HHH-8885 MapJoin.key() produces unusable Path object

hibernate-entitymanager/src/main/java/org/hibernate/jpa/criteria/path/MapKeyHelpers.java

@@ -36,8 +36,10 @@ import javax.persistence.metamodel.MapAttribute;
 import javax.persistence.metamodel.SingularAttribute;
 import javax.persistence.metamodel.Type;
 
+import org.hibernate.jpa.criteria.compile.RenderingContext;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.jpa.criteria.CriteriaBuilderImpl;
+import org.hibernate.jpa.criteria.PathSource;
 import org.hibernate.jpa.criteria.MapJoinImplementor;
 import org.hibernate.jpa.criteria.PathImplementor;
 import org.hibernate.persister.collection.CollectionPersister;
@@ -109,6 +111,20 @@ public class MapKeyHelpers {
 			// todo : if key is an entity, this is probably not enough
 			return (MapKeyPath<T>) this;
 		}
+
+		@Override
+		public String render(RenderingContext renderingContext) {
+			PathSource<?> source = getPathSource();
+			String name;
+			if ( source != null ) {
+				source.prepareAlias( renderingContext );
+				name = source.getPathIdentifier();
+			}
+			else {
+				name = getAttribute().getName();
+			}
+			return "key(" + name + ")";
+		}
 	}
 
 	/**
@@ -164,6 +180,12 @@ public class MapKeyHelpers {
 		public <T extends Map<K, V>> PathImplementor<T> treatAs(Class<T> treatAsType) {
 			throw new UnsupportedOperationException();
 		}
+
+		@Override
+		public String getPathIdentifier() {
+			return mapJoin.getPathIdentifier();
+		}
+
 	}
 
 	/**

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/criteria/mapjoin/MapJoinTest.java

@@ -0,0 +1,45 @@
+package org.hibernate.jpa.test.criteria.mapjoin;
+
+import javax.persistence.EntityManager;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.MapJoin;
+import javax.persistence.criteria.Root;
+
+import org.hibernate.jpa.test.metamodel.AbstractMetamodelSpecificTest;
+import org.hibernate.jpa.test.metamodel.MapEntity;
+import org.hibernate.jpa.test.metamodel.MapEntityLocal;
+import org.hibernate.jpa.test.metamodel.MapEntityLocal_;
+import org.hibernate.jpa.test.metamodel.MapEntity_;
+import org.junit.Test;
+
+public class MapJoinTest extends AbstractMetamodelSpecificTest {
+
+	@Override
+	public Class[] getAnnotatedClasses() {
+		return new Class[] { MapEntity.class, MapEntityLocal.class };
+	}
+	@Test
+	public void allEntities() {
+		EntityManager em = getOrCreateEntityManager();
+		em.getTransaction().begin();
+		
+		CriteriaBuilder cb = em.getCriteriaBuilder();
+		CriteriaQuery<MapEntity> query = cb.createQuery(MapEntity.class);
+
+		Root<MapEntity> entity = query.from(MapEntity.class);
+		MapJoin<MapEntity, String, MapEntityLocal> cname = entity.join(MapEntity_.localized);
+		
+		query = query
+			.select(entity)
+			.where( 
+				cb.equal( cname.key(), "en" ) 
+			)
+			.orderBy( cb.asc( cb.upper( cname.value().get(MapEntityLocal_.shortName) ) ) );
+		
+		em.createQuery(query).getResultList();
+		
+		em.getTransaction().commit();
+		em.close();
+	}
+}

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/metamodel/MapEntity.java

@@ -0,0 +1,35 @@
+package org.hibernate.jpa.test.metamodel;
+
+import java.util.Map;
+
+import javax.persistence.CollectionTable;
+import javax.persistence.Column;
+import javax.persistence.ElementCollection;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.MapKeyColumn;
+import javax.persistence.Table;
+
+@Entity
+@Table( name = "MAP_ENTITY" )
+public class MapEntity {
+
+	@Id
+	@Column(name="key_")
+	private String key;
+	
+	@ElementCollection(fetch=FetchType.LAZY)
+	@CollectionTable(name="MAP_ENTITY_NAME", joinColumns=@JoinColumn(name="key_"))
+	@MapKeyColumn(name="lang_")
+	private Map<String, MapEntityLocal> localized;
+	
+	public String getKey() {
+		return key;
+	}
+	
+	public void setKey(String key) {
+		this.key = key;
+	}
+}

hibernate-entitymanager/src/test/java/org/hibernate/jpa/test/metamodel/MapEntityLocal.java

@@ -0,0 +1,19 @@
+package org.hibernate.jpa.test.metamodel;
+
+import javax.persistence.Column;
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class MapEntityLocal {
+	
+	@Column(name="short_name") 
+	private String shortName;
+	
+	public String getShortName() {
+		return shortName;
+	}
+	
+	public void setShortName(String shortName) {
+		this.shortName = shortName;
+	}
+}