FairShareScheduling.java

packagecom.thealgorithms.scheduling;

importjava.util.HashMap;
importjava.util.Map;

/**
 * FairShareScheduling allocates CPU resources equally among users or groups
 * instead of individual tasks. Each group gets a proportional share,
 * preventing resource hogging by a single user's processes.
 *
 * Use Case: Multi-user systems where users submit multiple tasks simultaneously,
 * such as cloud environments.
 *
 * @author Hardvan
 */
publicfinalclassFairShareScheduling {

staticclassUser {
Stringname;
intallocatedResources;
inttotalWeight;

User(Stringname) {
this.name = name;
this.allocatedResources = 0;
this.totalWeight = 0;
 }

voidaddWeight(intweight) {
this.totalWeight += weight;
 }
 }

privatefinalMap<String, User> users; // username -> User

publicFairShareScheduling() {
users = newHashMap<>();
 }

publicvoidaddUser(StringuserName) {
users.putIfAbsent(userName, newUser(userName));
 }

publicvoidaddTask(StringuserName, intweight) {
Useruser = users.get(userName);
if (user != null) {
user.addWeight(weight);
 }
 }

publicvoidallocateResources(inttotalResources) {
inttotalWeights = users.values().stream().mapToInt(user -> user.totalWeight).sum();
for (Useruser : users.values()) {
user.allocatedResources = (int) ((double) user.totalWeight / totalWeights * totalResources);
 }
 }

publicMap<String, Integer> getAllocatedResources() {
Map<String, Integer> allocation = newHashMap<>();
for (Useruser : users.values()) {
allocation.put(user.name, user.allocatedResources);
 }
returnallocation;
 }
}