FEATURE: Add support for Generic mapped superclass (#3692)

* creates support for generics in mapped superclasses

* Changes DeployCreateProperties to allow processing of inheritance hierarchies with generics

* adds tests for ebean-querybean

* bumps querybean-generator version

* fixes tests by changing table names for ProductWithGenericLong and ProductWithGenericString

* Restore format, this reduces the diff

* Restore format, this reduces the diff

---------

Co-authored-by: Rob Bygrave <robin.bygrave@gmail.com>

Author: dsa-ferreira

ebean-core/src/main/java/io/ebeaninternal/server/deploy/parse/DeployCreateProperties.java

@@ -11,6 +11,8 @@
 
 import jakarta.persistence.*;
 import java.lang.reflect.*;
+import java.util.HashMap;
+import java.util.Map;
 
 import static java.lang.System.Logger.Level.*;
 
@@ -35,7 +37,7 @@ public DeployCreateProperties(TypeManager typeManager) {
    * Create the appropriate properties for a bean.
    */
   public void createProperties(DeployBeanDescriptor<?> desc) {
-    createProperties(desc, desc.getBeanType(), 0);
+    createProperties(desc, desc.getBeanType(), 0, new HashMap<>());
     desc.sortProperties();
   }
 
@@ -64,7 +66,7 @@ private boolean ignoreField(Field field) {
    * properties the bean properties from Class. Some of these properties may not map to database
    * columns.
    */
-  private void createProperties(DeployBeanDescriptor<?> desc, Class<?> beanType, int level) {
+  private void createProperties(DeployBeanDescriptor<?> desc, Class<?> beanType, int level, Map<TypeVariable<?>, Class<?>> genericTypeMap) {
     if (beanType.equals(Model.class)) {
       // ignore all fields on model (_$dbName)
       return;
@@ -74,7 +76,7 @@ private void createProperties(DeployBeanDescriptor<?> desc, Class<?> beanType, i
       for (int i = 0; i < fields.length; i++) {
         Field field = fields[i];
         if (!ignoreField(field)) {
-          DeployBeanProperty prop = createProp(desc, field, beanType);
+          DeployBeanProperty prop = createProp(desc, field, beanType, genericTypeMap);
           if (prop != null) {
             // set a order that gives priority to inherited properties
             // push Id/EmbeddedId up and CreatedTimestamp/UpdatedTimestamp down
@@ -95,7 +97,7 @@ private void createProperties(DeployBeanDescriptor<?> desc, Class<?> beanType, i
       if (!superClass.equals(Object.class)) {
         // recursively add any properties in the inheritance hierarchy
         // up to the Object.class level...
-        createProperties(desc, superClass, level + 1);
+        createProperties(desc, superClass, level + 1, mapGenerics(beanType));
       }
     } catch (PersistenceException ex) {
       throw ex;
@@ -116,8 +118,10 @@ private DeployBeanProperty createManyType(DeployBeanDescriptor<?> desc, Class<?>
     return new DeployBeanPropertyAssocMany<>(desc, targetType, manyType);
   }
 
-  private DeployBeanProperty createProp(DeployBeanDescriptor<?> desc, Field field) {
-    Class<?> propertyType = field.getType();
+  private DeployBeanProperty createProp(DeployBeanDescriptor<?> desc, Field field, Map<TypeVariable<?>, Class<?>> genericTypeMap) {
+    Class<?> propertyType = field.getGenericType() instanceof TypeVariable<?>
+      ? genericTypeMap.get(field.getGenericType())
+      : field.getType();
     if (isSpecialScalarType(field)) {
       return new DeployBeanProperty(desc, propertyType, field.getGenericType());
     }
@@ -172,8 +176,8 @@ private boolean isTransientField(Field field) {
     return AnnotationUtil.has(field, Transient.class);
   }
 
-  private DeployBeanProperty createProp(DeployBeanDescriptor<?> desc, Field field, Class<?> beanType) {
-    DeployBeanProperty prop = createProp(desc, field);
+  private DeployBeanProperty createProp(DeployBeanDescriptor<?> desc, Field field, Class<?> beanType, Map<TypeVariable<?>, Class<?>> genericTypeMap) {
+    DeployBeanProperty prop = createProp(desc, field, genericTypeMap);
     if (prop == null) {
       // transient annotation on unsupported type
       return null;
@@ -224,4 +228,40 @@ private Class<?> determineTargetType(Field field) {
     // if targetType is null, then must be set in annotations
     return null;
   }
+
+  private Map<TypeVariable<?>, Class<?>> mapGenerics(Class<?> clazz) {
+    Type genericSuperclass = clazz.getGenericSuperclass();
+    if (!(genericSuperclass instanceof ParameterizedType)) {
+      return new HashMap<>();
+    }
+
+    ParameterizedType parameterized = (ParameterizedType) genericSuperclass;
+    TypeVariable<?>[] typeVars = ((Class<?>) parameterized.getRawType()).getTypeParameters();
+    Type[] actualTypes = parameterized.getActualTypeArguments();
+
+    Map<TypeVariable<?>, Class<?>> typeMap = new HashMap<>();
+    for (int i = 0; i < typeVars.length; i++) {
+      Type actual = actualTypes[i];
+      Class<?> resolvedClass = resolveToClass(actual);
+      if (resolvedClass != null) {
+        typeMap.put(typeVars[i], resolvedClass);
+      } else {
+        // ignore
+      }
+    }
+    return typeMap;
+  }
+
+  private static Class<?> resolveToClass(Type type) {
+    if (type instanceof Class<?>) {
+      return (Class<?>) type;
+    } else if (type instanceof ParameterizedType) {
+      ParameterizedType pType = (ParameterizedType) type;
+      Type raw = pType.getRawType();
+      if (raw instanceof Class<?>) {
+        return (Class<?>) raw;
+      }
+    }
+    return null;
+  }
 }

ebean-querybean/src/test/java/org/example/domain/GenericBaseModel.java

@@ -0,0 +1,69 @@
+package org.example.domain;
+
+import io.ebean.Model;
+import io.ebean.annotation.WhenCreated;
+import io.ebean.annotation.WhenModified;
+
+import jakarta.persistence.Id;
+import jakarta.persistence.MappedSuperclass;
+import jakarta.persistence.Version;
+import java.sql.Timestamp;
+
+/**
+ * Base domain object with Id, version, whenCreated and whenUpdated.
+ *
+ * <p>
+ * Extending Model to enable the 'active record' style.
+ *
+ * <p>
+ * whenCreated and whenUpdated are generally useful for maintaining external search services (like
+ * elasticsearch) and audit.
+ */
+@MappedSuperclass
+public abstract class GenericBaseModel<T> extends Model {
+
+  @Id
+  T id;
+
+  @Version
+  Long version;
+
+  @WhenCreated
+  Timestamp whenCreated;
+
+  @WhenModified
+  Timestamp whenUpdated;
+
+  public T getId() {
+    return id;
+  }
+
+  public void setId(T id) {
+    this.id = id;
+  }
+
+  public Long getVersion() {
+    return version;
+  }
+
+  public void setVersion(Long version) {
+    this.version = version;
+  }
+
+  public Timestamp getWhenCreated() {
+    return whenCreated;
+  }
+
+  public void setWhenCreated(Timestamp whenCreated) {
+    this.whenCreated = whenCreated;
+  }
+
+  public Timestamp getWhenUpdated() {
+    return whenUpdated;
+  }
+
+  public void setWhenUpdated(Timestamp whenUpdated) {
+    this.whenUpdated = whenUpdated;
+  }
+
+}

ebean-querybean/src/test/java/org/example/domain/ProductWithGenericLong.java

@@ -0,0 +1,48 @@
+package org.example.domain;
+
+import org.example.domain.ProductWithGenericLong;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Table;
+import javax.validation.constraints.Size;
+
+/**
+ * Product entity bean.
+ */
+@Entity
+@Table(name = "long_product", schema = "foo")
+public class ProductWithGenericLong extends GenericBaseModel<Long> {
+
+  @Size(max = 20)
+  String sku;
+
+  String name;
+
+  /**
+   * Return sku.
+   */
+  public String getSku() {
+    return sku;
+  }
+
+  /**
+   * Set sku.
+   */
+  public void setSku(String sku) {
+    this.sku = sku;
+  }
+
+  /**
+   * Return name.
+   */
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set name.
+   */
+  public void setName(String name) {
+    this.name = name;
+  }
+
+}

ebean-querybean/src/test/java/org/example/domain/ProductWithGenericString.java

@@ -0,0 +1,48 @@
+package org.example.domain;
+
+import org.example.domain.ProductWithGenericLong;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Table;
+import javax.validation.constraints.Size;
+
+/**
+ * Product entity bean.
+ */
+@Entity
+@Table(name = "string_product", schema = "foo")
+public class ProductWithGenericString extends GenericBaseModel<String> {
+
+  @Size(max = 20)
+  String sku;
+
+  String name;
+
+  /**
+   * Return sku.
+   */
+  public String getSku() {
+    return sku;
+  }
+
+  /**
+   * Set sku.
+   */
+  public void setSku(String sku) {
+    this.sku = sku;
+  }
+
+  /**
+   * Return name.
+   */
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set name.
+   */
+  public void setName(String name) {
+    this.name = name;
+  }
+
+}

ebean-querybean/src/test/java/org/querytest/QProductWithGenericTest.java

@@ -0,0 +1,49 @@
+package org.querytest;
+
+import io.ebean.InTuples;
+
+import org.example.domain.ProductWithGenericLong;
+import org.example.domain.ProductWithGenericString;
+import org.example.domain.query.QContact;
+import org.example.domain.query.QProductWithGenericLong;
+import org.example.domain.query.QProductWithGenericString;
+import org.junit.jupiter.api.Test;
+
+import java.time.ZonedDateTime;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class QProductWithGenericTest {
+
+  @Test
+  void findByLongId() {
+
+    var entity = new ProductWithGenericLong();
+    entity.setId(42L);
+    entity.setName("Gadget");
+    entity.save();
+
+    var result = new QProductWithGenericLong()
+      .id.eq(42L)
+      .findOne();
+
+    assertThat(result).isNotNull();
+    assertThat(result.getName()).isEqualTo("Gadget");
+  }
+
+  @Test
+  void findByStringId() {
+
+    var entity = new ProductWithGenericString();
+    entity.setId("1234");
+    entity.setName("Gadget");
+    entity.save();
+
+    var result = new QProductWithGenericString()
+      .id.eq("1234")
+      .findOne();
+
+    assertThat(result).isNotNull();
+    assertThat(result.getName()).isEqualTo("Gadget");
+  }
+}