[Association - Step 1단계] OneToMany (FetchType.EAGER)

src/main/java/constants/CommonConstants.java

@@ -9,4 +9,6 @@ private CommonConstants() {
     public static final String COMMA = ", ";
     public static final String EQUAL = " = ";
     public static final String AND = " and ";
+    public static final String PERIOD = ".";
+    public static final String UNDER_SCORE = "_";
 }

src/main/java/docs/lecture.md

@@ -0,0 +1,28 @@
+## 3/16
+
+### 구현
+```markdown
+- Query
+- Entity
+-> 이렇게 2개의 패키지로 나누고, 1주차 미션과 약간 별개일 수 있다.
+
+- SessionImpl 에 의해 session 을 계속 넣어서 다닌다.
+    - `return new StatefulPersistenceContext(this);`
+- StatefulPersistenceContext
+    - `entitiesByKey`
+    - `collectionsByKey`
+- AnnotationBinder 참고
+
+- InFlightMetadataCollector
+    - metadata 수집
+    - 캐싱 설정(default = true)
+
+```
+
+### logging
+```markdown
+- logging.level.org.hibernate.boot=trace
+- logging.level.org.hibernate=trace => 직접 api 실행해서 로깅 확인
+- Spring 은 로깅해서 확인해보는 것을 추천 => Spring 공부!
+```
+

src/main/java/docs/step1.md

@@ -0,0 +1,20 @@
+# 1단계 - OneToMany (FetchType.EAGER)
+
+## 요구사항 1 - Join Query 만들기
+
+- Sql 쿼리 문을 수정해 보자
+```java
+public class CustomSelect {
+
+}
+
+```
+
+## 요구사항 2 - Join Query 를 만들어 Entity 화 해보기
+
+- FetchType.EAGER 인 경우
+```java
+public class SimplePersistenceContext implements PersistenceContext {
+
+}
+```

src/main/java/entity/Order.java

@@ -0,0 +1,69 @@
+package entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
+
+import java.util.List;
+import java.util.Objects;
+
+@Entity
+@Table(name = "orders")
+public class Order {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "order_number")
+    private String orderNumber;
+
+    @OneToMany(fetch = FetchType.EAGER)
+    @JoinColumn(name = "order_id")
+    private List<OrderItem> orderItems;
+
+    public Order() {
+    }
+
+    public Order(Long id, String orderNumber, List<OrderItem> orderItems) {
+        this.id = id;
+        this.orderNumber = orderNumber;
+        this.orderItems = orderItems;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getOrderNumber() {
+        return orderNumber;
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (this == object) return true;
+        if (object == null || getClass() != object.getClass()) return false;
+        Order order = (Order) object;
+        return Objects.equals(id, order.id) && Objects.equals(orderNumber, order.orderNumber) && Objects.equals(orderItems, order.orderItems);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, orderNumber, orderItems);
+    }
+
+    @Override
+    public String toString() {
+        return "Order{" +
+                "id=" + id +
+                ", orderNumber='" + orderNumber + '\'' +
+                ", orderItems=" + orderItems +
+                '}';
+    }
+}

src/main/java/entity/OrderItem.java

@@ -0,0 +1,65 @@
+package entity;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+
+import java.util.Objects;
+
+@Entity
+@Table(name = "order_items")
+public class OrderItem {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String product;
+
+    private Integer quantity;
+
+    public OrderItem() {
+    }
+
+    public OrderItem(Long id, String product, Integer quantity) {
+        this.id = id;
+        this.product = product;
+        this.quantity = quantity;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getProduct() {
+        return product;
+    }
+
+    public Integer getQuantity() {
+        return quantity;
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (this == object) return true;
+        if (object == null || getClass() != object.getClass()) return false;
+        OrderItem orderItem = (OrderItem) object;
+        return Objects.equals(id, orderItem.id) && Objects.equals(product, orderItem.product) && Objects.equals(quantity, orderItem.quantity);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, product, quantity);
+    }
+
+    @Override
+    public String toString() {
+        return "OrderItem{" +
+                "id=" + id +
+                ", product='" + product + '\'' +
+                ", quantity=" + quantity +
+                '}';
+    }
+}

src/main/java/persistence/context/SimplePersistenceContext.java

@@ -1,7 +1,5 @@
 package persistence.context;
 
-import dialect.Dialect;
-import dialect.H2Dialect;
 import persistence.entity.EntityCacheKey;
 import persistence.entity.EntitySnapshot;
 import pojo.FieldInfos;
@@ -13,7 +11,6 @@
 
 public class SimplePersistenceContext implements PersistenceContext {
 
-    private final Dialect dialect = new H2Dialect();
     private final Map<EntityCacheKey, Object> entitiesByKey = new HashMap<>();
     private final Map<EntityCacheKey, EntitySnapshot> entitySnapshotsByKey = new HashMap<>();
 

src/main/java/persistence/entity/CustomJpaRepository.java

@@ -28,8 +28,8 @@ private boolean isNew(T entity) {
         try {
             Field field = new FieldInfos(entity.getClass().getDeclaredFields()).getIdField();
             IdField idField = new IdField(field, entity);
-            return idField.getFieldInfoTemp().getFieldValue() == null
-                    || isBlankOrEmpty(idField.getFieldInfoTemp().getFieldValue().getValue());
+            return idField.getEntityColumn().getFieldValue() == null
+                    || isBlankOrEmpty(idField.getEntityColumn().getFieldValue().getValue());
         } catch (IllegalArgumentException e) {
             return false;
         }

src/main/java/persistence/entity/EntityEntry.java

@@ -19,5 +19,6 @@ public interface EntityEntry {
     void postRemove();
 
     void preReadOnly();
+
     void postReadOnly();
 }

src/main/java/persistence/entity/EntityLoader.java

@@ -7,4 +7,6 @@ public interface EntityLoader {
     <T> T findById(Class<T> clazz, Object entity, Object condition);
 
     <T> List<T> findAll(Class<T> clazz);
+
+    <T> List<T> findByIdWithAssociation(Class<T> clazz, Object entity, Object condition);
 }

src/main/java/persistence/entity/EntityLoaderImpl.java

@@ -2,7 +2,9 @@
 
 import jdbc.JdbcTemplate;
 import jdbc.RowMapperImpl;
+import persistence.sql.dml.CustomSelectQueryBuilder;
 import persistence.sql.dml.SelectQueryBuilder;
+import pojo.EntityJoinMetaData;
 import pojo.EntityMetaData;
 
 import java.util.List;
@@ -27,4 +29,24 @@ public <T> List<T> findAll(Class<T> clazz) {
         SelectQueryBuilder selectQueryBuilder = new SelectQueryBuilder(entityMetaData);
         return jdbcTemplate.query(selectQueryBuilder.findAllQuery(), new RowMapperImpl<>(clazz));
     }
+
+    //연관관계가 있는 경우 & eager 타입만 고려
+    @Override
+    public <T> List<T> findByIdWithAssociation(Class<T> clazz, Object entity, Object condition) {
+        CustomSelectQueryBuilder customSelectQueryBuilder = new CustomSelectQueryBuilder(entityMetaData);
+
+        EntityJoinMetaData entityJoinMetaData = entityMetaData.getEntityJoinMetaData();
+        if (!entityJoinMetaData.isLazy()) {
+            return eagerTypeQuery(customSelectQueryBuilder, clazz, entity);
+        }
+
+        //TODO 추후 lazy 타입 넣을 예정
+        return jdbcTemplate.query(customSelectQueryBuilder.findByIdJoinQuery(entity, clazz), new RowMapperImpl<>(clazz));
+
+    }
+
+    private <T> List<T> eagerTypeQuery(CustomSelectQueryBuilder customSelectQueryBuilder, Class<T> clazz, Object entity) {
+        return jdbcTemplate.query(customSelectQueryBuilder.findByIdJoinQuery(entity, clazz), new RowMapperImpl<>(clazz));
+
+    }
 }

src/main/java/persistence/entity/EntitySnapshot.java

@@ -1,6 +1,6 @@
 package persistence.entity;
 
-import pojo.FieldInfo;
+import pojo.EntityColumn;
 import pojo.FieldInfos;
 
 import java.lang.reflect.Field;
@@ -17,7 +17,7 @@ public class EntitySnapshot {
     public EntitySnapshot(Object entity) {
         List<Field> fields = new FieldInfos(entity.getClass().getDeclaredFields()).getIdAndColumnFields();
         this.map = fields.stream()
-                .map(field -> new FieldInfo(field, entity))
+                .map(field -> new EntityColumn(field, entity))
                 .collect(Collectors.toMap(
                         fieldInfo -> fieldInfo.getFieldName().getName(),
                         fieldInfo -> fieldInfo.getFieldValue().getValue()

src/main/java/persistence/sql/ddl/CreateQueryBuilder.java

@@ -34,9 +34,10 @@ public CreateQueryBuilder(Dialect dialect, EntityMetaData entityMetaData) {
 
     public String createTable(Object entity) {
         FieldInfos fieldInfos = new FieldInfos(entity.getClass().getDeclaredFields());
-        return String.format(CREATE_TABLE_QUERY, entityMetaData.getTableInfo().getName(), createClause(fieldInfos.getFieldDataList(), entity));
+        return String.format(CREATE_TABLE_QUERY, entityMetaData.getEntityName(), createClause(fieldInfos.getFieldDataList(), entity));
     }
 
+    //create 시에 JoinColumn 어노테이션이 있는 필드는 -> JoinColumn 의 name 을 그 필드 객체 생성 시 만들어줘야 한다.
     private String createClause(List<Field> fields, Object entity) {
         return fields.stream()
                 .filter(field -> !field.isAnnotationPresent(Transient.class))

src/main/java/persistence/sql/ddl/DropQueryBuilder.java

@@ -4,7 +4,7 @@
 
 public class DropQueryBuilder {
 
-    private static final String DROP_TABLE_QUERY = "DROP TABLE %s IF EXISTS;";
+    private static final String DROP_TABLE_QUERY = "DROP TABLE IF EXISTS %s;";
 
     private final EntityMetaData entityMetaData;
 
@@ -13,6 +13,6 @@ public DropQueryBuilder(EntityMetaData entityMetaData) {
     }
 
     public String dropTable() {
-        return String.format(DROP_TABLE_QUERY, entityMetaData.getTableInfo().getName());
+        return String.format(DROP_TABLE_QUERY, entityMetaData.getEntityName());
     }
 }

src/main/java/persistence/sql/dml/CustomSelectQueryBuilder.java

@@ -0,0 +1,57 @@
+package persistence.sql.dml;
+
+import pojo.EntityJoinMetaData;
+import pojo.EntityMetaData;
+import pojo.FieldInfos;
+import pojo.FieldName;
+import pojo.IdField;
+
+import java.lang.reflect.Field;
+
+import static constants.CommonConstants.COMMA;
+import static constants.CommonConstants.PERIOD;
+
+public class CustomSelectQueryBuilder {
+
+    private static final String FIND_BY_ID_JOIN_QUERY = "SELECT %s FROM %s LEFT JOIN %s ON %s = %s WHERE %s = %s;";
+
+    private final EntityMetaData entityMetaData;
+    private final EntityJoinMetaData entityJoinMetaData;
+
+    public CustomSelectQueryBuilder(EntityMetaData entityMetaData) {
+        this.entityMetaData = entityMetaData;
+        this.entityJoinMetaData = entityMetaData.getEntityJoinMetaData();
+    }
+
+    public String findByIdJoinQuery(Object entity, Class<?> clazz) {
+        Field field = new FieldInfos(clazz.getDeclaredFields()).getIdField();
+        IdField idField = new IdField(field, entity);
+
+        String metaDataEntityName = entityMetaData.getEntityName();
+        String joinMetaDataEntityName = entityJoinMetaData.getEntityName();
+
+        return String.format(FIND_BY_ID_JOIN_QUERY, getSelectData(), metaDataEntityName, joinMetaDataEntityName,
+                metaDataEntityName + PERIOD + idField.getFieldNameData(),
+                joinMetaDataEntityName + PERIOD + entityJoinMetaData.getJoinColumnName(),
+                metaDataEntityName + PERIOD + idField.getFieldNameData(), idField.getFieldValueData());
+    }
+
+    private String getSelectData() {
+        String entityData = entityMetaData.getEntityColumns()
+                .stream()
+                .map(entityColumn -> entityColumn.getFieldName().getName())
+                .map(name -> entityMetaData.getEntityName() + PERIOD + name)
+                .reduce((o1, o2) -> String.join(COMMA, o1, o2))
+                .orElseThrow(() -> new IllegalStateException("Id 혹은 Column 타입이 없습니다."));
+
+        String ownerEntityData = entityJoinMetaData.getFieldNames()
+                .stream()
+                .map(FieldName::getName)
+                .map(name -> entityJoinMetaData.getEntityName() + PERIOD + name)
+                .reduce((o1, o2) -> String.join(COMMA, o1, o2))
+                .orElseThrow(() -> new IllegalStateException("Id 혹은 Column 타입이 없습니다."));
+
+        return entityData + COMMA + ownerEntityData;
+    }
+
+}

src/main/java/persistence/sql/dml/DeleteQueryBuilder.java

@@ -17,7 +17,7 @@ public DeleteQueryBuilder(EntityMetaData entityMetaData) {
     }
 
     public String deleteQuery(IdField idField) {
-        return String.format(DELETE_QUERY, entityMetaData.getTableInfo().getName(), idField.getFieldNameData(), idField.getFieldValueData());
+        return String.format(DELETE_QUERY, entityMetaData.getEntityName(), idField.getFieldNameData(), idField.getFieldValueData());
     }
 
     public String deleteByIdQuery(Object entity) {

src/main/java/persistence/sql/dml/SelectQueryBuilder.java

@@ -18,13 +18,13 @@ public SelectQueryBuilder(EntityMetaData entityMetaData) {
     }
 
     public String findAllQuery() {
-        return String.format(FIND_ALL_QUERY, entityMetaData.getTableInfo().getName());
+        return String.format(FIND_ALL_QUERY, entityMetaData.getEntityName());
     }
 
     public String findByIdQuery(Object entity, Class<?> clazz, Object condition) {
         Field field = new FieldInfos(clazz.getDeclaredFields()).getIdField();
         IdField idField = new IdField(field, entity);
-        return String.format(FIND_BY_ID_QUERY, entityMetaData.getTableInfo().getName(),
+        return String.format(FIND_BY_ID_QUERY, entityMetaData.getEntityName(),
                 idField.getFieldNameData(), condition);
     }
 }