feat: add in-memory repository with concurrent storage

src/main/java/dev/deklab/sensorapi/controller/MeasurementController.java

@@ -17,7 +17,6 @@ import org.springframework.web.bind.annotation.ResponseStatus;
 
 @RestController
 public class MeasurementController {
-
     private final MeasurementService measurementService;
 
     MeasurementController(MeasurementService measurementService) {
@@ -38,7 +37,7 @@ public class MeasurementController {
     @PostMapping("/measurements")
     @ResponseStatus(HttpStatus.CREATED)
     public Measurement postMeasurement(@RequestBody Measurement measurement) {
-        return measurement;
+        return measurementService.save(measurement);
     }
 
 }

src/main/java/dev/deklab/sensorapi/repository/MeasurementRepository.java

@@ -0,0 +1,33 @@
+package dev.deklab.sensorapi.repository;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.springframework.stereotype.Repository;
+
+import dev.deklab.model.Measurement;
+
+@Repository
+public class MeasurementRepository {
+    private final ConcurrentHashMap<Long, Measurement> store = new ConcurrentHashMap<>();
+    private final AtomicLong idGenerator = new AtomicLong();
+
+    public List<Measurement> findAll() {
+        return new ArrayList<>(store.values());
+    }
+
+    public Optional<Measurement> findById(Long id) {
+        return Optional.ofNullable(store.get(id));
+    }
+
+    public Measurement save(Measurement measurement){
+        Long newId = idGenerator.incrementAndGet();
+        Measurement saved = new Measurement(newId,measurement.temperature(),measurement.humidity());
+        store.put(newId, saved);
+        return saved;
+    }
+
+}

src/main/java/dev/deklab/sensorapi/service/MeasurementService.java

@@ -6,23 +6,22 @@ import java.util.Optional;
 import org.springframework.stereotype.Service;
 
 import dev.deklab.model.Measurement;
+import dev.deklab.sensorapi.repository.MeasurementRepository;
 
 @Service
 public class MeasurementService {
-    private Measurement m1 = new Measurement(1L, 21.5, 48);
-    private Measurement m2 = new Measurement(2L, 25.5, 38);
-    private Measurement m3 = new Measurement(3L, 29.5, 58);
-
-    private List<Measurement> measurements = List.of(m1, m2, m3);
+    private final MeasurementRepository measurementRepository;
+    MeasurementService(MeasurementRepository measurementRepository){
+        this.measurementRepository = measurementRepository;
+    }
     public List<Measurement> returnAllMeasurements() {
-            return measurements;
+        return measurementRepository.findAll();
     }
+
     public Optional<Measurement> searchById(Long id) {
-        for (int i = 0; i < measurements.size(); i++) {
-            if (id.equals(measurements.get(i).id())) {
-                return Optional.of(measurements.get(i));
-            }
-        }
-        return Optional.empty();
+        return measurementRepository.findById(id);
+    }
+    public Measurement save(Measurement measurement){
+        return measurementRepository.save(measurement);
     }
 }