first solution for result set mappings

gavinking · Dec 20, 2024 · 7ae782e · 7ae782e
1 parent 32821db
commit 7ae782e
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Showing 5 changed files with 77 additions and 1 deletion.
diff --git a/api/src/main/java/jakarta/persistence/ColumnResult.java b/api/src/main/java/jakarta/persistence/ColumnResult.java
@@ -16,6 +16,7 @@
 
 package jakarta.persistence;
 
+import java.lang.annotation.Annotation;
 import java.lang.annotation.Target;
 import java.lang.annotation.Retention;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
@@ -80,4 +81,15 @@
      * @since 2.1
      */
     Class<?> type() default void.class;
+
+    record Map(String name, Class<?> type)
+            implements ColumnResult, SqlResultSetMapping.MappingElement {
+        Map(String name) {
+            this(name, void.class);
+        }
+        @Override
+        public Class<? extends Annotation> annotationType() {
+            return ColumnResult.class;
+        }
+    }
 }
diff --git a/api/src/main/java/jakarta/persistence/ConstructorResult.java b/api/src/main/java/jakarta/persistence/ConstructorResult.java
@@ -16,6 +16,7 @@
 
 package jakarta.persistence;
 
+import java.lang.annotation.Annotation;
 import java.lang.annotation.Target;
 import java.lang.annotation.Retention;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
@@ -87,4 +88,12 @@
      * {@linkplain #targetClass target class}, in order.
      */
     ColumnResult[] columns();
+
+    record Map(Class<?> targetClass, ColumnResult... columns)
+            implements ConstructorResult, SqlResultSetMapping.MappingElement {
+        @Override
+        public Class<? extends Annotation> annotationType() {
+            return ConstructorResult.class;
+        }
+    }
 }
diff --git a/api/src/main/java/jakarta/persistence/EntityResult.java b/api/src/main/java/jakarta/persistence/EntityResult.java
@@ -17,6 +17,7 @@
 
 package jakarta.persistence;
 
+import java.lang.annotation.Annotation;
 import java.lang.annotation.Target;
 import java.lang.annotation.Retention;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
@@ -65,7 +66,7 @@
  */
 @Target({}) 
 @Retention(RUNTIME)
-public @interface EntityResult { 
+public @interface EntityResult {
 
     /**
      * The class of the result.
@@ -90,4 +91,18 @@
      * the entity instance.
      */
     String discriminatorColumn() default "";
+
+    record Map(Class<?> entityClass, String discriminatorColumn, FieldResult[] fields, LockModeType lockMode)
+            implements EntityResult, SqlResultSetMapping.MappingElement {
+        Map(Class<?> entityClass, FieldResult... fields) {
+            this(entityClass, "", fields, LockModeType.NONE);
+        }
+        Map(Class<?> entityClass, String discriminatorColumn, FieldResult... fields) {
+            this(entityClass, discriminatorColumn, fields, LockModeType.NONE);
+        }
+        @Override
+        public Class<? extends Annotation> annotationType() {
+            return EntityResult.class;
+        }
+    }
 }
diff --git a/api/src/main/java/jakarta/persistence/FieldResult.java b/api/src/main/java/jakarta/persistence/FieldResult.java
@@ -17,6 +17,7 @@
 
 package jakarta.persistence;
 
+import java.lang.annotation.Annotation;
 import java.lang.annotation.Target;
 import java.lang.annotation.Retention;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
@@ -72,4 +73,12 @@
      * the column alias, if applicable.
      */
     String column();
+
+    record Map(String name, String column)
+            implements FieldResult {
+        @Override
+        public Class<? extends Annotation> annotationType() {
+            return FieldResult.class;
+        }
+    }
 }
diff --git a/api/src/main/java/jakarta/persistence/SqlResultSetMapping.java b/api/src/main/java/jakarta/persistence/SqlResultSetMapping.java
@@ -17,9 +17,13 @@
 
 package jakarta.persistence;
 
+import java.lang.annotation.Annotation;
 import java.lang.annotation.Repeatable;
 import java.lang.annotation.Target;
 import java.lang.annotation.Retention;
+import java.lang.reflect.Array;
+import java.util.Arrays;
+
 import static java.lang.annotation.ElementType.TYPE;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
@@ -90,4 +94,31 @@
      * Specifies the result set mapping to scalar values.
      */
     ColumnResult[] columns() default {};
+
+    interface MappingElement {}
+
+    record Map(String name, EntityResult[] entities, ConstructorResult[] classes, ColumnResult[] columns)
+            implements SqlResultSetMapping {
+        @SuppressWarnings("unchecked")
+        private static <R> R[] newArrayInstance(Class<R> type, int length) {
+            return (R[]) Array.newInstance(type, length);
+        }
+        static <R> R[] extract(Class<R> type, MappingElement[] mappingElements) {
+            return Arrays.stream(mappingElements)
+                    .filter(type::isInstance)
+                    .toArray(length -> newArrayInstance(type, length));
+        }
+        Map(String name, MappingElement... mappings) {
+            this(name,
+                    extract(EntityResult.class, mappings),
+                    extract(ConstructorResult.class, mappings),
+                    extract(ColumnResult.class, mappings));
+        }
+        @Override
+        public Class<? extends Annotation> annotationType() {
+            return SqlResultSetMapping.class;
+        }
+    }
 }
+
+