[wip] Fix Envers compatibility with ImmutableType

Envers expects (simple) audited types to implement the BasicType
interface. This commit changes The ImmutableType to implement BasicType
rather than Type.

The commit is work in progress: It only applies the change to
hibernate-types-55 as a template. If the change is OK, it will be
applied to other hibernate-types-* as well.

Resolves: vladmihalcea#463

hibernate-types-55/pom.xml

@@ -24,6 +24,13 @@
             <scope>provided</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.hibernate</groupId>
+            <artifactId>hibernate-envers</artifactId>
+            <version>${hibernate.version}</version>
+            <scope>test</scope>
+        </dependency>
+
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>

hibernate-types-55/src/main/java/com/vladmihalcea/hibernate/type/HibernateTypesContributor.java

@@ -101,13 +101,13 @@ private HibernateTypesContributor contributeType(TypeContributions typeContribut
         return this;
     }
 
+    private HibernateTypesContributor contributeType(TypeContributions typeContributions, ImmutableType<?> type) {
+        typeContributions.contributeType(type);
+        return this;
+    }
+
     private HibernateTypesContributor contributeType(TypeContributions typeContributions, UserType type) {
-        if(type instanceof ImmutableType) {
-            ImmutableType immutableType = (ImmutableType) type;
-            typeContributions.contributeType(immutableType, immutableType.getName());
-        } else {
-            typeContributions.contributeType(type, type.getClass().getSimpleName());
-        }
+        typeContributions.contributeType(type, type.getClass().getSimpleName());
         return this;
     }
 }

hibernate-types-55/src/main/java/com/vladmihalcea/hibernate/type/ImmutableType.java

@@ -8,10 +8,10 @@
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.internal.util.collections.ArrayHelper;
+import org.hibernate.type.BasicType;
 import org.hibernate.type.ForeignKeyDirection;
 import org.hibernate.type.Type;
 import org.hibernate.type.descriptor.java.IncomparableComparator;
-import org.hibernate.type.spi.TypeBootstrapContext;
 import org.hibernate.usertype.UserType;
 
 import java.io.Serializable;
@@ -29,7 +29,7 @@
  *
  * @author Vlad Mihalcea
  */
-public abstract class ImmutableType<T> implements UserType, Type {
+public abstract class ImmutableType<T> implements UserType, BasicType {
 
     private final Configuration configuration;
 
@@ -320,4 +320,9 @@ public Object replace(Object original, Object target, SharedSessionContractImple
     public boolean[] toColumnNullness(Object value, Mapping mapping) {
         return value == null ? ArrayHelper.FALSE : ArrayHelper.TRUE;
     }
+
+    @Override
+    public String[] getRegistrationKeys() {
+        return new String[]{getName()};
+    }
 }

hibernate-types-55/src/test/java/com/vladmihalcea/hibernate/type/basic/PostgreSQLHStoreTypeTest.java

@@ -5,6 +5,7 @@
 import org.hibernate.annotations.NaturalId;
 import org.hibernate.annotations.Type;
 import org.hibernate.annotations.TypeDef;
+import org.hibernate.envers.Audited;
 import org.junit.Test;
 
 import javax.persistence.*;
@@ -67,6 +68,7 @@ public void test() {
         });
     }
 
+    @Audited
     @Entity(name = "Book")
     @Table(name = "book")
     @TypeDef(name = "hstore", typeClass = PostgreSQLHStoreType.class)