DATACMNS-866 - Improved error message in invalid invocations of BasicPersistentEntity.getPropertyAccessor(…).

We now explicitly report the given object's type and the one expected in case of a mismatch when BasicPersistentEntity.getPropertyAccessor(…) is invoked.

src/main/java/org/springframework/data/mapping/model/BasicPersistentEntity.java

@@ -58,6 +58,8 @@ import org.springframework.util.StringUtils;
  */
 public class BasicPersistentEntity<T, P extends PersistentProperty<P>> implements MutablePersistentEntity<T, P> {
 
+	private static final String TYPE_MISMATCH = "Target bean of type %s is not of type of the persistent entity (%s)!";
+
 	private final PreferredConstructor<T, P> constructor;
 	private final TypeInformation<T> information;
 	private final List<P> properties;
@@ -408,7 +410,9 @@ public class BasicPersistentEntity<T, P extends PersistentProperty<P>> implement
 	public PersistentPropertyAccessor getPropertyAccessor(Object bean) {
 
 		Assert.notNull(bean, "Target bean must not be null!");
-		Assert.isTrue(getType().isInstance(bean), "Target bean is not of type of the persistent entity!");
+
+		Assert.isTrue(getType().isInstance(bean),
+				String.format(TYPE_MISMATCH, bean.getClass().getName(), getType().getName()));
 
 		return propertyAccessorFactory.getPropertyAccessor(this, bean);
 	}

src/test/java/org/springframework/data/mapping/model/BasicPersistentEntityUnitTests.java

@@ -17,7 +17,7 @@ package org.springframework.data.mapping.model;
 
 import static org.hamcrest.CoreMatchers.*;
 import static org.junit.Assert.*;
-import static org.junit.Assume.assumeThat;
+import static org.junit.Assume.*;
 import static org.mockito.Mockito.*;
 
 import java.lang.annotation.Retention;
@@ -261,6 +261,20 @@ public class BasicPersistentEntityUnitTests<T extends PersistentProperty<T>> {
 		assertThat(entity.getTypeAlias(), is((Object) "bar"));
 	}
 
+	/**
+	 * @see DATACMNS-866
+	 */
+	@Test
+	public void invalidBeanAccessCreatesDescriptiveErrorMessage() {
+
+		PersistentEntity<Entity, T> entity = createEntity(Entity.class);
+
+		exception.expectMessage(Entity.class.getName());
+		exception.expectMessage(Object.class.getName());
+
+		entity.getPropertyAccessor(new Object());
+	}
+
 	private <S> BasicPersistentEntity<S, T> createEntity(Class<S> type) {
 		return createEntity(type, null);
 	}