add CompletableFuture 사용 예시

Author: Integerous

Java/CompleatableFuture.md

@@ -0,0 +1,57 @@
+## CompletableFuture 사용 예시
+>급하게 사용하게 된 CompletableFuture 사용 기록
+
+~~~java
+/**
+     * 벤더 상세조회 (Async)
+     *
+     * @param utmCode 벤더 식별 아이디
+     * @return 벤더 상세조회 응답 객체
+     */
+    public DetailedVendorDTO getDetailedVendorAsync(String utmCode) {
+        CompletableFuture<List<String>> vendorHasServiceAsync = getVendorHasServiceAsync(utmCode);
+        CompletableFuture<List<TokenResponseDTO>> tokensByUtmCodeAsync = getTokensByUtmCodeAsync(utmCode);
+
+        DetailedVendorDTO detailedVendorDTO = vendorHasServiceAsync
+                .thenCombine(tokensByUtmCodeAsync,
+                        (services, tokens) -> DetailedVendorDTO.builder()
+                                .servicesByVendor(services)
+                                .tokenList(tokens)
+                                .build()
+                )
+                .join();
+
+        return detailedVendorDTO;
+    }
+
+    private CompletableFuture<List<String>> getVendorHasServiceAsync(String utmCode) {
+        CompletableFuture future = new CompletableFuture<>();
+        new Thread(() -> {
+            log.info("새로운 쓰레드로 벤더가 사용중인 서비스 목록 조회");
+            List<VendorHasService> vendorHasServiceByUtmCode = vendorHasServiceReadRepository.findVendorHasServiceByUtmCode(utmCode);
+            List<String> services = vendorHasServiceByUtmCode.stream()
+                    .map(DynamoTable::getSk)
+                    .collect(Collectors.toList());
+            future.complete(services);
+        }).start();
+
+        return future;
+    }
+
+    private CompletableFuture<List<TokenResponseDTO>> getTokensByUtmCodeAsync(String utmCode) {
+        CompletableFuture future = new CompletableFuture<>();
+        new Thread(() -> {
+            log.info("새로운 쓰레드로 벤더가 사용중인 토큰 목록 조회");
+            List<Token> tokensByUtmCode = tokenReadRepository.findTokensByUtmCode(utmCode);
+            List<TokenResponseDTO> tokens = tokensByUtmCode.stream()
+                    .map(TokenResponseDTO::from)
+                    .collect(Collectors.toList());
+            future.complete(tokens);
+        }).start();
+
+        return future;
+    }
+~~~
+
+### Reference
+- https://brunch.co.kr/@springboot/267