A library in support of Java: Learning to Program with Robots, an introductory Java programming textbook by Byron Weber Becker; see also the Required Programming Skills for projects in the xtras package and the Change Log for the entire library.

See:
Description

Packages

becker.gui	Classes to help create graphical user interfaces.
becker.robots	Karel the Robot provides a gentle introduction to object-oriented programming via a simple robot which can move, turn left, pick things up, transport them and put them down again.
becker.robots.icons	Icons used to display robots, intersections, and other things in the robot world.
becker.util	Provides generally useful utilities for beginning programmers.
becker.xtras.comboLock	The comboLock package provides a graphical user interface (GUI) for a combination lock that uses an instance of a student-written class implementing the IComboLock interface.
becker.xtras.gasPump	The gasPump package provides a graphical user interface (GUI) for a gas pump that uses three instances of a student-written class implementing the IMeter interface.
becker.xtras.grapher	The grapher package provides a graphical user interface to graph mathematical functions which implement one of three Java interfaces: IFunction, IQuadraticFunction, or IPolynomialFunction.
becker.xtras.hangman	Provides a graphical user interface (GUI) for a game of Hangman that uses an instance of a student-written class implementing the IHangman interface.
becker.xtras.imageTransformation	The imageTransformation package provides a graphical user interface (GUI) for a student-written class to transform images using a two-dimensional array of integers.
becker.xtras.jotto	Jotto is a game program where students may contribute some of the code.
becker.xtras.marks	Provides a graphical user interface (GUI) for a student-written class to maintain assignment marks in a two-dimensional array.
becker.xtras.nameSurfer	NameSurfer graphs names and their popularity over time as gathered from United States Social Security Administration data.
becker.xtras.radio	Provides a graphical user interface (GUI) for an AM/FM radio using two instances of a student-written class implementing the ITuner interface.
becker.xtras.tollBooth	The tollBooth package provides a graphical user interface (GUI) for a highway toll booth simulation that uses an instance of a student-written class implementing the ITollBooth interface.

A library in support of Java: Learning to Program with Robots, an introductory Java programming textbook by Byron Weber Becker; see also the Required Programming Skills for projects in the xtras package and the Change Log for the entire library.

Required Programming Skills

The becker.xtras packages include code designed to be used in assignments. Each sub-package includes a graphical user interface that works with one or more instances of a class or classes written by students (generally the model part of the model-view-controller pattern). Classes written by students are always specified by an interface.

The following table summarizes the programming skills each project is designed to exercise.

Key:

^	Designed to increase skill in this area
•	Required competency
+	Optional

Package

Using Objects

Inheritance

Instance Variables

1D Arrays

GUIs

Using Multiple Instances

Control Structures

Collaborative Classes

2D Arrays

Writing Methods

Parameters

I/O

Polymor.

robots (Level 1)

^

^

robots (Level 2)

•

•

^

^

^

robots (Level 3)

•

•

•

•

•

^

^

+

+

comboLock

(10-20-30)

•

^

•

^

gasPump

•

^

^

•

^

radio

•

^

^

+

•

^

+

grapher

•

•

•

^

+

nameSurfer

•

•

•

•

•

^

^

^

+

hangman

•

•

•

•

•

•

^

+

•

+

+

imageTransformation

•

•

•

•

•

^

jotto

•

•

•

+

•

•

•

^

^

^

+

marks

•

•

•

•

•

•

•

^

Skills Summary

• Using Objects: Using interesting objects created from provided classes.
• Using Multiple Instances: Using multiple instances of a class to drive home that they really are independent.
• Writing Methods: Writing a class that contains methods.
• Inheritance: Extending a class and using the features of the superclass.
• Control Structures: Using control structures such as selection and repetition.
• Parameters: Writing methods that use parameters.
• Instance Variables: Writing classes that use primitive instance variables.
• Collaborative Classes: Writing classes that use composition, pass objects as parameters, and return them from methods.
• I/O: Writing classes that read and write files.
• 1D Arrays: Writing classes that use 1D arrays or a collections object.
• 2D Arrays: Writing classes that use 2D arrays.
• Polymorphism: Writing classes that behave polymorphically.
• Graphical User Interfaces: Writing a graphical user interface or a part of an interface.

Becker Library Change Log

2006-06-26

• Added becker.xtras.tollBooth to support lectures for Chapter 07.
• If a City is constructed by reading a file, the class now shows a JFileChooser, allowing the user to easily choose an input file.
• Fixed a bug related to resizing a custom icon when a robot picks or puts a Thing.
• Fixed a bug when Intersection has an icon that is not IntersectionIcon.

2005-12-14

• Released to production for CD-ROM.
• Added becker.util.AbstractModel to make implementing IModel as painless as possible.
• Changed the daysUntil method in becker.util.DateTime to return an int instead of long.
• Reworked the DateTime.format() method to use constants set by setFormatLength and setFormatInclude instead of passing constants as parameters to format

2005-08-18

• Added setColor and getColor to Icon and Sim, making the ability to color things nearly universal and easy.
• Added a public constructor to becker.util.Test to facilitate using the class before class methods are discussed.
• Removed the deprecated method daysBetween from DateTime.
• Added new documentation to the library's overview documenting the learning objectives of various packages and providing running examples.
• Made most of the student-implemented classes in becker.xtras full-fledged models from the Model-View-Controller pattern.
• Began obscufiating the libraries.

2005-08-02

• JDK1.5 is now required.
• Methods and constructors that take an avenue and a street have had the order of those two parameters switched. For example, new Robot(aCity, aStreet, anAvenue, aDirection)
• Replaced becker.robots.Directions with becker.robot.Direction, an enumerated type.
• Replaced the isBesideThing() method in becker.robots.Robot with canPickupThing(), which better describes the question the method answers.
• Changed City to show itself in a frame. Elimintated CityFrame.
• Moved Icon and subclasses to a subpackage, becker.robots.icons, to reduce the clutter and distractions in the JavaDoc.
• Made Robot a subclass of Sim rather than Thing.
• Replaced examineThing with examineThings, which returns an iterator, giving access to all the things rather than just a random one. Added companion methods examineRobots and examineLights. This applies to Robot, Intersection, and City.
• Renamed getRelativeSize and setRelativeSize in Icon and subclasses. Added setColor, getColor, setTransparency, and getTransparency.
• Added getTransparency and setTransparency to the IColor interface and the classes that implement it.
• Added information to the files read by City#City(Scanner) to specify frame title, streets to display, etc.
• Added MazeCity, an extension of City that builds a maze with walls.
• Removed the followed deprecated classes:
  • becker.robots.Colorable (superceded by IColorable)
  • becker.robots.ColoredIcon (superceded by IColorable)
  • becker.robots.Labeled (superceded by ILabeled)
  • becker.robots.Predicate (superceded by IPredicate)
  • becker.util.FormLayout (superceded by becker.gui.FormLayout)
  • becker.util.RowLayout (superceded by becker.gui.RowLayout)
  • becker.xtras.FormLayout (superceded by becker.gui.FormLayout)
  • becker.xtras.RowLayout (superceded by becker.gui.RowLayout)
  • becker.xtras.LedDisplay (superceded by becker.gui.LedDisplay)
• The book's title will be revised slightly when it is published by Course Technology. The documentation's window title reflects the new title.

2004-12-08

• Added set methods and some static factory methods to DateTime. Now properly overrides hashCode.
• Added the becker.xtras.hangman package.
• Added becker.gui.JIntField.
• Deprecated the interfaces Colored and ColoredIcon and merged them into IColorable.
• Deprecated Predicate and added IPredicate.
• Deprecated Labeled and added ILabel.
• Renamed interfaces in the becker.xtras.grapher package.
• Cleaned up indentation on some code examples in the documentation.
• Made a number of protected methods in Robot public in RobotSE.

2004-11-01

• Fixed a bug in CompositeIcon when used with icons having relativeSize <> 1.0

2004-10-18

• Provide links in the JavaDoc documentation to standard jdk1.4 classes.
• Fixed a bug in Thing(Robot heldBy) where the robot didn't actually end up holding the thing.
• In Robot, isBesideThing(Predicate.anyRobot) always returned true (because the robot is always beside itself), which is unintuitive and has no easy work-around. isBesideThing is implemented in terms of examineThing(Predicate p). Changed examineThing to always explicitly exclude the robot itself.
• Made the variables holding convenience predicates in Predicate final.
• Refactoring in becker.xtras.jotto; improvements to documentation.
• Added a help dialog to Jotto.
• getSpeed() and setSpeed() in Robot were unintuitive expressed as milliseconds per move. To speed things up by a factor you divided and to slow down you multiplied. Changed them to be measured in seconds per move. Now, to go twice as fast, write this.setSpeed(this.getSpeed()*2).

2004-08-30

• Added ckIsBetween(...) methods to becker.util.Test.
• Added documentation for constructing a City from a text file and fixed a bug causing that constructor to hang if the last line did not include a carriage return.

2004-05-27

• Added becker.xtras.gasPump.
• Renamed becker.xtras.comboLock.Demo to DemoComboLock to avoid duplicate names in the JavaDoc listing of all classes. Similarly for the grapher, imageTransformation, marks, and radio packages.
• Fixed a bug in Jotto when no words met the requested hint criteria.
• Improved the documentation for some Jotto classes; added sample hint classes.
• Copied becker.xtras.FormLayout, becker.xtras.RowLayout, and becker.xtras.LedDisplay to becker.gui and deprecated the originals. Last time they move, I promise!

2004-01-30

• Added the becker.xtras.jotto package to support array-based homework assignments.
• Made three methods in becker.robots.Intersection public rather than private: countThings(), countThings(Predicate), and examineThing(Predicate).

2003-11-26

• Increased the size of the buffer in TextInput.
• Moved becker.util.FormLayout and becker.util.RowLayout to becker.xtras.
• Added becker.xtras.LedDisplay to simulate light emitting diode diasplays commonly found on clocks and radios.
• Added becker.xtras.radio, a GUI simulating an AM/FM radio; students provide two instances of the interface ITuner.
• Added sample implementations to packages in becker.xtras so students can easily see an example of what they should implement.

2003-11-19

• Added the AppletRunner class to make it quick and easy to run a robot program as an applet.
• Added preconditions in RobotSE to ensure that parameters to move(int), turnLeft(int), and turnRight(int) are positive.
• Fixed a bug in TextInput where calling skipSpaces twice in a row left the file cursor in a wrong state.
• Added clone and equals to DateTime.

2003-09-20

• Corrected an erroneous example in the Icon class.
• The previous version omitted a word list in becker.xtras.jotto. Fixed.
• Added a daysBetween method to the becker.util.DateTime class.
• Fixed a bug in Test.ckEquals(String, Object, Object) where it did not handle two null objects correctly.

2003-08-25

• Added scrollbars to move around the view of the city.
• Added a zoom control to zoom in and out on the view of the city.

2003-08-13

• Improve animation performance and fix a synchronization bug.
• Removed KarelFrame.
• Added methods to CityFrame to control title, size, and location.
• Renamed RobotsUI to RobotUIComponents and added accessor methods making customized graphical interfaces much easier to build.

2003-07-10

• Correct some javadoc problems.
• Put the constants for Predicates back in the Predicate class rather than distributing them to many classes.
• Fixed a bug in the imageTransformation sample solution that rotates the image.
• Added to constructors that do not require the numThings parameter to RobotRC and RobotSE -- to match the new constructor added to Robot some time ago.

2003-06-13

• Fixed a bug in becker.io.TextInput where readInt sometimes returned the same number twice in a row.

2003-06-09

• Renamed the becker.xtras.imageManipulation package to becker.xtras.imageTransformation to be more consistent with class names. Restructured the ImageTransformerGUI so that extraneous JFrame methods don't show in the JavaDoc. Automatically loads a picture. Added some new transformations.

2003-05-30

• Added the becker.xtras.marks package.

2003-05-26

• Deprecated readWord and wordIsAvailable, replacing them with readToken and tokenIsAvailable due to student confusion over what constitutes a "word".
• Changed readLine so that it skips leading whitespace, making it consistent with all the other readX methods (except readChar). Almost every time the issue has come up in class it is because readLine was doing the wrong thing.