hmp54 / Fun-With-Shapes

Programming Assignment 2: Fun With Shapes

COSC 150 - Advanced Programming

• Goals
• Description
• Specification and requirements
• Provided files
• Grading rubric

Goals

In order to complete this assignment, you will need to:

• Understand how class heirarchies and relationships are expressed in UML
  • Create a UML class diagram expressing the relationships used in this assignment
• Understand Java object-oriented-programming
  • Create subclasses of existing Java classes
  • Implement the abstract methods of a parent class
  • Understand the relationship between parent and child constructors

Description

In this assignment you will write a program, named FunWithShapes, which will read a text file describing different geometric shapes, convert these test descriptions into objects, and use the resulting objects to perform basic calculations.

You are provided with source code for several classes to help with this task; namely, the abstract classes ShapeHandler and Shape which you will extend to form several subclasses.

Specification and requirements

Specification

You will implement a class named FunWithShapes whose main method will read in data from a text input file and populate a Vector of Shape objects. Your program will then sum the areas of all shapes and the perimeters of all shapes and print these results to the terminal.

The format of the input file, as well as descriptions of the provided code, are given below.

The input file

Data input for your program is provided by a text file, named shapes.txt, which must be located in your working directly. Each line of this file corresponds to a single geometric shape and will follow one of the patterns below:

• circle <radius> describes a circle with the given radius
• square <sideLength> describes a square with the given side length
• rectangle <height> <width> describes a rectangle of the given dimensions
• triangle <sideA> <sideB> <sideC> describes a triangle of the given dimensions

An example shapes.txt might contain the following four lines:

square 5
rectangle 5 10
square 3
triangle 3 4 5

A valid shapes.txt may have one line or many; it may use a particular shape type multiple times or not at all. Identical data on separate lines should be understood to be two distinct shapes (whose attributes happen to be the same).

The ShapeHandler class

The abstract class ShapeHandler contains the following members:

• Member fields
  • Vector<ShapeDescription> shapeDescriptions stores ShapeDescription objects created by reading and parsing lines of shapes.txt.
  • Vector<Shape> shapes stores Shape-type objects created by parsing ShapeDescriptions.
• Member methods
  • ShapeHandler(), the default constructor, takes the following actions:
    • Opens the shapes.txt file
    • Reads each line of the file
    • Creates a corresponding ShapeDescription and stores it in the shapeDescriptions vector.
    • Calls convertDescriptionsToShapes().
  • convertDescriptionsToShapes(), an abstract method, should:
    • Iterate through shapeDescriptions
    • Instantiate an appropriate Shape-type object and store it in the shapes vector.
  • sumOverAreas(), an abstract method, should:
    • Iterate through shapes
    • Compute a running total of the shape areas and return the result.
  • sumOverPerimeters(), and abstract method, should:
    • Iterate through shapes
    • Compute a running total of the shape perimeters and return the result.

You will implement FunWithShapes to extend this class (and, by extension, implement the abstract methods described above).

The Shape class

The abstract class Shape contains the following member methods:

• Shape( ShapeDescription ), a constructor; subclasses will use the ShapeDescription object to initialize the appropriate member fields. (note: Shape has no default constructor.)
• getArea(), an abstract method which returns this shape's area.
• getPerimeter(), an abstract method which returns this shape's perimeter.

You will implement several subclasses of Shape corresponding to the shape types in shapes.txt with appropriate member fields and method implementations.

The ShapeDescription class

The class ShapeDescription is an intermediate representation of a shape with the following members:

• Member fields:
  • ShapeTypes shapeType, an enumerated value set by parsing the shape from a line of shapes.txt.
  • Vector<Double> doubles a vector of doubles matching those provided in shapes.txt for this shape. The number of values will depend on the shape type.
• Member methods:
  • getShapeType(), which returns the value of shapeType.
  • getDoubles(), which returns the vector doubles.
• Other members:
  • ShapeTypes, an enumerated type with four values:
    • ShapeTypes.CIRCLE
    • ShapeTypes.SQUARE
    • ShapeTypes.RECTANGLE
    • ShapeTypes.TRIANGLE The fully-qualified name for, e.g., the circle type is ShapeDescription.ShapeTypes.CIRCLE (for comparison in main())

The provided code in ShapeHandler will generate these objects by parsing the shapes.txt file; you will use them to generate Shape-type objects.

The ShapeException class

This is a simple Exception-type object which is thrown by ShapeHandler() or ShapeDescription() in response to invalid syntax within shapes.txt or other I/O issues.

Requirements

You will create the following files and add them to your repository:

• ClassDiagram.pdf, a UML class diagram which describes the relationships between all classes used in this project:

  • All provided classes (in the given code)
  • All classes you implement This diagram will be hand-graded by me after the due date; I will use your last commit (before the deadline) when examining this file.

• FunWithShapes.java, implementing the class FunWithShapes. This class should

  • Extend ShapeHandler and implement the abstract methods described above.
  • Provide a main() method which will
    • Instantiate a FunWithShapes object
    • Invoke sumOverAreas() on that object.
    • Invoke sumOverPerimeters() on that object.
    • Print these two values to the terminal (see below).

• Four source files, each implmenting a single subclass of Shape:

  • Circle.java
  • Square.java
  • Rectangle.java
  • Triangle.java

Program invocation and outputs

Your program will be executed by running the FunWithShapes class. It should output exactly two lines to the terminal.

• The first line should contain ONLY the sum of the areas of all shapes (i.e., the return value of sumOverAreas())
• The second line should contain ONLY the sum of the perimeters of all shapes (i.e., the return value of sumOverPerimeters()) Your program should not produce ANY additional output (no line labels, units, etc). Doing so will cause the test script to incorrectly parse your output as non-numeric and the test will fail.

As an example, invoking your program on the sample shapes.txt above would produce the following output in terminal:

$ java FunWithShapes
90.0
74.0

Provided files

The following files are provided code for the project and already present in your repository:

• ShapeHandler.java
• Shape.java
• ShapeDescription.java
• ShapeException.java

You should not modify these files while implementing your code; doing so may cause the autograding tests to fail.

Additionally, the following files related to project logistics are present in your repository:

• README.md which provides this specification.
• .gitignore which specifies files git should NOT track.
  • Note that shapes.txt is specifically listed so it will NOT be added to tracking.
• .travis.yml which provides instructions to trigger Travis testing.
• travis a directory containing the testing scripts.

You should not modify any of these files while working on your project; doing so may break Travis such that a test build does not run, or gives false/misleading feedback about your code.

Grading rubric

Your score for this assignment is determined according to the following rubric.

Amazing Feat	Points Awarded	Tested by TravisCI?
Travis-graded tests
Your repository contains at least one commit.	10	Yes
Your commit contains all the required files with correct names.	10	Yes
Your source code compiles.	20	Yes
Your Circle class instantiates; correcly computes area, and correctly computes perimeter.	15	Yes
Your Square class instantiates; correcly computes area, and correctly computes perimeter.	15	Yes
Your Rectangle class instantiates; correcly computes area, and correctly computes perimeter.	15	Yes
Your Triangle class instantiates; correcly computes area, and correctly computes perimeter.	15	Yes
The total area and perimeter reported are correct (30x random files)	30	Yes
Ray-graded tests
Your class diagram is legible, neatly formatted, and uses proper UML styling for classes and relationships.	20	No
Total points	150