Investigate allowing an entity to extend entity ( ~"Customization" )

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

@@ -119,6 +119,7 @@ public final class BeanDescriptorManager implements BeanDescriptorMap, SpiBeanTy
   private Map<Class<?>, DeployBeanInfo<?>> deployInfoMap = new HashMap<>();
   private Set<Class<?>> embeddedIdTypes = new HashSet<>();
   private List<DeployBeanInfo<?>> embeddedBeans = new ArrayList<>();
+  private final List<CustomPair> customizedEntities = new ArrayList<>();
 
   /**
    * Create for a given database dbConfig.
@@ -511,6 +512,11 @@ private void initialiseAll() {
         checkForValidEmbeddedId(d);
       }
     }
+    //for (CustomPair pair : customizedEntities) {
+      //BeanManager<?> newDesc = beanManagerMap.get(pair.overrideType.getName());
+      //BeanManager<?> oldDesc = beanManagerMap.get(pair.originalType.getName());
+      // System.out.println("replaced " + oldDesc + " with " + newDesc);
+    //}
   }
 
   private void checkForValidEmbeddedId(BeanDescriptor<?> d) {
@@ -618,7 +624,16 @@ public <T> DeployBeanInfo<T> deploy(Class<T> cls) {
 
   private void registerDescriptor(DeployBeanInfo<?> info) {
     BeanDescriptor<?> desc = new BeanDescriptor<>(this, info.getDescriptor());
+    if (info.isCustomized()) {
+      // register for persisting via BeanManager which will use this descriptor
+      descMap.put("customized:" + desc.type().getName(), desc);
+      return;
+    }
     descMap.put(desc.type().getName(), desc);
+    Class<?> originalType = info.getOriginalType();
+    if (originalType != null) {
+      descMap.put(originalType.getName(), desc);
+    }
     if (desc.isDocStoreMapped()) {
       descQueueMap.put(desc.docStoreQueueId(), desc);
     }
@@ -657,6 +672,10 @@ private void readEntityDeploymentInitial() {
         embeddedBeans.add(info);
       }
     }
+    for (CustomPair pair : customizedEntities) {
+      DeployBeanInfo<?> info = deployInfoMap.get(pair.originalType);
+      info.markAsCustomized();
+    }
   }
 
   private void registerEmbeddedBean(DeployBeanInfo<?> info) {
@@ -671,8 +690,14 @@ private void registerEmbeddedBean(DeployBeanInfo<?> info) {
    */
   private void readEntityBeanTable() {
     for (DeployBeanInfo<?> info : deployInfoMap.values()) {
-      BeanTable beanTable = createBeanTable(info);
-      beanTableMap.put(beanTable.getBeanType(), beanTable);
+      if (!info.isCustomized()) {
+        BeanTable beanTable = createBeanTable(info);
+        beanTableMap.put(beanTable.getBeanType(), beanTable);
+        Class<?> originalType = info.getOriginalType();
+        if (originalType != null) {
+          beanTableMap.put(originalType, beanTable);
+        }
+      }
     }
     // register non-id embedded beans (after bean tables are created)
     for (DeployBeanInfo<?> info : embeddedBeans) {
@@ -1506,6 +1531,13 @@ public List<MetaQueryPlan> queryPlanInit(QueryPlanInit request) {
     return list;
   }
 
+  /**
+   * Register that entity overrideType extends/customizes the originalType entity.
+   */
+  public void addCustomizedEntity(Class<?> overrideType, Class<?> originalType) {
+    customizedEntities.add(new CustomPair(overrideType, originalType));
+  }
+
   /**
    * Comparator to sort the BeanDescriptors by name.
    */
@@ -1518,4 +1550,15 @@ public int compare(BeanDescriptor<?> o1, BeanDescriptor<?> o2) {
       return o1.name().compareTo(o2.name());
     }
   }
+
+  private static final class CustomPair {
+
+    final Class<?> overrideType;
+    final Class<?> originalType;
+
+    CustomPair(Class<?> overrideType, Class<?> originalType) {
+      this.overrideType = overrideType;
+      this.originalType = originalType;
+    }
+  }
 }

ebean-core/src/main/java/io/ebeaninternal/server/deploy/meta/DeployBeanDescriptor.java

@@ -8,31 +8,14 @@
 import io.ebean.config.TableName;
 import io.ebean.config.dbplatform.IdType;
 import io.ebean.config.dbplatform.PlatformIdGenerator;
-import io.ebean.event.BeanFindController;
-import io.ebean.event.BeanPersistController;
-import io.ebean.event.BeanPersistListener;
-import io.ebean.event.BeanPostConstructListener;
-import io.ebean.event.BeanPostLoad;
-import io.ebean.event.BeanQueryAdapter;
+import io.ebean.event.*;
 import io.ebean.event.changelog.ChangeLogFilter;
 import io.ebean.text.PathProperties;
 import io.ebean.util.SplitName;
 import io.ebeaninternal.api.ConcurrencyMode;
 import io.ebeaninternal.server.core.CacheOptions;
 import io.ebeaninternal.server.deploy.BeanDescriptor.EntityType;
-import io.ebeaninternal.server.deploy.BeanDescriptorManager;
-import io.ebeaninternal.server.deploy.ChainedBeanPersistController;
-import io.ebeaninternal.server.deploy.ChainedBeanPersistListener;
-import io.ebeaninternal.server.deploy.ChainedBeanPostConstructListener;
-import io.ebeaninternal.server.deploy.ChainedBeanPostLoad;
-import io.ebeaninternal.server.deploy.ChainedBeanQueryAdapter;
-import io.ebeaninternal.server.deploy.DeployPropertyParserMap;
-import io.ebeaninternal.server.deploy.IdentityMode;
-import io.ebeaninternal.server.deploy.IndexDefinition;
-import io.ebeaninternal.server.deploy.InheritInfo;
-import io.ebeaninternal.server.deploy.PartitionMeta;
-import io.ebeaninternal.server.deploy.TableJoin;
-import io.ebeaninternal.server.deploy.TablespaceMeta;
+import io.ebeaninternal.server.deploy.*;
 import io.ebeaninternal.server.deploy.parse.DeployBeanInfo;
 import io.ebeaninternal.server.idgen.UuidV1IdGenerator;
 import io.ebeaninternal.server.idgen.UuidV1RndIdGenerator;
@@ -41,13 +24,7 @@
 
 import javax.persistence.Entity;
 import javax.persistence.MappedSuperclass;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 /**
  * Describes Beans including their deployment information.
@@ -118,6 +95,8 @@ public int compare(DeployBeanProperty o1, DeployBeanProperty o2) {
    * The EntityBean type used to create new EntityBeans.
    */
   private final Class<T> beanType;
+  private Class<?> originalType;
+  private boolean customized;
   private final List<BeanPersistController> persistControllers = new ArrayList<>();
   private final List<BeanPersistListener> persistListeners = new ArrayList<>();
   private final List<BeanQueryAdapter> queryAdapters = new ArrayList<>();
@@ -254,7 +233,7 @@ public PartitionMeta getPartitionMeta() {
     }
     return partitionMeta;
   }
-  
+
   public void setTablespaceMeta(TablespaceMeta tablespaceMeta) {
     this.tablespaceMeta = tablespaceMeta;
   }
@@ -312,11 +291,9 @@ public boolean isScalaObject() {
   }
 
   public DeployBeanTable createDeployBeanTable() {
-
-    DeployBeanTable beanTable = new DeployBeanTable(getBeanType());
+    DeployBeanTable beanTable = new DeployBeanTable(beanType);
     beanTable.setBaseTable(baseTable);
     beanTable.setIdProperty(idProperty());
-
     return beanTable;
   }
 
@@ -392,6 +369,20 @@ public void setProperties(String[] props) {
     this.properties = props;
   }
 
+  public boolean isCustomized() {
+    return customized;
+  }
+
+  public void markAsCustomized() {
+    this.customized = true;
+    this.entityType = EntityType.VIEW;
+    this.dependentTables = new String[]{baseTable};
+  }
+
+  public Class<?> getOriginalType() {
+    return originalType;
+  }
+
   /**
    * Return the class type this BeanDescriptor describes.
    */
@@ -976,15 +967,18 @@ public void checkInheritanceMapping() {
    * Check valid mapping annotations on the class hierarchy.
    */
   private void checkInheritance(Class<?> beanType) {
-
     Class<?> parent = beanType.getSuperclass();
     if (parent == null || Object.class.equals(parent)) {
       // all good
       return;
     }
     if (parent.isAnnotationPresent(Entity.class)) {
-      String msg = "Checking " + getBeanType() + " and found " + parent + " that has @Entity annotation rather than MappedSuperclass?";
-      throw new IllegalStateException(msg);
+      // String msg = "Checking " + getBeanType() + " and found " + parent + " that has @Entity annotation rather than MappedSuperclass?";
+      // throw new IllegalStateException(msg);
+      // allow an entity to extend an entity ... as "customization"
+      originalType = parent;
+      manager.addCustomizedEntity(beanType, parent);
+      return;
     }
     if (parent.isAnnotationPresent(MappedSuperclass.class)) {
       // continue checking

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

@@ -77,4 +77,16 @@ public Class<?> getEmbeddedIdType() {
   public boolean isEmbedded() {
     return descriptor.isEmbedded();
   }
+
+  public Class<?> getOriginalType() {
+    return descriptor.getOriginalType();
+  }
+
+  public void markAsCustomized() {
+    descriptor.markAsCustomized();
+  }
+
+  public boolean isCustomized() {
+    return descriptor.isCustomized();
+  }
 }

ebean-test/src/test/java/org/tests/model/basic/cache/OCachedApp.java

@@ -3,10 +3,12 @@
 import io.ebean.annotation.Cache;
 
 import javax.persistence.Entity;
+import javax.persistence.Table;
 import javax.persistence.UniqueConstraint;
 
 @Cache(naturalKey = "appName")
 @Entity
+@Table(name="ocached_app")
 @UniqueConstraint(name="uq_ocached_app", columnNames = "app_name")
 public class OCachedApp extends OCacheBase {
 

ebean-test/src/test/java/org/tests/model/basic/cache/OCachedAppCustom.java

@@ -0,0 +1,28 @@
+package org.tests.model.basic.cache;
+
+import io.ebean.annotation.Cache;
+
+import javax.persistence.Entity;
+import javax.persistence.Table;
+import javax.persistence.UniqueConstraint;
+
+@Cache(naturalKey = "appName")
+@Entity
+@Table(name = "ocached_app")
+@UniqueConstraint(name = "uq_ocached_app", columnNames = "app_name")
+public class OCachedAppCustom extends OCachedApp {
+
+  String custom;
+
+  public OCachedAppCustom(String appName) {
+    super(appName);
+  }
+
+  public String getCustom() {
+    return custom;
+  }
+
+  public void setCustom(String custom) {
+    this.custom = custom;
+  }
+}

ebean-test/src/test/java/org/tests/model/basic/cache/TestCustomExtends.java

@@ -0,0 +1,35 @@
+package org.tests.model.basic.cache;
+
+import io.ebean.DB;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class TestCustomExtends {
+
+  @Test
+  void insert_find() {
+    OCachedApp orig = new OCachedApp("orig");
+    DB.save(orig);
+
+    OCachedAppCustom custom = new OCachedAppCustom("custom");
+    custom.setCustom("someCustomValue");
+    DB.save(custom);
+
+    OCachedAppCustom c1 = DB.find(OCachedAppCustom.class, custom.getId());
+    OCachedApp c2 = DB.find(OCachedApp.class, custom.getId());
+
+    OCachedAppCustom o1 = DB.find(OCachedAppCustom.class, orig.getId());
+    OCachedApp o2 = DB.find(OCachedApp.class, orig.getId());
+
+    assertThat(c1).isNotNull();
+    assertThat(c2).isNotNull();
+    assertThat(c2.getAppName()).isEqualTo(c1.getAppName());
+    assertThat(c2).isNotNull().isInstanceOf(OCachedAppCustom.class);
+
+    assertThat(o1).isNotNull();
+    assertThat(o2).isNotNull();
+    assertThat(o2.getAppName()).isEqualTo(o1.getAppName());
+    assertThat(o2).isNotNull().isInstanceOf(OCachedAppCustom.class);
+  }
+}