The Program is designed with Three classes:

• com.vinay.programs.TriangleConstants
• com.vinay.programs.Triangles
• com.vinay.test.TriangleTest

Triangles.java

main method

• Used To trigger program execution
• New instance of Triangle class is created here and the method getTriangleTypeBySides(...) triggered with standard input stream.

getTriangleTypeBySides(InputStream is)

Scope: Public Return Type: String - Informs the user about Triangle type based on input received or a validation error message is shown

• The program input is read from keyboard input using Scanner class in this method.
• A float[] array to read the tokens from Scanner. It is instantiated to accomodate three elements for three sides of the triangle
• The Scanner instance is defined using try-with-resources feature from Java7 version. This way we need not duplicate catch block related code with exceptions and this will automatically take care of closing the resources.
• If the try-with-resources catches any exception then we will print the error and the Program will exit.
• the float Array is populated using for loop to read first three numbers entered by the user.
• We will validate the Inputs recieved using validateInputs(...) method which takes the populated float Array.
• The validateInputs(...) returns an enum constant of type Errors and is saved in a variable of the same type.
• If the value Error enum is NO_ERRORS_FOUND then getTriangleType(...) method is called with argument float Array userInput else all other Error enum values received returned are validation related errors and will be returned back to the user for information and program will exit.
• The getTriangleType(...) method will read the float Array elements and determines the type of Triange based on the user input.

validateInputs(float[] userInputArr)

Scope: Public Return Type: Errors enum

• Validates the elements from userInputArr float Array to see if the elements are non-negative numbers and if it makes a triangle.
• If no validation errors are found then an `Error1 enum of type NO_ERRORS_FOUND is returned

getTriangleType(float[] triangleSidesArr)

Scope: Public Called from getTriangleTypeBySides(...) Return Type: _String

We will determine the conditions and return the corresponding enum contant String value back to the Consile/Terminal window informing the user :

2.1.Equilateral: If the element at index 0 is equal to element at index 1 AND If the element at index 1 is equal to the element at index 2 then it is of type Equilateral.

2.2.Isosceles: If the element at index 0 is equal to element at index 1 OR If the element at index 1 is equal to the element at index 2 OR If the element at index 2 is equal to the element at index 0 then it is of type Isosceles.

2.3.Scalene: If the element at index 0 is NOT Equal to element at index 1 AND If the element at index 1 is NOT Equal to the element at index 2 AND If the element at index 2 is NOT Equal to the element at index 0 then it is of type Scalene. This condition need not be checked in the If loop as this could go in the last else block.

TriangleConstants.java

• Constants and enums from this class are used in the main program Triangles.java and JUNIT test cases file TrianglesTests.java

Two Enums defined in this class:

• TriangleType
• Error

TriangleTests.java

• JUnit test cases file containing set of test cases to test the methods from Triangles.java main program. A constant is defined which store the line separator retrieved from System class properties as a String.