From 648572a8c53540d64de52a4692d7c13ff81a4cb9 Mon Sep 17 00:00:00 2001 From: doxxx Date: Wed, 11 Sep 2024 21:49:36 +0900 Subject: [PATCH] Refactor ProcessDetails and PreemptivePriorityScheduling (#5448) * Refactor ProcessDetails and PreemptivePriorityScheduling for consistency * fix formatting * fix formatting * Improve test readability and maintainability --- .../devutils/entities/ProcessDetails.java | 12 +++++ .../PreemptivePriorityScheduling.java | 54 +++++++++---------- .../PreemptivePrioritySchedulingTest.java | 35 ++++++------ 3 files changed, 55 insertions(+), 46 deletions(-) diff --git a/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java b/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java index 388fb3fd9..b8b863eda 100644 --- a/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java +++ b/src/main/java/com/thealgorithms/devutils/entities/ProcessDetails.java @@ -6,6 +6,14 @@ public class ProcessDetails { private int burstTime; private int waitingTime; private int turnAroundTime; + private int priority; + + public ProcessDetails(final String processId, final int arrivalTime, final int burstTime, int priority) { + this.processId = processId; + this.arrivalTime = arrivalTime; + this.burstTime = burstTime; + this.priority = priority; + } public ProcessDetails(final String processId, final int arrivalTime, final int burstTime) { this.processId = processId; @@ -33,6 +41,10 @@ public class ProcessDetails { return turnAroundTime; } + public int getPriority() { + return priority; + } + public void setProcessId(final String processId) { this.processId = processId; } diff --git a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java index 9bcd5df81..27d85a94d 100644 --- a/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java +++ b/src/main/java/com/thealgorithms/scheduling/PreemptivePriorityScheduling.java @@ -1,5 +1,6 @@ package com.thealgorithms.scheduling; +import com.thealgorithms.devutils.entities.ProcessDetails; import java.util.ArrayList; import java.util.Comparator; import java.util.List; @@ -7,44 +8,35 @@ import java.util.PriorityQueue; /** * Preemptive Priority Scheduling Algorithm + * * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi) */ +public class PreemptivePriorityScheduling { + protected final List processes; + protected final List ganttChart; -class Process { - String name; - int arrivalTime; - int burstTime; - int priority; - - Process(String name, int arrivalTime, int burstTime, int priority) { - this.name = name; - this.arrivalTime = arrivalTime; - this.burstTime = burstTime; - this.priority = priority; + public PreemptivePriorityScheduling(List processes) { + this.processes = new ArrayList<>(processes); + this.ganttChart = new ArrayList<>(); } -} -public final class PreemptivePriorityScheduling { - private PreemptivePriorityScheduling() { - } - public static List preemptivePriorityScheduling(List processes) { - List ganttChart = new ArrayList<>(); - PriorityQueue readyQueue = new PriorityQueue<>(Comparator.comparingInt(p -> - p.priority)); + public void scheduleProcesses() { + PriorityQueue readyQueue = new PriorityQueue<>(Comparator.comparingInt(ProcessDetails::getPriority).reversed().thenComparingInt(ProcessDetails::getArrivalTime)); int currentTime = 0; + List arrivedProcesses = new ArrayList<>(); while (!processes.isEmpty() || !readyQueue.isEmpty()) { - while (!processes.isEmpty() && processes.get(0).arrivalTime <= currentTime) { - readyQueue.add(processes.remove(0)); - } + updateArrivedProcesses(currentTime, arrivedProcesses); + readyQueue.addAll(arrivedProcesses); + arrivedProcesses.clear(); if (!readyQueue.isEmpty()) { - Process currentProcess = readyQueue.poll(); + ProcessDetails currentProcess = readyQueue.poll(); + ganttChart.add(currentProcess.getProcessId()); + currentProcess.setBurstTime(currentProcess.getBurstTime() - 1); - ganttChart.add(currentProcess.name); - currentProcess.burstTime--; - - if (currentProcess.burstTime > 0) { + if (currentProcess.getBurstTime() > 0) { readyQueue.add(currentProcess); } } else { @@ -53,7 +45,15 @@ public final class PreemptivePriorityScheduling { currentTime++; } + } - return ganttChart; + private void updateArrivedProcesses(int currentTime, List arrivedProcesses) { + processes.removeIf(process -> { + if (process.getArrivalTime() <= currentTime) { + arrivedProcesses.add(process); + return true; + } + return false; + }); } } diff --git a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java index 1c8a25dfd..d0005dda9 100644 --- a/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java +++ b/src/test/java/com/thealgorithms/scheduling/PreemptivePrioritySchedulingTest.java @@ -2,32 +2,29 @@ package com.thealgorithms.scheduling; import static org.junit.jupiter.api.Assertions.assertEquals; -import java.util.ArrayList; -import java.util.Arrays; +import com.thealgorithms.devutils.entities.ProcessDetails; import java.util.List; -import org.junit.jupiter.api.Test; +import java.util.stream.Stream; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.Arguments; +import org.junit.jupiter.params.provider.MethodSource; /** * Test Cases of Preemptive Priority Scheduling Algorithm + * * @author [Bama Charan Chhandogi](https://www.github.com/BamaCharanChhandogi) */ class PreemptivePrioritySchedulingTest { + @ParameterizedTest + @MethodSource("provideProcessesAndExpectedSchedules") + void testPreemptivePriorityScheduling(List processes, List expectedSchedule) { + PreemptivePriorityScheduling scheduler = new PreemptivePriorityScheduling(processes); + scheduler.scheduleProcesses(); + assertEquals(expectedSchedule, scheduler.ganttChart); + } - @Test - void testPreemptivePriorityScheduling() { - // Arrange - List processes = new ArrayList<>(); - processes.add(new Process("P1", 0, 5, 10)); - processes.add(new Process("P2", 1, 4, 20)); - processes.add(new Process("P3", 2, 2, 30)); - processes.add(new Process("P4", 4, 1, 40)); - - List expectedGanttChart = Arrays.asList("P1", "P2", "P3", "P3", "P4", "P2", "P2", "P2", "P1", "P1", "P1", "P1"); - - // Act - List actualGanttChart = PreemptivePriorityScheduling.preemptivePriorityScheduling(processes); - - // Assert - assertEquals(expectedGanttChart, actualGanttChart); + static Stream provideProcessesAndExpectedSchedules() { + return Stream.of(Arguments.of(List.of(new ProcessDetails("P1", 0, 5, 2), new ProcessDetails("P2", 1, 4, 4), new ProcessDetails("P3", 2, 2, 6), new ProcessDetails("P4", 4, 1, 8)), List.of("P1", "P2", "P3", "P3", "P4", "P2", "P2", "P2", "P1", "P1", "P1", "P1")), + Arguments.of(List.of(new ProcessDetails("P1", 2, 5, 3), new ProcessDetails("P2", 5, 3, 5), new ProcessDetails("P3", 7, 1, 9)), List.of("Idle", "Idle", "P1", "P1", "P1", "P2", "P2", "P3", "P2", "P1", "P1"))); } }