feat: redis 없이 순수 자바만을 사용한 동시성 처리

- volatile의 쓰기 이슈로 인해 AtomicInteger 사용

src/main/java/com/softeer/podoarrival/event/service/ArrivalEventReleaseServiceRedisImpl.java

@@ -0,0 +1,91 @@
+package com.softeer.podoarrival.event.service;
+
+import com.softeer.podoarrival.event.exception.ExistingUserException;
+import com.softeer.podoarrival.event.model.dto.ArrivalApplicationResponseDto;
+import com.softeer.podoarrival.event.model.entity.ArrivalUser;
+import com.softeer.podoarrival.event.model.entity.Role;
+import com.softeer.podoarrival.event.repository.ArrivalUserRepository;
+import com.softeer.podoarrival.security.AuthInfo;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.redisson.api.BatchResult;
+import org.redisson.api.RBatch;
+import org.redisson.api.RedissonClient;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Service;
+
+import java.time.LocalDate;
+import java.util.concurrent.CompletableFuture;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class ArrivalEventReleaseServiceRedisImpl implements ArrivalEventReleaseService {
+
+    private static final Logger specialLogger = LoggerFactory.getLogger("arrivalEventLogger");
+
+    private final RedissonClient redissonClient;
+    private final ArrivalUserRepository arrivalUserRepository;
+
+    private final String ARRIVAL_SET = "arrivalset";
+    private boolean CHECK = false;
+    private static int MAX_ARRIVAL = 100; // default
+
+    /**
+     * 비동기로 Redis 호출하는 메서드
+     * Redisson set을 통해서 전화번호 중복 처리
+     * Redisson lock 대신 set을 사용하여 인원수 처리
+     */
+    @Async("arrivalExecutor")
+    @Override
+    public CompletableFuture<ArrivalApplicationResponseDto> applyEvent(AuthInfo authInfo) {
+        return CompletableFuture.supplyAsync(() -> {
+            String redisKey = LocalDate.now() + ARRIVAL_SET;
+
+            if(CHECK){
+                return new ArrivalApplicationResponseDto(false, authInfo.getName(), authInfo.getPhoneNum(), -1);
+            }
+
+            RBatch batch = redissonClient.createBatch();
+            batch.getSet(redisKey).addAsync(authInfo.getPhoneNum());
+            batch.getSet(redisKey).sizeAsync();
+            BatchResult<?> res = batch.execute();
+
+            //첫번째 응답
+            if(!(boolean) res.getResponses().get(0)){
+                throw new ExistingUserException("이미 응모한 전화번호입니다.");
+            }
+
+            // 로깅 추가
+            specialLogger.info("[응모] 유저 전화번호: {}", authInfo.getPhoneNum());
+
+            int grade = (int) res.getResponses().get(1);
+            // 선착순 순위에 들었다면
+            if(grade <= MAX_ARRIVAL){
+                arrivalUserRepository.save(
+                        ArrivalUser.builder()
+                                .name(authInfo.getName())
+                                .phoneNum(authInfo.getPhoneNum())
+                                .role(Role.ROLE_USER)
+                                .arrivalRank(grade)
+                                .build()
+                );
+                log.info("[당첨] 유저 전화번호 = {}, 등수 = {}", authInfo.getPhoneNum(), grade);
+                return new ArrivalApplicationResponseDto(true, authInfo.getName(), authInfo.getPhoneNum(), grade);
+            } else {
+                CHECK = true;
+                return new ArrivalApplicationResponseDto(false, authInfo.getName(), authInfo.getPhoneNum(), grade);
+            }
+        });
+    }
+
+    public static void setMaxArrival(int val) {
+        MAX_ARRIVAL = val;
+    }
+
+    public static int getMaxArrival() {
+        return MAX_ARRIVAL;
+    }
+}