robot code into packages then one directory is enough and the compiler will create others for you as needed The KarelJRobot jar file that contains the simulator should be in this working directory If you use the Test Driven Development subsystem then junit jar belongs here also Page 1 Karel J Robot Simulator User s Guide There are two things you need to do to use the system You need to compile your code with the java
28. op Type the initial part of a class name here and it will show all of the possibilities that begin that way Back on the Class naming dialog don t forget to fill in any needed interfaces You can browse for these also kareltherobot Directions is frequently needed BTW Enclosing type is for creating inner classes The three check boxes at the bottom let you add a main automatically if your class needs one as well as putting in stubs for inherited abstract methods and superclass constructors This is helpful for robot classes of course where you need the constructors Once you have your Java files you can build from the Project menu and run from the Run menu Errors are shown in the Tasks pane at the bottom which becomes the Console when you are actually running The Run menu will also let you set command line parameters for an execution Eclipse has many other options Window Menu including one to automatically build when you save a file It also integrates nicely with the JUnit testing framework mentioned below You can find the project preferences by right clicking on the project icon in the left pane The preferences option is at the bottom of the popup 2 4 JCreator PC Only JCreator http www jcreator com is a simple but relatively complete inexpensive Java IDE that runs on Windows To use it you create a project for each program though a program may consist of many files A project contains all the necessary files and it ma
29. package into a class in another package or at least I haven t figured out how Note that a flaw in BlueJ exposes some of our implementation details to the student There is a lot of stuff hidden in our simulator that should not be so exposed being fixed BlueJ also integrates with the JUnit testing framework discussed below 2 3 Eclipse Eclipse is a professional free and open source development environment with many capabilities It is written in Java and so runs nearly everywhere except Mac OS 9 To use Eclipse you must create a project for each program though a program may consist of many files A project contains all the necessary files and it manages the compiling and running of your code itself 1 Download and install Eclipse from the web site http eclipse org Eclipse manages its own files and will make copies of the files in the download directory as necessary Unzip the karel distribution file in a place of your choice and then open Eclipse The Left Hand pane of the window should show the Hierarchy View Right click in this pane and select New gt Project Select Java Project in the dialog and then click Next Give your project a name say StairClimberProject If you want to also use the Test Driven Development framework click Next again otherwise click Finish To use Test Driven Development click the Libraries tab and then the Add External Jars button Navigate to the plugins directory of your Eclipse installation and
30. rPause true earlier in the program then the robot will write the string you include as a parameter into the console window and will wait for you to type a return enter Actually the string will be prepended with RobotID x is about to so with the example message above sent to karel the console will actually show RobotID 0 is about to do something Use this information to make your strings informative The usual way to use this is to put userPause messages at the beginning of your methods For example public void turnRight userPause turn right turnLeft turnLeft turnLeft Here the message goes to the this robot of course just as the turnLeft messages do Page 19 Karel J Robot Simulator User s Guide Note that by itself userPause does nothing unless you turn on user pausing for that robot This way you can leave userPause messages in your programs and then have them pause or not at these points by turning user pausing on or off with setUserPause true and setUserPause false Note finally that you can turn on both Primitive stepping and User stepping These are independent of each other 8 Threaded Robots You can run robots in several threads This is discussed in Chapter 8 of the book but can be used earlier with only a couple of tools The first two sections of Chapter 8 are quite simple and explain all you need to make it happen You could do a multiple robot harvesting task qu
31. rameter is always optional You will need a main or a task see the next section If you write a main you can put it into one of your robot classes or into one by itself public in a separate file Main functions need to be in a public class to be useful If you use a separate class recommended it doesn t extend any robot class and therefore must implement the Directions interface if you want to use the direction names or infinity within the main method You can give world commands as well as create and exercise robots in the main I usually separate the world commands from the main however into a static block A static block is an anonymous method that is automatically executed when the class that contains it is loaded static World setDelay 1 World readWorld worlds stairworld kwld World setVisible true World showSpeedControl true However if you write a robot class that you intend to use as a superclass of other classes like the supplied AugmentedRobot java then you should not use a static block there as it will be executed whenever you create a robot in any subclass of this one because the superclass must be loaded also 5 Options for Running main vs task 5 1 main In Java any public class can have a main method and any of these can begin the execution of a task from the operating system Usually main is very small It creates a few objects and sends a Page 14 Karel J Robot Simulator User
32. s Guide message or two and the objects do the real work Chapter 2 of the text shows many examples of main methods The form is required by Java and must be strictly adhered to Even IDEs like BlueJ that let you avoid main still have one though it is hidden from the user When you issue a java command from the command line you always name a class that contains such a main method 5 2 task If you want to avoid the ugliness of main there is another option supported by Karel J Robot Build a new in package kareltherobot Your class must implements the RobotTask interface This extends Directions so you don t need to implement both Give this new class a method with protocol public void task Put all of your robot commands and any world commands inside this task method Here is an example import kareltherobot class Testl implements RobotTask public void task World readWorld box kwld UrRobot karel new UrRobot 3 3 East infinity karel turnLeft karel move karel turnLeft karel move karel turnLeft karel move karel turnOff The RobotTask interface requires only this one method Now run your program with either of the following commands java cp KarelJRobot jar kareltherobot KarelRunner Testl or java cp KarelJRobot jar kareltherobot KarelRunner In the last case you will be prompted for the name of the class and you can respond T
33. t Project Settings from the Project menu and click the Required Libraries tab Click New and then type a name Karel into the top field and click Add Add package and navigate to the jar file and select it and click Open Then OK Finally make sure the little box next to the thing you just created Karel is checked and click OK again Phew Now you can build your project There are buttons for this but you can also do it from the Build menu or use F7 Before you can run however you need to put a copy of KarelJRobot jar into the project directory It needs to be both in the project itself AND in the project directory Not ideal but I haven t found a shortcut Next you need to tell JCreator which file is your main file When you Execute Project F5 from the Build menu you will get a dialog Use it to navigate to the class file of your main This should be below your project directory in a directory called classes and further in a subdirectory named for your package karel Perhaps it is KarelMain class in this directory Select it to run 2 5 CodeWarrior Codewarrior http www metrowerks com is a professional quality development environment that is inexpensive for education and very complete It runs on many platforms and supports many languages If you want to do Java on Macintosh OS 9 this is about your only choice except for the online version in the JJ system To use CW you create a project for each program though a progra
34. t is written in Java 1 1 using AWT it uses the look and feel of your platform This is an older figure It now has a button to show hide the speed dialog World builder shows the position of the mouse in street avenue coordinates if you have selected any tool If the current tool is the Beeper tool it shows the nearest corner where the beeper will be placed if you click If the current tool is the Horizontal Wall tool it shows where the corner below the wall that will be placed If the current tool is the Vertical Wall tool it shows the corner to the left of the wall that will be placed You can also create a world using program statements by sending messages to the World You may then save them with the saveWorld command See the JavaDocs The basic options are World placeBeepers int street int avenue int howmany World placeEWWall int NorthofStreet int atAvenue int lengthTowardEast World placeNSWall int atStreet int EastOfAvenue int lengthTowardNorth World saveWorld String filename Page 11 Karel J Robot Simulator User s Guide Finally you can run a robot program and save the results including new placements of beepers that occurred as the program ran by saving the world at the end 3 2 Using Worlds Remember the name you used when you saved it Say test kwld Include a statement in your robot program to open it Include this at the beginning of your main task block
35. ues The number of avenues to draw e beepers The data is street avenue number of beepers without punctuation of any kind Page 12 Karel J Robot Simulator User s Guide e eastwestwalls The data is North of Street first avenue crossed last avenue crossed Last should be bigger than first or equal e northsouthwalls The data is East of Avenue first street crossed last street crossed Last should be bigger than first or equal The world builder writes out a separate wall command for each segment of a wall one block long If you do it by hand you can combine them and create long walls in one command If you create a world in a Robot program using the programming interface and save it it will be consistent with the world builder files You can erase everything including robots in a world with World reset 4 Writing Your Robot Classes When you write robot code you need to include a few things in your classes I recommend that you put your code into a package of your own naming The package statement must come first in your program I don t recommend you use the kareltherobot package that contains the simulator itself but a karel package is fine package karel Next should come your imports You probably want to import everything in the kareltherobot package import kareltherobot In many ways it is better to import individual classes rather than the above In this case you often need something like
36. you created the file inside a package it will also have the package header 5 Copy any world file such as test kwld from the original download directory into the new Rarel project directory 6 When your class is complete compile and run When you compile you will be guided to fix the errors if any Also in BlueJ you need a way to get the world to show and to otherwise manipulate the world itself I suggest that you create an Initializer class and give it to your students for modification It should be in whatever package your students build in It will therefore be visible in the BlueJ main design pane and you can send the initializeWorld message by clicking as usual Modify this to manipulate the World public class Initializer public static void initializeWorld kareltherobot World setSize 12 12 kareltherobot World setDelay 50 kareltherobot World readWorld folder worldfile kareltherobot World showSpeedControl true See the JavaDocs for class World for more options builder new kareltherobot WorldBuilder true Page 4 Karel J Robot Simulator User s Guide kareltherobot World setVisible true static kareltherobot WorldBuilder builder null It is strongly recommended that you put all your code into a package other than the default unnamed package It can have your own name for example The default package is discouraged in Java You cannot import a class defined in the default
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