[#679] Add support for getting entity reference fro entity view and f…

…ix support for spring data domain events

CHANGELOG.md

@@ -13,14 +13,18 @@ Not yet released
 * Support for binding associations mapped by compound or foreign keys
 * Using a comparator with `List` and `Collection` types in entity views will sort the collection after load
 * Add option to force deduplication of elements in non-sets to `@CollectionMapping`
-* Support `VALUES` clause with embeddable and most basic types
+* Support plain `VALUES` clause with embeddable and most basic types
 * Support for binding embeddable parameters in CTEs, insert and update queries
 * Properly implement dirty state transfer when converting one entity view to another
 * Added validation for `equals`/`hashCode` implementations of JPA managed types that are used within entity views which can be disabled with the property `com.blazebit.persistence.view.managed_type_validation_disabled`
 * Add support for DeltaSpike Data 1.9
 * Make use of Collection DML API when using the `QUERY` flush strategy in updatable entity views
 * Automatic embeddable splitting within `GROUP BY` clause to avoid Hibernate bugs
 * Support for entity view attribute filters and sorters on attributes of inheritance subtypes
+* Introduced new method `EntityViewManager.getEntityReference()` to get an entity reference by an entity view object
+* Allow to specify example attribute for `VALUES` clause for exact SQL types
+* Implemented creatability validation for creatable entity views
+* Implemented `SET_NULL` inverse remove strategy validation for updatable entity views
 
 ### Bug fixes
 
@@ -39,7 +43,7 @@ Not yet released
 
 ### Backwards-incompatible changes
 
-None yet
+* Require `@AllowUpdatableEntityViews` to be able to use updatable entity view types by for *ToOne relationships in updatable entity views to avoid [possible problems](https://persistence.blazebit.com/documentation/entity-view/manual/en_US/index.html#updatable-mappings-subview)
 
 ## 1.3.0-Alpha3
 

core/impl/src/main/java/com/blazebit/persistence/impl/JoinManager.java

@@ -326,7 +326,7 @@ private void visitKeyOrIndexExpression(PathExpression pathExpression) {
             JoinNode node = (JoinNode) pathExpression.getBaseNode();
             Attribute<?, ?> attribute = node.getParentTreeNode().getAttribute();
             // Exclude element collections as they are not problematic
-            if (jpaProvider.getJpaMetamodelAccessor().isElementCollection(attribute)) {
+            if (!jpaProvider.getJpaMetamodelAccessor().isElementCollection(attribute)) {
                 // There are weird mappings possible, we have to check if the attribute is a join table
                 if (jpaProvider.getJoinTable(node.getParent().getEntityType(), attribute.getName()) != null) {
                     keyRestrictedLeftJoins.add(node);

core/impl/src/main/java/com/blazebit/persistence/impl/util/SqlUtils.java

@@ -511,7 +511,7 @@ public static int findJoinStartIndex(CharSequence sqlSb, int tokenEnd, Set<JoinT
         do {
             tokenRange = SqlUtils.rtrimBackwardsToFirstWhitespace(sqlSb, tokenEnd);
             tokenEnd = tokenRange[0] - 1;
-            JoinToken token = JoinToken.valueOf(sqlSb.subSequence(tokenRange[0], tokenRange[1]).toString().trim().toUpperCase());
+            JoinToken token = JoinToken.of(sqlSb.subSequence(tokenRange[0], tokenRange[1]).toString().trim().toUpperCase());
             if (allowedTokens.contains(token)) {
                 allowedTokens = token.previous();
             } else {
@@ -527,6 +527,7 @@ public static int findJoinStartIndex(CharSequence sqlSb, int tokenEnd, Set<JoinT
      * @since 1.3.0
      */
     enum JoinToken {
+        COMMA,
         LEFT,
         INNER,
         RIGHT,
@@ -547,6 +548,15 @@ Set<JoinToken> previous() {
         Set<JoinToken> previous() {
             return EnumSet.noneOf(JoinToken.class);
         }
+
+        static JoinToken of(String text) {
+            switch (text) {
+                case ",":
+                    return COMMA;
+                default:
+                    return valueOf(text);
+            }
+        }
     }
 
     public static int findEndOfOnClause(CharSequence sqlSb, int predicateStartIndex, int whereIndex) {
@@ -558,6 +568,7 @@ public static int findEndOfOnClause(CharSequence sqlSb, int predicateStartIndex,
             end = findJoinStartIndex(sqlSb, joinIndex, JoinToken.JOIN.previous());
         }
         int potentialEndIndex = end;
+        int parenthesis = 0;
         QuoteMode mode = QuoteMode.NONE;
         for (int i = predicateStartIndex; i < end; i++) {
             char c = sqlSb.charAt(i);
@@ -567,7 +578,9 @@ public static int findEndOfOnClause(CharSequence sqlSb, int predicateStartIndex,
                 if (c == '(') {
                     // While we are in a subcontext, consider the whole query
                     end = whereIndex;
+                    parenthesis++;
                 } else if (c == ')') {
+                    parenthesis--;
                     // When we leave the context, reset the end to the potential end index
                     if (i < potentialEndIndex) {
                         end = potentialEndIndex;
@@ -581,6 +594,9 @@ public static int findEndOfOnClause(CharSequence sqlSb, int predicateStartIndex,
                             end = potentialEndIndex = findJoinStartIndex(sqlSb, joinIndex, JoinToken.JOIN.previous());
                         }
                     }
+                } else if (c == ',' && parenthesis == 0) {
+                    // Cross join via comma operator
+                    return i;
                 }
             }
         }

core/testsuite/src/test/java/com/blazebit/persistence/testsuite/GroupByTest.java

@@ -18,6 +18,7 @@
 
 import com.blazebit.persistence.CriteriaBuilder;
 import com.blazebit.persistence.testsuite.base.jpa.category.NoDatanucleus;
+import com.blazebit.persistence.testsuite.base.jpa.category.NoDatanucleus4;
 import com.blazebit.persistence.testsuite.base.jpa.category.NoFirebird;
 import com.blazebit.persistence.testsuite.base.jpa.category.NoH2;
 import com.blazebit.persistence.testsuite.base.jpa.category.NoMySQL;
@@ -138,6 +139,8 @@ public void testGroupByElementCollectionKey() {
     }
 
     @Test
+    // DataNucleus4 apparently can't handle join of associations within element collections
+    @Category({ NoDatanucleus4.class })
     public void testGroupByElementCollectionValue() {
         CriteriaBuilder<Long> cb = cbf.create(em, Long.class)
                 .from(Document.class, "d")

core/testsuite/src/test/java/com/blazebit/persistence/testsuite/ValuesClauseTest.java

@@ -134,7 +134,8 @@ public void testValuesEntityFunctionWithEmbeddable() {
     }
 
     @Test
-    @Category({ NoDatanucleus.class, NoEclipselink.class, NoOpenJPA.class })
+    // NOTE: Only the latest Hibernate 5.2 properly implements support for selecting element collections
+    @Category({ NoHibernate42.class, NoHibernate43.class, NoHibernate50.class, NoHibernate51.class, NoDatanucleus.class, NoEclipselink.class, NoOpenJPA.class })
     public void testValuesEntityFunctionWithPluralOnlyEmbeddable() {
         CriteriaBuilder<Tuple> cb = cbf.create(em, Tuple.class);
         cb.fromValues(NameObjectContainer.class, "embeddable", Collections.singleton(new NameObjectContainer("test", new NameObject("abc", "123"))));
@@ -253,7 +254,8 @@ public void testValuesEntityFunctionLikePluralBasic() {
     }
 
     @Test
-    @Category({ NoDatanucleus.class, NoEclipselink.class, NoOpenJPA.class })
+    // NOTE: Only the latest Hibernate 5.2 properly implements support for selecting element collections
+    @Category({ NoHibernate42.class, NoHibernate43.class, NoHibernate50.class, NoHibernate51.class, NoDatanucleus.class, NoEclipselink.class, NoOpenJPA.class })
     public void testValuesEntityFunctionLikePluralEmbeddable() {
         CriteriaBuilder<Tuple> cb = cbf.create(em, Tuple.class);
         cb.fromValues(Document.class, "names", "t", Collections.singleton(new NameObject("123", "abc")));

documentation/src/main/asciidoc/entity-view/manual/en_US/07_querying_and_pagination_api.adoc

@@ -24,6 +24,28 @@ Allowing the actual data consumer i.e. the UI to specify these aspects is essent
 For a simple lookup by id there is also a convenience link:{entity_view_jdoc}/persistence/view/EntityViewManager.html#find(javax.persistence.EntityManager,%20java.lang.Class,%20java.lang.Object)[`EntityViewManager.find()`] method available
 that allows you to skip some of the `CriteriaBuilder` ceremony and that works analogous to how `EntityManager.find()` works, but with entity views.
 
+[source, java]
+----
+CatView cat = entityViewManager.find(entityManager, CatView.class, catId);
+----
+
+To get just a _reference_ to an entity view similar to what an entity reference retrieved via `EntityManager.getReference()` represents, it is possible to use link:{entity_view_jdoc}/persistence/view/EntityViewManager.html#getReference(%20java.lang.Class,%20java.lang.Object)[`EntityViewManager.getReference()`].
+Note that the returned object will only have the identifier set, all other attributes will have their default values. This is usually useful when wanting to compare a list of elements with some entity view type against an entity id
+or also for setting *ToOne relationships.
+
+[source, java]
+----
+CatView cat = entityViewManager.getReference(CatView.class, catId);
+----
+
+To get a _reference_ to an entity form an entity view one can use link:{entity_view_jdoc}/persistence/view/EntityViewManager.html#find(javax.persistence.EntityManager,%20java.lang.Object)[`EntityViewManager.getEntityReference()`]
+which will return the entity reference object retrieved via `EntityManager.getReference()` for the given entity view object.
+
+[source, java]
+----
+Cat cat = entityViewManager.<Cat>getEntityReference(entityManager, catView);
+----
+
 === Querying entity views
 
 Code in the presentation layer is intended to create an `EntityViewSetting` via the `create()` API and pass the entity view setting to a data access method.

documentation/src/main/asciidoc/entity-view/manual/en_US/16_faq.adoc

@@ -0,0 +1,39 @@
+== FAQ
+
+This section tries to cover some standard questions that often come up when introducing entity views or updatable entity views into a project
+as well as some common problems with explanations and possible solutions.
+
+=== Why do I get an optimistic lock exception when updating an updatable entity view?
+
+The `com.blazebit.persistence.view.OptimisticLockException` is very similar to the `javax.persistence.OptimisticLockException` and when thrown,
+it signals that an update isn't possible because of a change of an object that happened in the meantime. This can also happen when you do not use optimistic locking explicitly.
+
+==== If you try to update a non-existent entity
+
+When trying to update an entity that does not exist, the `EntityViewManager.update` operation will throw the `com.blazebit.persistence.view.OptimisticLockException`.
+
+* The entity could have been deleted in the meantime i.e. between loading the view and the update operation
+* The entity view causing the exception is the result of a wrong usage of `EntityViewManager.convert` as it is missing the `ConvertOption.CREATE_NEW`
+
+==== If you try to update a concurrently updated entity
+
+Either the entity was updated within the current transaction or within another transaction through a different mechanism or a different entity view object.
+If an update in a different transaction caused the exception, it is necessary to load the new version of the entity view and let the end-user enter the values to update again.
+By inspecting the change model of the old instance one can assist the user by copying over non-conflicting value changes and just highlight conflicting changes.
+
+If a previous update in the same transaction causes the exception, the code should be adapted to prevent this from happening or updating the version on the entity view accordingly.
+
+=== Why do I get a "could not invoke proxy constructor" exception when fetching entity views?
+
+Entity views are type checked for most parts, but there are some dynamic non-declarative parts that can't be type checked that might cause this runtime exception when using a wrong result.
+Usually, this happens when a `SubqueryProvider` or `CorrelationProvider` is in use. The implementations of these classes define the result type in a manner that is not type checkable.
+
+If a `SubqueryProvider` returns an integer via e.g. `select("1")` or `select("someIntAttribute")`, but the entity view attribute using the subquery provider uses a different type like e.g. `boolean`,
+constructing an instance of that entity view might fail when trying to interpret the integer as boolean with an `IllegalArgumentException` saying that types are incompatible.
+The obvious fix is to correct either the select item to return the correct type or the entity view attribute to declare the appropriate attribute type.
+In case of a subquery provider it is also possible to wrap the subquery into a more complex expression by using e.g. `@MappingSubquery(value = MyProvider.class, subqueryAlias = "subquery", expression = "CASE WHEN EXISTS subquery THEN true ELSE false END")`.
+
+A `CorrelationProvider` can fail in a similar manner as it defines the entity type it correlates via `correlate(SomeEntity.class)`.
+If the entity view attribute expects a different type that is not compatible, it will fail at runtime with an `IllegalArgumentException` saying that types are incompatible.
+If a correlation result is defined via `@MappingCorrelated(correlationResult = "someAttributeOfCorrelatedEntity")` the type of that expression must be compatible which can be another cause for an error.
+This problem can be fixed by adapting the correlation result expression, by changing the correlated entity in the correlation provider or by changing the declared attribute type.

documentation/src/main/asciidoc/entity-view/manual/en_US/index.adoc

@@ -43,4 +43,6 @@ include::13_deltaspike_data.adoc[]
 
 include::14_metamodel.adoc[]
 
-include::15_configuration.adoc[]
+include::15_configuration.adoc[]
+
+include::16_faq.adoc[]

entity-view/api/src/main/java/com/blazebit/persistence/view/EntityViewManager.java

@@ -74,6 +74,17 @@ public interface EntityViewManager {
      */
     public <T> T getReference(Class<T> entityViewClass, Object id);
 
+    /**
+     * Creates an entity reference for the given entity view and returns it.
+     *
+     * @param entityManager The entity manager to use for the entity reference
+     * @param entityView The entity view class for which to get the entity reference
+     * @param <T> The type of the entity class
+     * @return An entity reference for given entity view object
+     * @since 1.3.0
+     */
+    public <T> T getEntityReference(EntityManager entityManager, Object entityView);
+
     /**
      * Gives access to the change model of the entity view instance.
      *

entity-view/impl/src/main/java/com/blazebit/persistence/view/impl/EntityViewManagerImpl.java

@@ -54,10 +54,6 @@
 import com.blazebit.persistence.view.impl.accessor.AttributeAccessor;
 import com.blazebit.persistence.view.impl.accessor.EntityIdAttributeAccessor;
 import com.blazebit.persistence.view.impl.change.ViewChangeModel;
-import com.blazebit.persistence.view.impl.macro.EmbeddingViewJpqlMacro;
-import com.blazebit.persistence.view.impl.mapper.ViewMapper;
-import com.blazebit.persistence.view.impl.update.DefaultUpdateContext;
-import com.blazebit.persistence.view.impl.update.UpdateContext;
 import com.blazebit.persistence.view.impl.filter.ContainsFilterImpl;
 import com.blazebit.persistence.view.impl.filter.ContainsIgnoreCaseFilterImpl;
 import com.blazebit.persistence.view.impl.filter.EndsWithFilterImpl;
@@ -71,6 +67,8 @@
 import com.blazebit.persistence.view.impl.filter.StartsWithFilterImpl;
 import com.blazebit.persistence.view.impl.filter.StartsWithIgnoreCaseFilterImpl;
 import com.blazebit.persistence.view.impl.macro.DefaultViewRootJpqlMacro;
+import com.blazebit.persistence.view.impl.macro.EmbeddingViewJpqlMacro;
+import com.blazebit.persistence.view.impl.mapper.ViewMapper;
 import com.blazebit.persistence.view.impl.metamodel.ManagedViewTypeImplementor;
 import com.blazebit.persistence.view.impl.metamodel.MappingConstructorImpl;
 import com.blazebit.persistence.view.impl.metamodel.MetamodelBuildingContext;
@@ -82,8 +80,12 @@
 import com.blazebit.persistence.view.impl.proxy.MutableStateTrackable;
 import com.blazebit.persistence.view.impl.proxy.ProxyFactory;
 import com.blazebit.persistence.view.impl.type.DefaultBasicUserTypeRegistry;
+import com.blazebit.persistence.view.impl.update.DefaultUpdateContext;
 import com.blazebit.persistence.view.impl.update.EntityViewUpdater;
 import com.blazebit.persistence.view.impl.update.EntityViewUpdaterImpl;
+import com.blazebit.persistence.view.impl.update.SimpleUpdateContext;
+import com.blazebit.persistence.view.impl.update.UpdateContext;
+import com.blazebit.persistence.view.impl.update.flush.CompositeAttributeFlusher;
 import com.blazebit.persistence.view.metamodel.ManagedViewType;
 import com.blazebit.persistence.view.metamodel.MappingConstructor;
 import com.blazebit.persistence.view.metamodel.ViewType;
@@ -273,6 +275,20 @@ public <T> T getReference(Class<T> entityViewClass, Object id) {
         }
     }
 
+    @Override
+    public <T> T getEntityReference(EntityManager entityManager, Object view) {
+        if (!(view instanceof EntityViewProxy)) {
+            throw new IllegalArgumentException("Can't remove non entity view object: " + view);
+        }
+        UpdateContext context = new SimpleUpdateContext(this, entityManager);
+        EntityViewProxy proxy = (EntityViewProxy) view;
+        Class<?> entityViewClass = proxy.$$_getEntityViewClass();
+        ManagedViewTypeImplementor<?> viewType = metamodel.managedView(entityViewClass);
+        EntityViewUpdater updater = getUpdater(viewType, null, null, null);
+        Object entityId = ((CompositeAttributeFlusher) updater.getFullGraphNode()).getEntityIdCopy(context, proxy);
+        return (T) entityManager.getReference(proxy.$$_getJpaManagedClass(), entityId);
+    }
+
     @Override
     public <T> T create(Class<T> entityViewClass) {
         Constructor<T> constructor = (Constructor<T>) createConstructorCache.get(entityViewClass);