Thomas Banks

Well spotted Martin. I have made the changes. Thank you

What I have done is create two Triangle constructors, one which will take string parameters (two many/few parameters) and one that will take integers and calls the validate method(calculate triangle <=0,>500,s1 > s2 +s3 ect).
I don't know if that's good practice(probably not?) but since the assignment is about writing my test cases first and then writing product code to make them pass I'm not too bothered so long as they pass, and they do. This is also why I throw a valid triangle exception so my test can pass for 3 valid parameters. Basically, my lecturer whats all my test cases to pass!

The very first problem I had when I started this thread (non-integer exception) is now working 100% with the string split method so thanks for that.

I still have a problem, in calling the validate method in my integer constructor I seem to upset the sides I have initialized to calculate the area. Is there something I could do to make them work in harmony?
This is what my constructor looks like and the area and validation tests that get in each others way.

public Triangle(int side1, int side2, int side3) throws TriangleException{ //they don't get along very well this.side1=side1; this.side2=side2; this.side3=side3; Triangle.validate(side1, side2, side3); }

Oh and I limited it because I didn't want big ridiculous triangles.

public void test01Area() throws Exception { Triangle t = new Triangle(50,50,50); assertEquals(t.getArea(),1082.53); } public void test01() throws Exception { try { Triangle t = new Triangle(20,30,40); fail("Exception Expected – Should not Get HERE!"); } catch (TriangleException te) { assertEquals("valid triangle", te.getMessage()); } }

I have amended the code in my constructor to the way you recommended and I my valid and invalid triangle integer tests are passing. I also wrote some code to calculate the area
of the triangle and it worked but after creating the if statement to throw the exceptions (valid and invalid triangle) it no longer worked. How would I get my area test to pass again?
Since I enforced the invariant's for a triangle in the constructor what good are my setxxx methods and how should I re-write them?

Also, the validate method will still take string parameters how can I call that method from my constructor or any other method for that matter and also how would I create a test case if the triangle is now of integer type.
I have included all my product code and some of my tests. I have made a go at the validate method and tried to use the string split method but i think its not fully correct yet.

Thanks for your help

import java.text.DecimalFormat; import java.util.Scanner; import java.util.StringTokenizer; public class Triangle { // Represent the 3 sides of a triangle private static int side1; private static int side2; private static int side3; public Triangle(int side1,int side2,int side3) throws TriangleException { //this.side1 = side1; //this.side2 = side2; //this.side3 = side3; if (side1 + side2 >= side3 && side2 + side3 >= side1 && side1 + side3 >= side2 && side1 > 0 && side2 > 0 && side3 > 0 && side1 < 500 && side2 < 500 && side3 <500){ throw new TriangleException("Valid Triangle"); }else { throw new TriangleException("Invalid Triangle"); } } protected static void validate(String parameters) throws TriangleException { String str = parameters; String[] sides = str.split(","); for(int i=0;i<sides.length;i++) { int myVal = Integer.parseInt(sides[i]); if (i > 2) throw new TriangleException("Invalid Triangle: Too many parameters"); //sides[i] = Integer.(); else if (i < 0) { throw new TriangleException("Invalid Triangle: No integers detected"); } } //this code does not work if (sides[0] == 0 || sides[1] == 0 || sides[2] == 0) { throw new TriangleException("Invalid Triangle: Not enough integers input"); } else if (sides[0] < 0 || sides[1] < 0 || sides[2] < 0) { throw new TriangleException("Invalid Triangle: Negitive parameter"); } else if (sides[0] > sides[1] + sides[2] || sides[1] > sides[0] + sides[2] || sides[2] > sides[0] + sides[1]) { throw new TriangleException("Invalid Triangle: One parameter is greater than the sum of Two parameters"); } else if (sides[0] > 500 || sides[1] > 500 || sides[2] > 500) { throw new TriangleException("Invalid Triangle: One or more parameter is outside the valid range(1-500) of a triangle"); } else { throw new TriangleException("Valid Triangle"); } } catch (NumberFormatException nfe) { throw new TriangleException("Invalid Triangle: Parameter is not an integer"); } } public int getside1() { return side1; } public void setside1(int value) throws TriangleException { if (value <= 0) { throw new TriangleException("Input Invalid: One side is less than or equal to 0"); } else if (value > 500) { throw new TriangleException("Input Invalid: One side is greater than 500"); } else if (value > side2 + side3) { throw new TriangleException("Input Invalid: One side is greater than the sum of two sides"); } else side1 = value; return; } public int getside2() { return side2; } public void setside2(int value) throws TriangleException { if (value <= 0) { throw new TriangleException("Input Invalid: One side less than or equal to 0"); } else if (value > 500) { throw new TriangleException("Input Invalid: One side is greater than 500"); } else if (value > side1 + side3) { throw new TriangleException("Input Invalid: One side is greater than the sum of two sides"); } else side2 = value; return; } public int getside3() { return side3; } public void setside3(int value) throws TriangleException { if (value <= 0) { throw new TriangleException("Input Invalid: One side less than or equal to 0"); } else if (value > 500) { throw new TriangleException("Input Invalid: One side is greater than 500"); } else if (value > side1 + side2) { throw new TriangleException("Input Invalid: One side is greater than the sum of two sides"); } else side3 = value; return; } public double getArea() { double s, area; s = (side1 + side2 + side3) / 2.0; area = Math.sqrt(s * (s - side1) * (s - side2) * (s - side3)); DecimalFormat decim = new DecimalFormat("0.00"); double area2 = Double.parseDouble(decim.format(area)); System.out.println(+area); return area2; } }

//pass public void test01TriangleCreation() throws Exception { try { Triangle t = new Triangle(10,10,10); fail("Exception Expected – Should not Get HERE!"); } catch (TriangleException te) { assertEquals("Valid Triangle", te.getMessage()); } } //pass public void test02TriangleCreation() throws Exception { // Place Test Description Here try { Triangle t = new Triangle(10,100,10); fail("Exception Expected – Should not Get HERE!"); }catch (TriangleException te){ assertEquals("Invalid Triangle", te.getMessage()); } } //fail public void test03Area() throws Exception { Triangle t = new Triangle(50,50,50); assertEquals(t.getArea(),1082.53); }

Thank you for them steps.
My lecturer however, does not want us to edit his code (skeleton code with empty methods that compiles but does nothing) in anyway.
The assignment is to show our knowledge of the software development process, write test cases first then get the tests to pass by writing our own product code.
The code I have shown is just one part of the assignment as I have to get the area and do individual tests on the 3 sides. I will post the skeleton code below so you know what I am talking about.

He did include the string tokenizer class so I assume he wanted us to use it but I was not familiar with it at all, someone recommended I use the scanner class instead.
Is there fundamental problems with my code? Other than the fact I cant throw an exception if a string is entered because it has taken me quite a bit of time to get this far.

thanks

import java.util.StringTokenizer; public class Triangle { // Represent the 3 sides of a triangle private int side1; private int side2; private int side3; public Triangle(String parameters) throws TriangleException { // This method accepts as input the three integers that // represent a triangle. The numbers, separated by a // comma, are inputted as a string. // This method validates that the integers can form a // valid triangle and assigns the values to side1, // side2, and side3. } protected static void validate(String parameters) throws TriangleException { // This method validates that three integers form // a valid triangle. The numbers, separated by a // comma, are inputted as a string. // If there are no integers, insufficient integers, or // too many integers inputted , the method throws a // TriangleException with a meaningful message. // If non-integer data is inputted, the method throws a // TriangleException with a meaningful message. // If the integer values are invalid, the method throws a // TriangleException with a meaningful message. } public int getside1() { return side1; } public void setside1(int value) throws TriangleException { // This method validates and sets side1 value. // The method throws an exception if the side1 // value is invalid. } public int getside2() { return side2; } public void setside2(int value) throws TriangleException { // This method validates and sets side2 value. // The method throws an exception if the side2 // value is invalid. } public int getside3() { return side3; } public void setside3(int value) throws TriangleException { // This method validates and sets side3 value. // The method throws an exception if the side3 // value is invalid. } public double getArea() { // This method calculates the area of the triangle // using side1, side2, and side3. } }

The program I am creating is part of a college assignment.
My lecturer wants the numbers inputted as a string separated by a comma for reasons unknown, probably to make it 10 times tougher.

This is my full code. To be honest I'm not sure if the parameters are being read into the sides of the array myself but it seems to be working.
There is Comparison failure coming up and I think the two test are confusing each other. I have included that other test case which I suppose to find no integers.

import java.util.Scanner; import java.util.StringTokenizer; public class Triangle { private static int side1; private static int side2; private static int side3; // private double area; public Triangle(String parameters) throws TriangleException { Scanner scanner = new Scanner(parameters).useDelimiter(","); try { int[] sides = new int[3]; for (int i = 0; i < 4; i++) { if (scanner.hasNextInt()) { if (i > 2) throw new TriangleException("Invalid Triangle: Too many parameters"); sides[i] = scanner.nextInt(); } else if (i == 0) { throw new TriangleException("Invalid Triangle: No integers detected"); } } if (sides[0] == 0 || sides[1] == 0 || sides[2] == 0) { throw new TriangleException("Invalid Triangle: Not enough integers input"); } else if (sides[0] < 0 || sides[1] < 0 || sides[2] < 0) { throw new TriangleException("Invalid Triangle: Negitive parameter"); } else if (sides[0] > sides[1] + sides[2] || sides[1] > sides[0] + sides[2] || sides[2] > sides[0] + sides[1]) { throw new TriangleException("Invalid Triangle: One parameter is greater than the sum of Two parameters"); } else if (sides[0] > 500 || sides[1] > 500 || sides[2] > 500) { throw new TriangleException("Invalid Triangle: One or more parameter is outside the valid range(1-500) of a triangle"); } else { throw new TriangleException("Valid Triangle"); } } catch (NumberFormatException nfe) { throw new TriangleException("Invalid Triangle: Parameter is not an integer"); } }

public void test07NonIntegerData() throws Exception { try { //Test to see if a triangle can be created Triangle t = new Triangle("one,two,three"); fail("Exception Expected – Should not Get HERE!"); } catch (TriangleException te) { assertEquals("Invalid Triangle: Parameter is not an integer", te.getMessage()); } } public void test03TriangleNoParameters() throws Exception { try { //Test to see if a triangle can be created Triangle t = new Triangle(""); fail("Exception Expected – Should not Get HERE!"); } catch (TriangleException te) { assertEquals("Invalid Triangle: No integers detected", te.getMessage()); } }

And a picture paints a thousand words so I have attached one.
Thanks

hello guys,

I'm trying to throw an exception when the program receives a non integer parameters. ie. a string
I have looked at many examples on the internet and have so far failed to come up with a working solution. My test case continually fails.
I am not overly familiar with the try/catch method but I think that would be the logical way to go about things, any help would be great thanks.

public Triangle(String parameters) throws TriangleException { //just a snippet of my code Scanner scanner = new Scanner(parameters).useDelimiter(","); try { int[] sides = new int[3]; if (sides[0] > 500 || sides[1] > 500 || sides[2] > 500) { throw new TriangleException("Invalid Triangle: One or more parameter is outside the valid range(1-500) of a triangle"); } else { throw new TriangleException("Valid Triangle"); } } catch (NumberFormatException nfe) { throw new TriangleException("Invalid Triangle: Parameter is not an integer"); } }

// my junit test public void test07NonIntegerData() throws Exception { try { //Test to see if a triangle can be created Triangle t = new Triangle("one,two,three"); fail("Exception Expected – Should not Get HERE!"); } catch (TriangleException te) { assertEquals("Invalid Triangle: Parameter is not an integer", te.getMessage()); } }

Thank you Sir I have realized the errors of my ways.

Hi thanks for your advice. I have modified my code and now it is throwing an exception in the correct manner.
However, I am now having difficultly in writing the product code to throw the correct exception.
I wish to throw an exception for "too many parameters" and "too few parameters" as we know a triangle should take 3 parameters.
This is what I have come up with so far. The code I thought would work is in my previous post.
Is it possible you could help me throw those two exceptions?

Thanks

public class Triangle { // Represent the 3 sides of a triangle private static int side1; private static int side2; private static int side3; //private double area; public Triangle(String paramenters) throws TriangleException { Scanner scanner = new Scanner("0,0,0").useDelimiter(","); while (scanner.hasNextInt()) { int num = scanner.nextInt(); if (num == 0) throw new TriangleException("Too many parameters"); } }

Hi guys,

I'm relatively new to java and I am currently struggling to get my head around the scanner and throwing exceptions. I have written the
below code but every time I try running my test I get a failure message. Is it possible one of you guy could tell me where Im going wrong?
Thank you.

my java code public class Triangle { // Represent the 3 sides of a triangle private static int side1; private static int side2; private static int side3; //private double area; public Triangle(String paramenters) throws TriangleException { Scanner scan = new Scanner("0,0,0").useDelimiter(","); int side1 = scan.nextInt(); int side2 = scan.nextInt(); int side3 = scan.nextInt(); scan.close(); } protected static void validate(String paramenters) throws TriangleException { Scanner scan = new Scanner("0,0,0").useDelimiter(","); int[] sides = new int[3]; for(int i = 0; i < 4; i++) if(scan.hasNextInt()){ for( i = 0; i < 4; i++) if(scan.hasNextInt()) { if (i > 2) throw new TriangleException("Too many parameters"); sides[i] = scan.nextInt(); } else{ return;}} }


//my junit test public class TriangleTest extends TestCase { public void testTriangleTooManyParameters() throws Exception { try { Triangle t = new Triangle("10,10,10,10"); fail("Exception Expected – Should not Get HERE!"); } catch (TriangleException te) { assertEquals("Too many parameters", te.getMessage()); } } }