HHH-8627 Support EntityGraphs through JPA Query hints

hibernate-core/src/main/java/org/hibernate/annotations/QueryHints.java

@@ -117,5 +117,17 @@ private QueryHints() {
 	 * Accepts a {@link javax.persistence.LockModeType} or a {@link org.hibernate.LockMode}
 	 */
 	public static final String NATIVE_LOCKMODE = "org.hibernate.lockMode";
+
+	/**
+	 * Hint providing an EntityGraph.  With JPQL/HQL, the sole functionality is attribute nodes are treated as
+	 * FetchType.EAGER.  Laziness is not affected.
+	 */
+	public static final String FETCHGRAPH = "javax.persistence.fetchgraph";
+
+	/**
+	 * Hint providing an EntityGraph.  With JPQL/HQL, the sole functionality is attribute nodes are treated as
+	 * FetchType.EAGER.  Laziness is not affected.
+	 */
+	public static final String LOADGRAPH = "javax.persistence.loadgraph";
 
 }

hibernate-core/src/main/java/org/hibernate/engine/query/spi/EntityGraphQueryHint.java

@@ -0,0 +1,137 @@
+/* 
+ * Hibernate, Relational Persistence for Idiomatic Java
+ * 
+ * JBoss, Home of Professional Open Source
+ * Copyright 2013 Red Hat Inc. and/or its affiliates and other contributors
+ * as indicated by the @authors tag. All rights reserved.
+ * See the copyright.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License, v. 2.1.
+ * This program is distributed in the hope that it will be useful, but WITHOUT A
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ * You should have received a copy of the GNU Lesser General Public License,
+ * v.2.1 along with this distribution; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA  02110-1301, USA.
+ */
+package org.hibernate.engine.query.spi;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+import javax.persistence.AttributeNode;
+import javax.persistence.EntityGraph;
+import javax.persistence.Subgraph;
+
+import org.hibernate.QueryException;
+import org.hibernate.engine.internal.JoinSequence;
+import org.hibernate.hql.internal.ast.HqlSqlWalker;
+import org.hibernate.hql.internal.ast.tree.FromClause;
+import org.hibernate.hql.internal.ast.tree.FromElement;
+import org.hibernate.hql.internal.ast.tree.FromElementFactory;
+import org.hibernate.persister.collection.QueryableCollection;
+import org.hibernate.sql.JoinType;
+import org.hibernate.type.EntityType;
+import org.hibernate.type.Type;
+
+/**
+ * Encapsulates a JPA EntityGraph provided through a JPQL query hint.  Converts the fetches into a list of AST
+ * FromElements.  The logic is kept here as much as possible in order to make it easy to remove this in the future,
+ * once our AST is improved and this "hack" is no longer needed.
+ * 
+ * @author Brett Meyer
+ */
+public class EntityGraphQueryHint {
+
+	private final EntityGraph<?> originEntityGraph;
+
+	public EntityGraphQueryHint( EntityGraph<?> originEntityGraph ) {
+		this.originEntityGraph = originEntityGraph;
+	}
+
+	public List<FromElement> toFromElements(FromClause fromClause, HqlSqlWalker walker) {
+		// If a role already has an explicit fetch in the query, skip it in the graph.
+		Map<String, FromElement> explicitFetches = new HashMap<String, FromElement>();
+		Iterator iter = fromClause.getFromElements().iterator();
+		while ( iter.hasNext() ) {
+			final FromElement fromElement = ( FromElement ) iter.next();
+			if (fromElement.getRole() != null) {
+				explicitFetches.put( fromElement.getRole(), fromElement );
+			}
+		}
+
+		return getFromElements( originEntityGraph.getAttributeNodes(), fromClause.getFromElement(), fromClause,
+				walker, explicitFetches );
+	}
+
+	private List<FromElement> getFromElements(List attributeNodes, FromElement origin, FromClause fromClause,
+			HqlSqlWalker walker, Map<String, FromElement> explicitFetches) {
+		final List<FromElement> fromElements = new ArrayList<FromElement>();
+
+		for (Object obj : attributeNodes) {			
+			final AttributeNode<?> attributeNode = (AttributeNode<?>) obj;
+
+			final String attributeName = attributeNode.getAttributeName();
+			final String className = origin.getClassName();
+			final String role = className + "." + attributeName;
+
+			final String classAlias = origin.getClassAlias();
+
+			final String originTableAlias = origin.getTableAlias();
+
+			Type propertyType = origin.getPropertyType( attributeName, attributeName );
+
+			try {
+				FromElement fromElement = null;
+				if (!explicitFetches.containsKey( role )) {
+					if ( propertyType.isEntityType() ) {
+						final EntityType entityType = (EntityType) propertyType;
+
+						final String[] columns = origin.toColumns( originTableAlias, attributeName, false );
+						final String tableAlias = walker.getAliasGenerator().createName(
+								entityType.getAssociatedEntityName() );	
+
+						final FromElementFactory fromElementFactory = new FromElementFactory( fromClause, origin,
+								attributeName, classAlias, columns, false);
+						final JoinSequence joinSequence = walker.getSessionFactoryHelper().createJoinSequence(
+								false, entityType, tableAlias, JoinType.LEFT_OUTER_JOIN, columns );
+						fromElement = fromElementFactory.createEntityJoin( entityType.getAssociatedEntityName(), tableAlias,
+								joinSequence, true, walker.isInFrom(), entityType, role );
+					}
+					else if ( propertyType.isCollectionType() ) {					
+						final String[] columns = origin.toColumns( originTableAlias, attributeName, false );		
+
+						final FromElementFactory fromElementFactory = new FromElementFactory( fromClause, origin,
+								attributeName, classAlias, columns, false);
+						final QueryableCollection queryableCollection = walker.getSessionFactoryHelper()
+								.requireQueryableCollection( role );
+						fromElement = fromElementFactory.createCollection(
+								queryableCollection, role, JoinType.LEFT_OUTER_JOIN, true, false ) ;
+					}
+				}
+
+				if (fromElement != null) {
+					fromElements.add( fromElement );
+
+					// recurse into subgraphs
+					for (Subgraph<?> subgraph : attributeNode.getSubgraphs().values()) {
+						fromElements.addAll( getFromElements( subgraph.getAttributeNodes(), fromElement,
+								fromClause, walker, explicitFetches ) );
+					}
+				}
+			}
+			catch (Exception e) {
+				throw new QueryException( "Could not apply the EntityGraph to the Query!", e );
+			}
+		}
+
+		return fromElements;
+	}
+}

hibernate-core/src/main/java/org/hibernate/engine/query/spi/FilterQueryPlan.java

@@ -53,7 +53,7 @@ public FilterQueryPlan(
 			boolean shallow,
 			Map enabledFilters,
 			SessionFactoryImplementor factory) {
-		super( hql, collectionRole, shallow, enabledFilters, factory );
+		super( hql, collectionRole, shallow, enabledFilters, factory, null );
 		this.collectionRole = collectionRole;
 	}
 

hibernate-core/src/main/java/org/hibernate/engine/query/spi/HQLQueryPlan.java

@@ -83,8 +83,14 @@ public class HQLQueryPlan implements Serializable {
 	 * @param enabledFilters The enabled filters (we only keep the names)
 	 * @param factory The factory
 	 */
-	public HQLQueryPlan(String hql, boolean shallow, Map<String,Filter> enabledFilters, SessionFactoryImplementor factory) {
-		this( hql, null, shallow, enabledFilters, factory );
+	public HQLQueryPlan(String hql, boolean shallow, Map<String,Filter> enabledFilters,
+			SessionFactoryImplementor factory) {
+		this( hql, null, shallow, enabledFilters, factory, null );
+	}
+
+	public HQLQueryPlan(String hql, boolean shallow, Map<String,Filter> enabledFilters,
+			SessionFactoryImplementor factory, EntityGraphQueryHint entityGraphQueryHint) {
+		this( hql, null, shallow, enabledFilters, factory, entityGraphQueryHint );
 	}
 
 	@SuppressWarnings("unchecked")
@@ -93,7 +99,8 @@ protected HQLQueryPlan(
 			String collectionRole,
 			boolean shallow,
 			Map<String,Filter> enabledFilters,
-			SessionFactoryImplementor factory) {
+			SessionFactoryImplementor factory,
+			EntityGraphQueryHint entityGraphQueryHint) {
 		this.sourceQuery = hql;
 		this.shallow = shallow;
 
@@ -115,7 +122,7 @@ protected HQLQueryPlan(
 		for ( int i=0; i<length; i++ ) {
 			if ( hasCollectionRole ) {
 				translators[i] = queryTranslatorFactory
-						.createQueryTranslator( hql, concreteQueryStrings[i], enabledFilters, factory );
+						.createQueryTranslator( hql, concreteQueryStrings[i], enabledFilters, factory, entityGraphQueryHint );
 				translators[i].compile( querySubstitutions, shallow );
 			}
 			else {

hibernate-core/src/main/java/org/hibernate/engine/spi/QueryParameters.java

@@ -31,20 +31,20 @@
 import java.util.Map;
 import java.util.StringTokenizer;
 
-import org.jboss.logging.Logger;
-
 import org.hibernate.HibernateException;
 import org.hibernate.LockOptions;
 import org.hibernate.QueryException;
 import org.hibernate.ScrollMode;
 import org.hibernate.dialect.Dialect;
+import org.hibernate.engine.query.spi.HQLQueryPlan;
 import org.hibernate.hql.internal.classic.ParserHelper;
 import org.hibernate.internal.CoreMessageLogger;
 import org.hibernate.internal.FilterImpl;
 import org.hibernate.internal.util.EntityPrinter;
 import org.hibernate.internal.util.collections.ArrayHelper;
 import org.hibernate.transform.ResultTransformer;
 import org.hibernate.type.Type;
+import org.jboss.logging.Logger;
 
 /**
  * @author Gavin King
@@ -77,6 +77,8 @@ public final class QueryParameters {
 	private String processedSQL;
 	private Type[] processedPositionalParameterTypes;
 	private Object[] processedPositionalParameterValues;
+
+	private HQLQueryPlan queryPlan;
 
 	public QueryParameters() {
 		this( ArrayHelper.EMPTY_TYPE_ARRAY, ArrayHelper.EMPTY_OBJECT_ARRAY );
@@ -589,4 +591,12 @@ public QueryParameters createCopyUsing(RowSelection selection) {
 		copy.processedPositionalParameterValues = this.processedPositionalParameterValues;
 		return copy;
 	}
+
+	public HQLQueryPlan getQueryPlan() {
+		return queryPlan;
+	}
+
+	public void setQueryPlan(HQLQueryPlan queryPlan) {
+		this.queryPlan = queryPlan;
+	}
 }

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/ASTQueryTranslatorFactory.java

@@ -25,13 +25,13 @@
 package org.hibernate.hql.internal.ast;
 import java.util.Map;
 
-import org.jboss.logging.Logger;
-
+import org.hibernate.engine.query.spi.EntityGraphQueryHint;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.hql.spi.FilterTranslator;
 import org.hibernate.hql.spi.QueryTranslator;
 import org.hibernate.hql.spi.QueryTranslatorFactory;
 import org.hibernate.internal.CoreMessageLogger;
+import org.jboss.logging.Logger;
 
 /**
  * Generates translators which uses the Antlr-based parser to perform
@@ -55,8 +55,9 @@ public QueryTranslator createQueryTranslator(
 			String queryIdentifier,
 	        String queryString,
 	        Map filters,
-	        SessionFactoryImplementor factory) {
-		return new QueryTranslatorImpl( queryIdentifier, queryString, filters, factory );
+	        SessionFactoryImplementor factory,
+	        EntityGraphQueryHint entityGraphQueryHint) {
+		return new QueryTranslatorImpl( queryIdentifier, queryString, filters, factory, entityGraphQueryHint );
 	}
 
 	/**

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/HqlSqlWalker.java

@@ -180,7 +180,6 @@ public HqlSqlWalker(
 		this.printer = new ASTPrinter( SqlTokenTypes.class );
 	}
 
-
 	// handle trace logging ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 	private int traceDepth = 0;
@@ -651,6 +650,12 @@ protected void processQuery(AST select, AST query) throws SemanticException {
 
 			// Was there an explicit select expression?
 			boolean explicitSelect = select != null && select.getNumberOfChildren() > 0;
+
+			// Add in the EntityGraph attribute nodes.
+			if (queryTranslatorImpl.getEntityGraphQueryHint() != null) {
+				qn.getFromClause().getFromElements().addAll(
+						queryTranslatorImpl.getEntityGraphQueryHint().toFromElements( qn.getFromClause(), this ) );
+			}
 
 			if ( !explicitSelect ) {
 				// No explicit select expression; render the id and properties

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/QueryTranslatorImpl.java

@@ -36,6 +36,7 @@
 import org.hibernate.MappingException;
 import org.hibernate.QueryException;
 import org.hibernate.ScrollableResults;
+import org.hibernate.engine.query.spi.EntityGraphQueryHint;
 import org.hibernate.engine.spi.QueryParameters;
 import org.hibernate.engine.spi.RowSelection;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
@@ -105,6 +106,8 @@ public class QueryTranslatorImpl implements FilterTranslator {
 
 	private ParameterTranslations paramTranslations;
 	private List<ParameterSpecification> collectedParameterSpecifications;
+
+	private EntityGraphQueryHint entityGraphQueryHint;
 
 
 	/**
@@ -127,6 +130,16 @@ public QueryTranslatorImpl(
 		this.enabledFilters = enabledFilters;
 		this.factory = factory;
 	}
+
+	public QueryTranslatorImpl(
+			String queryIdentifier,
+			String query,
+			Map enabledFilters,
+			SessionFactoryImplementor factory,
+			EntityGraphQueryHint entityGraphQueryHint) {
+		this( queryIdentifier, query, enabledFilters, factory );
+		this.entityGraphQueryHint = entityGraphQueryHint;
+	}
 
 	/**
 	 * Compile a "normal" query. This method may be called multiple
@@ -612,4 +625,12 @@ private void handleDotStructure(AST dotStructureRoot) {
 			}
 		}
 	}
+
+	public EntityGraphQueryHint getEntityGraphQueryHint() {
+		return entityGraphQueryHint;
+	}
+
+	public void setEntityGraphQueryHint(EntityGraphQueryHint entityGraphQueryHint) {
+		this.entityGraphQueryHint = entityGraphQueryHint;
+	}
 }

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/DotNode.java

@@ -472,6 +472,8 @@ private void dereferenceEntityJoin(String classAlias, EntityType propertyType, b
 			if ( lhsFromElement == null ) {
 				throw new QueryException( "Unable to locate appropriate lhs" );
 			}
+
+			String role = lhsFromElement.getClassName() + "." + propertyName;
 
 			FromElementFactory factory = new FromElementFactory(
 			        currentFromClause,
@@ -487,7 +489,8 @@ private void dereferenceEntityJoin(String classAlias, EntityType propertyType, b
 					joinSequence,
 					fetch,
 					getWalker().isInFrom(),
-					propertyType
+					propertyType,
+					role
 			);
 		}
 		else {

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/FromElement.java

@@ -369,6 +369,10 @@ public boolean isCollectionJoin() {
 	public void setRole(String role) {
 		this.role = role;
 	}
+
+	public String getRole() {
+		return role;
+	}
 
 	public void setQueryableCollection(QueryableCollection queryableCollection) {
 		elementType.setQueryableCollection( queryableCollection );