feat: Idempotent Consumer Microservice Pattern #2683 (#3082)

* added idempotent consumer pattern * updated doc * fixed bug in RequestService * add test converage * Add test converage to state machine * renamed module and added code example
2026-05-16 12:59:13 +00:00 · 2024-11-11 16:59:35 +01:00
parent 25bb77eee7
commit 2a2c5605bc
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+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.idempotentconsumer;
+
+import java.util.Optional;
+import java.util.UUID;
+import org.springframework.stereotype.Service;
+
+/**
+ * This service is responsible for handling request operations including
+ * creation, start, and completion of requests.
+ */
+@Service
+public class RequestService {
+  RequestRepository requestRepository;
+  RequestStateMachine requestStateMachine;
+
+  public RequestService(RequestRepository requestRepository,
+                        RequestStateMachine requestStateMachine) {
+    this.requestRepository = requestRepository;
+    this.requestStateMachine = requestStateMachine;
+  }
+
+  /**
+   * Creates a new Request or returns an existing one by it's UUID.
+   * This operation is idempotent: performing it once or several times
+   * successively leads to an equivalent result.
+   *
+   * @param uuid The unique identifier for the Request.
+   * @return Return existing Request or save and return a new Request.
+   */
+  public Request create(UUID uuid) {
+    Optional<Request> optReq = requestRepository.findById(uuid);
+    if (!optReq.isEmpty()) {
+      return optReq.get();
+    }
+    return requestRepository.save(new Request(uuid));
+  }
+
+  /**
+   * Starts the Request assigned with the given UUID.
+   *
+   * @param uuid The unique identifier for the Request.
+   * @return The started Request.
+   * @throws RequestNotFoundException if a Request with the given UUID is not found.
+   */
+  public Request start(UUID uuid) {
+    Optional<Request> optReq = requestRepository.findById(uuid);
+    if (optReq.isEmpty()) {
+      throw new RequestNotFoundException(uuid);
+    }
+    return requestRepository.save(requestStateMachine.next(optReq.get(), Request.Status.STARTED));
+  }
+
+  /**
+   * Complete the Request assigned with the given UUID.
+   *
+   * @param uuid The unique identifier for the Request.
+   * @return The completed Request.
+   * @throws RequestNotFoundException if a Request with the given UUID is not found.
+   */
+  public Request complete(UUID uuid) {
+    Optional<Request> optReq = requestRepository.findById(uuid);
+    if (optReq.isEmpty()) {
+      throw new RequestNotFoundException(uuid);
+    }
+    return requestRepository.save(requestStateMachine.next(optReq.get(), Request.Status.COMPLETED));
+  }
+}