Support GORM domain inheritance with Groovy 4: convert GormEntityApi to Groovy trait

Closes gh-26

Author: rainboyan

grace-datastore-gorm/src/main/groovy/org/grails/datastore/gorm/GormEntityApi.groovy

@@ -3,67 +3,72 @@ package org.grails.datastore.gorm
 /**
  * API for instance methods defined by a GORM entity
  *
+ * To use GORM domain inheritance with Groovy 4, {@link GormEntityApi} should be converted to a `Trait,
+ *
+ * https://issues.apache.org/jira/browse/GROOVY-5106
+ * https://issues.apache.org/jira/browse/GROOVY-11508
+ *
  * @author Graeme Rocher
  * @since 5.0.5
  *
  * @param <D> The entity type
  */
-interface GormEntityApi<D> {
+trait GormEntityApi<D> {
 
     /**
      * Proxy aware instanceOf implementation.
      */
-    boolean instanceOf(Class cls)
+    abstract boolean instanceOf(Class cls)
 
     /**
      * Upgrades an existing persistence instance to a write lock
      * @return The instance
      */
-    D lock()
+    abstract D lock()
 
     /**
      * Locks the instance for updates for the scope of the passed closure
      *
      * @param callable The closure
      * @return The result of the closure
      */
-    def mutex(Closure callable)
+    abstract def mutex(Closure callable)
 
     /**
      * Refreshes the state of the current instance
      * @return The instance
      */
-    D refresh()
+    abstract D refresh()
 
     /**
      * Saves an object the datastore
      * @return Returns the instance
      */
-    D save()
+    abstract D save()
 
     /**
      * Forces an insert of an object to the datastore
      * @return Returns the instance
      */
-    D insert()
+    abstract D insert()
 
     /**
      * Forces an insert of an object to the datastore
      * @return Returns the instance
      */
-    D insert(Map params)
+    abstract D insert(Map params)
 
     /**
      * Saves an object the datastore
      * @return Returns the instance
      */
-    D merge()
+    abstract D merge()
 
     /**
      * Saves an object the datastore
      * @return Returns the instance
      */
-    D merge(Map params)
+    abstract D merge(Map params)
 
     /**
      * Save method that takes a boolean which indicates whether to perform validation or not
@@ -72,46 +77,46 @@ interface GormEntityApi<D> {
      *
      * @return The instance or null if validation fails
      */
-    D save(boolean validate)
+    abstract D save(boolean validate)
 
     /**
      * Saves an object with the given parameters
      * @param instance The instance
      * @param params The parameters
      * @return The instance
      */
-    D save(Map params)
+    abstract D save(Map params)
 
     /**
      * Returns the objects identifier
      */
-    Serializable ident()
+    abstract Serializable ident()
 
     /**
      * Attaches an instance to an existing session. Requries a session-based model
      * @return
      */
-    D attach()
+    abstract D attach()
 
     /**
      * No concept of session-based model so defaults to true
      */
-    boolean isAttached()
+    abstract boolean isAttached()
 
     /**
      * Discards any pending changes. Requires a session-based model.
      */
-    void discard()
+    abstract void discard()
 
     /**
      * Deletes an instance from the datastore
      */
-    void delete()
+    abstract void delete()
 
     /**
      * Deletes an instance from the datastore
      */
-    void delete(Map params)
+    abstract void delete(Map params)
 
     /**
      * Checks whether a field is dirty
@@ -121,14 +126,14 @@ interface GormEntityApi<D> {
      *
      * @return true if the field is dirty
      */
-    boolean isDirty(String fieldName)
+    abstract boolean isDirty(String fieldName)
 
     /**
      * Checks whether an entity is dirty
      *
      * @param instance The instance
      * @return true if it is dirty
      */
-    boolean isDirty()
+    abstract boolean isDirty()
 
 }