diff --git a/DIRECTORY.md b/DIRECTORY.md index e34b9eba1247..1fc9ec0ce9cf 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -560,6 +560,7 @@ * [NonPreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/NonPreemptivePriorityScheduling.java) * [PreemptivePriorityScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java) * [ProportionalFairScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/ProportionalFairScheduling.java) + * [RandomScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java) * [RRScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/RRScheduling.java) * [SelfAdjustingScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SelfAdjustingScheduling.java) * [SJFScheduling](https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/scheduling/SJFScheduling.java) @@ -1192,6 +1193,7 @@ * [NonPreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/NonPreemptivePrioritySchedulingTest.java) * [PreemptivePrioritySchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java) * [ProportionalFairSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/ProportionalFairSchedulingTest.java) + * [RandomSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java) * [RRSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/RRSchedulingTest.java) * [SelfAdjustingSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SelfAdjustingSchedulingTest.java) * [SJFSchedulingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/scheduling/SJFSchedulingTest.java) diff --git a/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java b/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java new file mode 100644 index 000000000000..b7e863b5cfd8 --- /dev/null +++ b/src/main/java/com/thealgorithms/scheduling/RandomScheduling.java @@ -0,0 +1,45 @@ +package com.thealgorithms.scheduling; + +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.List; +import java.util.Random; + +/** + * RandomScheduling is an algorithm that assigns tasks in a random order. + * It doesn't consider priority, deadlines, or burst times, making it + * inefficient but useful in scenarios where fairness or unpredictability + * is required (e.g., load balancing in distributed systems). + * + * Use Case: Distributed systems where randomness helps avoid task starvation. + * + * @author Hardvan + */ +public final class RandomScheduling { + + private final List tasks; + private final Random random; + + /** + * Constructs a new RandomScheduling instance. + * + * @param tasks A collection of task names to be scheduled. + * @param random A Random instance for generating random numbers. + */ + public RandomScheduling(Collection tasks, Random random) { + this.tasks = new ArrayList<>(tasks); + this.random = random; + } + + /** + * Schedules the tasks randomly and returns the randomized order. + * + * @return A list representing the tasks in their randomized execution order. + */ + public List schedule() { + List shuffledTasks = new ArrayList<>(tasks); + Collections.shuffle(shuffledTasks, random); + return shuffledTasks; + } +} diff --git a/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java new file mode 100644 index 000000000000..e2c8777d892f --- /dev/null +++ b/src/test/java/com/thealgorithms/scheduling/RandomSchedulingTest.java @@ -0,0 +1,93 @@ +package com.thealgorithms.scheduling; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.mockito.Mockito.anyInt; +import static org.mockito.Mockito.mock; +import static org.mockito.Mockito.when; + +import java.util.List; +import java.util.Random; +import org.junit.jupiter.api.BeforeEach; +import org.junit.jupiter.api.Test; + +public class RandomSchedulingTest { + + private RandomScheduling randomScheduling; + private Random mockRandom; + + @BeforeEach + public void setup() { + mockRandom = mock(Random.class); // Mocking Random for predictable behavior + } + + @Test + public void testRandomOrder1() { + // Arrange + List tasks = List.of("Task1", "Task2", "Task3"); + // Mock the random sequence to control shuffling: swap 0 <-> 1, and 1 <-> 2. + when(mockRandom.nextInt(anyInt())).thenReturn(1, 2, 0); + randomScheduling = new RandomScheduling(tasks, mockRandom); + + // Act + List result = randomScheduling.schedule(); + + // Assert + assertEquals(List.of("Task1", "Task2", "Task3"), result); + } + + @Test + public void testRandomOrder2() { + // Arrange + List tasks = List.of("A", "B", "C", "D"); + // Mocking predictable swaps for the sequence: [C, B, D, A] + when(mockRandom.nextInt(anyInt())).thenReturn(2, 1, 3, 0); + randomScheduling = new RandomScheduling(tasks, mockRandom); + + // Act + List result = randomScheduling.schedule(); + + // Assert + assertEquals(List.of("A", "C", "B", "D"), result); + } + + @Test + public void testSingleTask() { + // Arrange + List tasks = List.of("SingleTask"); + when(mockRandom.nextInt(anyInt())).thenReturn(0); // No real shuffle + randomScheduling = new RandomScheduling(tasks, mockRandom); + + // Act + List result = randomScheduling.schedule(); + + // Assert + assertEquals(List.of("SingleTask"), result); + } + + @Test + public void testEmptyTaskList() { + // Arrange + List tasks = List.of(); + randomScheduling = new RandomScheduling(tasks, mockRandom); + + // Act + List result = randomScheduling.schedule(); + + // Assert + assertEquals(List.of(), result); // Should return an empty list + } + + @Test + public void testSameTasksMultipleTimes() { + // Arrange + List tasks = List.of("X", "X", "Y", "Z"); + when(mockRandom.nextInt(anyInt())).thenReturn(3, 0, 1, 2); + randomScheduling = new RandomScheduling(tasks, mockRandom); + + // Act + List result = randomScheduling.schedule(); + + // Assert + assertEquals(List.of("Y", "X", "X", "Z"), result); + } +} pFad - Phonifier reborn

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