Day 14: Throwing exceptions out the window!

Author: yanncourtel

README.md

@@ -59,6 +59,7 @@ Here are the different challenges :
 - [Day 11: Gather a dependency freshness metric.](exercise/day11/docs/challenge.md)
 - [Day 12: Make your code open for extension.](exercise/day12/docs/challenge.md)
 - [Day 13: Find a way to eliminate the irrelevant, and amplify the essentials of those tests.](exercise/day13/docs/challenge.md)
+- [Day 14: Do not use exceptions anymore.](exercise/day14/docs/challenge.md)
 
 ### Solutions
 A solution proposal will be published here every day during the `Advent Of Craft` containing `the code` and a `step by step` guide.

exercise/day14/docs/challenge.md

@@ -0,0 +1,27 @@
+## Day 14: Throwing exceptions out the window!
+
+Another day in your crafting journey.
+Today the weather is fair and nice.
+
+This is a perfect day for inspiration.
+Today you are taking another step to higher levels.
+
+The exercise of today seems simple, yet it is not.
+You will look at this code base from the previous days.
+
+You can read it.
+
+You can understand it.
+
+_But can you still improve on it?_
+
+While refactoring this code, always remember this:
+**You shall not break the tests.**
+
+> **Challenge of day 14: Do not use exceptions anymore.**
+
+May your crafting journey continue!
+
+- <u>💡HINT:</u> Think of how you can return information about a faulty state.
+
+![snippet of the day](snippet.png)

exercise/day14/docs/snippet.png

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>com.advent-of-craft</groupId>
+        <artifactId>advent-of-craft2023</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>fizzbuzz-part4</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+
+</project>

exercise/day14/pom.xml

@@ -0,0 +1,46 @@
+package games;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.Predicate;
+
+public class FizzBuzz {
+    public static final int MIN = 0;
+    public static final int MAX = 100;
+    public static final int FIZZ = 3;
+    public static final int BUZZ = 5;
+    public static final int FIZZBUZZ = 15;
+
+    private static final Map<Predicate<Integer>, String> mapping;
+
+    static {
+        mapping = new LinkedHashMap<>();
+        mapping.put(i -> is(FIZZBUZZ, i), "FizzBuzz");
+        mapping.put(i -> is(FIZZ, i), "Fizz");
+        mapping.put(i -> is(BUZZ, i), "Buzz");
+    }
+
+    private static boolean is(Integer divisor, Integer input) {
+        return input % divisor == 0;
+    }
+
+    private static boolean isOutOfRange(Integer input) {
+        return input <= MIN || input > MAX;
+    }
+
+    public static String convert(Integer input) throws OutOfRangeException {
+        if (isOutOfRange(input)) {
+            throw new OutOfRangeException();
+        }
+        return convertSafely(input);
+    }
+
+    private static String convertSafely(Integer input) {
+        return mapping.entrySet()
+                .stream()
+                .filter(f -> f.getKey().test(input))
+                .findFirst()
+                .map(Map.Entry::getValue)
+                .orElseGet(input::toString);
+    }
+}

exercise/day14/src/main/java/games/FizzBuzz.java

@@ -0,0 +1,4 @@
+package games;
+
+public class OutOfRangeException extends Exception {
+}

exercise/day14/src/main/java/games/OutOfRangeException.java

@@ -0,0 +1,52 @@
+package games;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class FizzBuzzTests {
+
+    public static Stream<Arguments> validInputs() {
+        return Stream.of(
+                Arguments.of(1, "1"),
+                Arguments.of(67, "67"),
+                Arguments.of(82, "82"),
+                Arguments.of(3, "Fizz"),
+                Arguments.of(66, "Fizz"),
+                Arguments.of(99, "Fizz"),
+                Arguments.of(5, "Buzz"),
+                Arguments.of(50, "Buzz"),
+                Arguments.of(85, "Buzz"),
+                Arguments.of(15, "FizzBuzz"),
+                Arguments.of(30, "FizzBuzz"),
+                Arguments.of(45, "FizzBuzz")
+        );
+    }
+
+    public static Stream<Arguments> invalidInputs() {
+        return Stream.of(
+                Arguments.of(0),
+                Arguments.of(-1),
+                Arguments.of(101)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("validInputs")
+    void returns_number_representation(int input, String expectedResult) throws OutOfRangeException {
+        assertThat(FizzBuzz.convert(input))
+                .isEqualTo(expectedResult);
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidInputs")
+    void throws_an_exception_for_numbers_out_of_range(int input) {
+        assertThatThrownBy(() -> FizzBuzz.convert(input))
+                .isInstanceOf(OutOfRangeException.class);
+    }
+}

exercise/day14/src/test/java/games/FizzBuzzTests.java

@@ -22,6 +22,7 @@
 		<module>day11</module>
 		<module>day12</module>
 		<module>day13</module>
+		<module>day14</module>
     </modules>
 
     <properties>