создана базовая сущность, репозитории и тд. (папка core)

backend/build.gradle

@@ -19,6 +19,8 @@ dependencies {
 	implementation 'org.springframework.boot:spring-boot-starter-web' 
 	implementation 'org.springframework.boot:spring-boot-starter-actuator'
 	implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.3.0'
+	implementation 'org.modelmapper:modelmapper:3.2.0'
+
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 

backend/src/main/java/com/example/backend/categories/model/CategorieEntity.java

@@ -0,0 +1,7 @@
+package com.example.backend.categories.model;
+
+import com.example.backend.core.model.BaseEntity;
+
+public class CategorieEntity extends BaseEntity {
+
+}

backend/src/main/java/com/example/backend/core/configurations/Constants.java

@@ -0,0 +1,8 @@
+package com.example.backend.core.configurations;
+
+public class Constants {
+    public static final String API_URL = "/api/1.0";
+
+    private Constants() {
+    }
+}

backend/src/main/java/com/example/backend/core/configurations/MapperConfiguration.java

@@ -0,0 +1,13 @@
+package com.example.backend.core.configurations;
+
+import org.modelmapper.ModelMapper;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class MapperConfiguration {
+    @Bean
+    ModelMapper modelMapper() {
+        return new ModelMapper();
+    }
+}

backend/src/main/java/com/example/backend/core/configurations/WebConfig.java

@@ -1,4 +1,4 @@
-package com.example.backend;
+package com.example.backend.core.configurations;
 
 import org.springframework.context.annotation.Configuration;
 import org.springframework.lang.NonNull;

backend/src/main/java/com/example/backend/core/model/BaseEntity.java

@@ -0,0 +1,23 @@
+package com.example.backend.core.model;
+
+public class BaseEntity {
+
+    public Integer Id;
+
+    protected BaseEntity() {
+
+    }
+
+    protected BaseEntity(Integer id) {
+        Id = id;
+    }
+
+    public Integer getId() {
+        return Id;
+    }
+
+    public void setId(Integer id) {
+        Id = id;
+    }
+
+}

backend/src/main/java/com/example/backend/core/repository/CommonRepository.java

@@ -0,0 +1,19 @@
+package com.example.backend.core.repository;
+
+import java.util.List;
+
+public interface CommonRepository<E, T> {
+
+    List<E> getAll();
+
+    E get(T id);
+
+    E create(E entity);
+
+    E update(E entity);
+
+    E delete(E entity);
+
+    void deleteAll();
+
+}

backend/src/main/java/com/example/backend/core/repository/MapRepository.java

@@ -0,0 +1,65 @@
+package com.example.backend.core.repository;
+
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import com.example.backend.core.model.BaseEntity;
+
+public abstract class MapRepository<E extends BaseEntity> implements CommonRepository<E, Integer> {
+
+    private final Map<Integer, E> entities = new TreeMap<>();
+    private Integer lastId = 0;
+
+    private boolean checkNull(E entity) {
+        if (get(entity.getId()) == null)
+            return false;
+        return true;
+    }
+
+    protected MapRepository() {
+
+    }
+
+    @Override
+    public List<E> getAll() {
+        return entities.values().stream().toList();
+    }
+
+    @Override
+    public E get(Integer id) {
+        return entities.get(id);
+    }
+
+    @Override
+    public E create(E entity) {
+        lastId++;
+        entity.setId(lastId);
+        entities.put(lastId, entity);
+        return entity;
+    }
+
+    @Override
+    public E update(E entity) {
+        if (checkNull(entity)) {
+            entities.put(lastId, entity);
+            return entity;
+        }
+        return null;
+    }
+
+    @Override
+    public E delete(E entity) {
+        if (checkNull(entity)) {
+            entities.remove(entity.getId());
+            return entity;
+        }
+        return null;
+    }
+
+    @Override
+    public void deleteAll() {
+        entities.clear();
+        lastId = 0;
+    }
+}