Add lottery: Ball, Color enum, ColorSupplier, Lottery and main test by chupa-ilona · Pull Request #1997 · mate-academy/jv-lottery

chupa-ilona · 2026-01-27T18:13:45Z

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mateacademy-ai-mentor

Review Summary

Great job implementing the core logic! The program works correctly. However, some changes are needed to meet the project's coding standards before this can be approved. Please address the following checklist violations:

In ColorSupplier.java and Lottery.java, you are creating new Random and ColorSupplier objects on every method call. It's more efficient to create these as private fields and reuse the same instance. [CHECKLIST ITEM #4]
The numbers 3 in Application.java and 100 in Lottery.java are 'magic numbers'. Please declare them as named constants (e.g., private static final int MAX_BALL_NUMBER = 100;). [CHECKLIST ITEM #9]
Avoid creating temporary variables when you can return a value directly from a method, for example in Lottery.java and ColorSupplier.java. [CHECKLIST ITEM #2]
Use the .name() method instead of .toString() for getting the string value of an enum. [CHECKLIST ITEM #10]

Addressing these points will significantly improve your code's quality and adherence to best practices.

✨ Please rate this review in the Platform's notification center¹. I will be grateful for your feedback! ✨

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src/main/java/core/basesyntax/Application.java

mateacademy-ai-mentor · 2026-01-27T18:15:47Z

src/main/java/core/basesyntax/ColorSupplier.java

 public class ColorSupplier {
    public String getRandomColor() {
-        return null;
+        Colors rand_color = Colors.values()[new Random().nextInt(Colors.values().length)];


This violates checklist item #4: 'Don't create several instances of the same class if you can use only one instance for your purposes'. A new Random() object is created with every method call. It is more efficient to create a single Random instance as a private field of the ColorSupplier class.

mateacademy-ai-mentor · 2026-01-27T18:15:48Z

src/main/java/core/basesyntax/ColorSupplier.java

 public class ColorSupplier {
    public String getRandomColor() {
-        return null;
+        Colors rand_color = Colors.values()[new Random().nextInt(Colors.values().length)];


This line introduces a temporary variable rand_color, which violates checklist item #2: 'Don't create temporary variables if you can directly return value from the method'. The value could be returned directly.

mateacademy-ai-mentor · 2026-01-27T18:15:48Z

src/main/java/core/basesyntax/ColorSupplier.java

    public String getRandomColor() {
-        return null;
+        Colors rand_color = Colors.values()[new Random().nextInt(Colors.values().length)];
+        return rand_color.toString();


This violates checklist item #10: 'Use name() for getting String representation of enum constants'. The name() method should be used instead of toString() to get the string representation of an enum constant.

mateacademy-ai-mentor · 2026-01-27T18:15:48Z

src/main/java/core/basesyntax/Lottery.java

+
+public class Lottery {
+    public Ball getRandomBall(){
+        Ball ball = new Ball(new ColorSupplier().getRandomColor(),


This violates checklist item #4: 'Don't create several instances of the same class if you can use only one instance for your purposes'. A new ColorSupplier object is created on every call to getRandomBall(). It's more efficient to make ColorSupplier a private field of the Lottery class and initialize it once.

mateacademy-ai-mentor · 2026-01-27T18:15:48Z

src/main/java/core/basesyntax/Lottery.java

+public class Lottery {
+    public Ball getRandomBall(){
+        Ball ball = new Ball(new ColorSupplier().getRandomColor(),
+                new Random().nextInt(100) + 1);


This violates checklist item #9: 'All magic numbers in your code should be constants.' The number 100 should be declared as a named constant to improve readability and maintainability, for example private static final int MAX_BALL_NUMBER = 100;.

mateacademy-ai-mentor · 2026-01-27T18:15:48Z

src/main/java/core/basesyntax/Lottery.java

+public class Lottery {
+    public Ball getRandomBall(){
+        Ball ball = new Ball(new ColorSupplier().getRandomColor(),
+                new Random().nextInt(100) + 1);


This violates checklist item #4: 'Don't create several instances of the same class if you can use only one instance for your purposes'. Creating a new Random object each time the method is called is inefficient. It's better practice to create a single Random instance as a private field within the Lottery class.

mateacademy-ai-mentor · 2026-01-27T18:15:48Z

src/main/java/core/basesyntax/Lottery.java

+        Ball ball = new Ball(new ColorSupplier().getRandomColor(),
+                new Random().nextInt(100) + 1);
+        return ball;


This violates checklist item #2: 'Don't create temporary variables if you can directly return value from the method'. You can create and return the Ball object in a single line, like return new Ball(...).

made BALLS_COUNT non final

mateacademy-ai-mentor

Review Summary

Excellent progress on this task! You've successfully addressed almost all the feedback from the previous review, and your code is very close to being perfect.

However, one important issue from the last review remains. In src/main/java/core/basesyntax/Application.java, the number 3 is still used as a 'magic number'. This violates a core requirement to declare all such numbers as constants for better readability and maintainability [CHECKLIST ITEM #9].

Please declare it as a named constant, for example:
private static final int BALLS_COUNT = 3;

Once you make this small correction, your solution will be ready for approval. Keep up the great work!

✨ Please rate this review in the Platform's notification center¹. I will be grateful for your feedback! ✨

Important

Fix the issues, commit the changes, and then re-request my review using the Re-request review button² in the Reviewers tab.

Tip

If you have any comments about this review, please leave a message in the Add a comment section below and mention me with the @mateacademy-ai-mentor tag³.
I will read your message during my next review of your pull request. Please do not reply directly to my comments, as that feature is not supported yet.

Caution

Do not close the pull request until the review is complete. Closing it early can lead to unexpected behavior and disrupt the review process.

src/main/java/core/basesyntax/Application.java

mateacademy-ai-mentor

Review Summary

Excellent work! You've successfully addressed the feedback from the previous review, and the code is now in great shape. Your solution correctly implements all functional requirements and adheres to the specified coding standards, especially with the great use of constants for all magic numbers. I am gladly approving your solution, keep up the fantastic work!

✨ Please rate this review in the Platform's notification center¹. I will be grateful for your feedback! ✨

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Add lottery: Ball, Color enum, ColorSupplier, Lottery and main test

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mateacademy-ai-mentor suggested changes Jan 27, 2026

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chupa-ilona added 17 commits January 27, 2026 20:17

Fixed errors

a7d4dc6

Update Application.java

be674cf

Update ColorSupplier.java

0990cf6

Update Lottery.java

0617151

Update Lottery.java

6a3007e

Update Application.java

ca92c55

made BALLS_COUNT non final

Update Lottery.java

a160930

Update ColorSupplier.java

fb59c09

Update Ball.java

03cf689

Update ColorSupplier.java

8ee9a82

Update Application.java

8aef3ec

Update Ball.java

e9153b4

Update Lottery.java

b6097db

Update ColorSupplier.java

07f551e

Update Application.java

8c07573

Update Lottery.java

384ae5b

Update Lottery.java

1c0f07c

chupa-ilona requested a review from mateacademy-ai-mentor January 29, 2026 13:38

mateacademy-ai-mentor suggested changes Jan 29, 2026

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src/main/java/core/basesyntax/Application.java Outdated Show resolved Hide resolved

chupa-ilona added 2 commits January 29, 2026 15:45

Update Application.java

7fdc94d

Update Application.java

2e18217

chupa-ilona requested a review from mateacademy-ai-mentor January 29, 2026 13:47

mateacademy-ai-mentor approved these changes Jan 29, 2026

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Add lottery: Ball, Color enum, ColorSupplier, Lottery and main test#1997

Add lottery: Ball, Color enum, ColorSupplier, Lottery and main test#1997
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