#171 Implicitly create alias for inner sub-query

to avoid multiple conflicting this_ aliases.

Author: puneetbehl

grails-datastore-gorm-hibernate5/src/main/groovy/grails/orm/HibernateCriteriaBuilder.java

@@ -207,6 +207,10 @@ protected org.hibernate.criterion.DetachedCriteria convertToHibernateCriteria(Qu
 
     public static org.hibernate.criterion.DetachedCriteria getHibernateDetachedCriteria(AbstractHibernateQuery query, QueryableCriteria<?> queryableCriteria) {
         String alias = queryableCriteria.getAlias();
+        return getHibernateDetachedCriteria(query, queryableCriteria, alias);
+    }
+
+    public static org.hibernate.criterion.DetachedCriteria getHibernateDetachedCriteria(AbstractHibernateQuery query, QueryableCriteria<?> queryableCriteria, String alias) {
         PersistentEntity persistentEntity = queryableCriteria.getPersistentEntity();
         Class targetClass = persistentEntity.getJavaClass();
         org.hibernate.criterion.DetachedCriteria detachedCriteria;

grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/query/AbstractHibernateCriterionAdapter.java

@@ -36,6 +36,7 @@
 public abstract class AbstractHibernateCriterionAdapter {
     protected static final Map<Class<?>, CriterionAdaptor<?>> criterionAdaptors = new HashMap<Class<?>, CriterionAdaptor<?>>();
     protected static boolean initialized;
+    protected static final String ALIAS = "_alias";
 
     public AbstractHibernateCriterionAdapter() {
         initialize();
@@ -154,7 +155,12 @@ public Criterion toHibernateCriterion(AbstractHibernateQuery hibernateQuery, Que
         criterionAdaptors.put(Query.Exists.class, new CriterionAdaptor<Query.Exists>() {
             @Override
             public Criterion toHibernateCriterion(AbstractHibernateQuery hibernateQuery, Query.Exists criterion, String alias) {
-                DetachedCriteria detachedCriteria = toHibernateDetachedCriteria(hibernateQuery,criterion.getSubquery());
+                final QueryableCriteria subquery = criterion.getSubquery();
+                String subqueryAlias = subquery.getAlias();
+                if (subquery.getAlias() == null) {
+                    subqueryAlias = criterion.getSubquery().getPersistentEntity().getJavaClass().getSimpleName() + ALIAS;
+                }
+                DetachedCriteria detachedCriteria = toHibernateDetachedCriteria(hibernateQuery,subquery, subqueryAlias);
                 return Subqueries.exists(detachedCriteria);
             }
         });
@@ -537,6 +543,10 @@ public org.hibernate.criterion.Criterion toHibernateCriterion(AbstractHibernateQ
 
     protected abstract org.hibernate.criterion.DetachedCriteria toHibernateDetachedCriteria(AbstractHibernateQuery query, QueryableCriteria<?> queryableCriteria);
 
+    protected org.hibernate.criterion.DetachedCriteria toHibernateDetachedCriteria(AbstractHibernateQuery query, QueryableCriteria<?> queryableCriteria, String alias) {
+        return toHibernateDetachedCriteria(query, queryableCriteria);
+    }
+
     public static abstract class CriterionAdaptor<T extends Query.Criterion> {
         public abstract org.hibernate.criterion.Criterion toHibernateCriterion(AbstractHibernateQuery hibernateQuery, T criterion, String alias);
 

grails-datastore-gorm-hibernate5/src/main/groovy/org/grails/orm/hibernate/query/HibernateCriterionAdapter.java

@@ -37,4 +37,12 @@ protected Criterion createRlikeExpression(String propertyName, String pattern) {
     protected DetachedCriteria toHibernateDetachedCriteria(AbstractHibernateQuery hibernateQuery, QueryableCriteria<?> queryableCriteria) {
         return HibernateCriteriaBuilder.getHibernateDetachedCriteria(hibernateQuery, queryableCriteria);
     }
+
+    @Override
+    protected DetachedCriteria toHibernateDetachedCriteria(AbstractHibernateQuery hibernateQuery, QueryableCriteria<?> queryableCriteria, String alias) {
+        if (alias == null) {
+            return toHibernateDetachedCriteria(hibernateQuery, queryableCriteria);
+        }
+        return HibernateCriteriaBuilder.getHibernateDetachedCriteria(hibernateQuery, queryableCriteria, alias);
+    }
 }