HHH-13001 - NPE rendering nested criteria expressions

hibernate-core/src/main/java/org/hibernate/internal/util/collections/SingletonStack.java

@@ -0,0 +1,65 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.internal.util.collections;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+/**
+ * @author Steve Ebersole
+ */
+public class SingletonStack<T> implements Stack<T> {
+	private final T instance;
+
+	public SingletonStack(T instance) {
+		this.instance = instance;
+	}
+
+	@Override
+	public void push(T newCurrent) {
+		throw new UnsupportedOperationException( "Cannot push to a singleton Stack" );
+	}
+
+	@Override
+	public T pop() {
+		throw new UnsupportedOperationException( "Cannot pop from a singleton Stack" );
+	}
+
+	@Override
+	public T getCurrent() {
+		return instance;
+	}
+
+	@Override
+	public T getPrevious() {
+		return null;
+	}
+
+	@Override
+	public int depth() {
+		return 1;
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return false;
+	}
+
+	@Override
+	public void clear() {
+	}
+
+	@Override
+	public void visitCurrentFirst(Consumer<T> action) {
+		action.accept( instance );
+	}
+
+	@Override
+	public <X> X findCurrentFirst(Function<T, X> action) {
+		return action.apply( instance );
+	}
+}

hibernate-core/src/main/java/org/hibernate/internal/util/collections/Stack.java

@@ -0,0 +1,65 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.internal.util.collections;
+
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+/**
+ * Stack implementation exposing useful methods for Hibernate needs.
+ *
+ * @param <T> The type of things stored in the stack
+ *
+ * @author Steve Ebersole
+ */
+public interface Stack<T> {
+	/**
+	 * Push the new element on the top of the stack
+	 */
+	void push(T newCurrent);
+
+	/**
+	 * Pop (remove and return) the current element off the stack
+	 */
+	T pop();
+
+	/**
+	 * The element currently at the top of the stack
+	 */
+	T getCurrent();
+
+	/**
+	 * The element previously at the top of the stack before the current one
+	 */
+	T getPrevious();
+
+	/**
+	 * How many elements are currently on the stack?
+	 */
+	int depth();
+
+	/**
+	 * Are there no elements currently in the stack?
+	 */
+	boolean isEmpty();
+
+	/**
+	 * Remmove all elements from the stack
+	 */
+	void clear();
+
+	/**
+	 * Visit all elements in the stack, starting with the current and working back
+	 */
+	void visitCurrentFirst(Consumer<T> action);
+
+	/**
+	 * Find an element on the stack and return a value.  The first non-null element
+	 * returned from `action` stops the iteration and is returned from here
+	 */
+	<X> X findCurrentFirst(Function<T, X> action);
+}

hibernate-core/src/main/java/org/hibernate/internal/util/collections/StandardStack.java

@@ -0,0 +1,83 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.internal.util.collections;
+
+import java.util.LinkedList;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+/**
+ * A general-purpose stack impl.
+ *
+ * @param <T> The type of things stored in the stack
+ *
+ * @author Steve Ebersole
+ */
+public class StandardStack<T> implements Stack<T> {
+	private LinkedList<T> internalStack = new LinkedList<>();
+
+	public StandardStack() {
+	}
+
+	public StandardStack(T initial) {
+		internalStack.add( initial );
+	}
+
+	@Override
+	public void push(T newCurrent) {
+		internalStack.addFirst( newCurrent );
+	}
+
+	@Override
+	public T pop() {
+		return internalStack.removeFirst();
+	}
+
+	@Override
+	public T getCurrent() {
+		return internalStack.peek();
+	}
+
+	@Override
+	public T getPrevious() {
+		if ( internalStack.size() < 2 ) {
+			return null;
+		}
+		return internalStack.get( internalStack.size() - 2 );
+	}
+
+	@Override
+	public int depth() {
+		return internalStack.size();
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return internalStack.isEmpty();
+	}
+
+	@Override
+	public void clear() {
+		internalStack.clear();
+	}
+
+	@Override
+	public void visitCurrentFirst(Consumer<T> action) {
+		internalStack.forEach( action );
+	}
+
+	@Override
+	public <X> X findCurrentFirst(Function<T, X> function) {
+		for ( T t : internalStack ) {
+			final X result = function.apply( t );
+			if ( result != null ) {
+				return result;
+			}
+		}
+		return null;
+	}
+}

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/AbstractManipulationCriteriaQuery.java

@@ -25,6 +25,7 @@ import org.hibernate.query.criteria.internal.compile.InterpretedParameterMetadat
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
 import org.hibernate.query.criteria.internal.path.RootImpl;
 import org.hibernate.query.spi.QueryImplementor;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * Base class for commonality between {@link javax.persistence.criteria.CriteriaUpdate} and
@@ -155,9 +156,17 @@ public abstract class AbstractManipulationCriteriaQuery<T> implements Compilable
 	}
 
 	protected void renderRestrictions(StringBuilder jpaql, RenderingContext renderingContext) {
-		if ( getRestriction() != null) {
+		if ( getRestriction() == null ) {
+			return;
+		}
+
+		renderingContext.getClauseStack().push( Clause.WHERE );
+		try {
 			jpaql.append( " where " )
 					.append( ( (Renderable) getRestriction() ).render( renderingContext ) );
 		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
 	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/CriteriaQueryImpl.java

@@ -33,6 +33,7 @@ import org.hibernate.query.criteria.internal.compile.ImplicitParameterBinding;
 import org.hibernate.query.criteria.internal.compile.InterpretedParameterMetadata;
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
 import org.hibernate.query.spi.QueryImplementor;
+import org.hibernate.sql.ast.Clause;
 import org.hibernate.type.Type;
 
 import org.jboss.logging.Logger;
@@ -291,16 +292,7 @@ public class CriteriaQueryImpl<T> extends AbstractNode implements CriteriaQuery<
 
 		queryStructure.render( jpaqlBuffer, renderingContext );
 
-		if ( ! getOrderList().isEmpty() ) {
+		renderOrderByClause( renderingContext, jpaqlBuffer );
-			jpaqlBuffer.append( " order by " );
-			String sep = "";
-			for ( Order orderSpec : getOrderList() ) {
-				jpaqlBuffer.append( sep )
-						.append( ( ( Renderable ) orderSpec.getExpression() ).render( renderingContext ) )
-						.append( orderSpec.isAscending() ? " asc" : " desc" );
-				sep = ", ";
-			}
-		}
 
 		final String jpaqlString = jpaqlBuffer.toString();
 
@@ -385,4 +377,25 @@ public class CriteriaQueryImpl<T> extends AbstractNode implements CriteriaQuery<
 			}
 		};
 	}
+
+	protected void renderOrderByClause(RenderingContext renderingContext, StringBuilder jpaqlBuffer) {
+		if ( getOrderList().isEmpty() ) {
+			return;
+		}
+
+		renderingContext.getClauseStack().push( Clause.ORDER );
+		try {
+			jpaqlBuffer.append( " order by " );
+			String sep = "";
+			for ( Order orderSpec : getOrderList() ) {
+				jpaqlBuffer.append( sep )
+						.append( ( (Renderable) orderSpec.getExpression() ).render( renderingContext ) )
+						.append( orderSpec.isAscending() ? " asc" : " desc" );
+				sep = ", ";
+			}
+		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
+	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/CriteriaSubqueryImpl.java

@@ -27,6 +27,7 @@ import org.hibernate.query.criteria.internal.compile.RenderingContext;
 import org.hibernate.query.criteria.internal.expression.DelegatedExpressionImpl;
 import org.hibernate.query.criteria.internal.expression.ExpressionImpl;
 import org.hibernate.query.criteria.internal.path.RootImpl;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * The Hibernate implementation of the JPA {@link Subquery} contract.  Mostlty a set of delegation to its internal
@@ -257,14 +258,13 @@ public class CriteriaSubqueryImpl<T> extends ExpressionImpl<T> implements Subque
 
 	@Override
 	public String render(RenderingContext renderingContext) {
+		if ( renderingContext.getClauseStack().getCurrent() == Clause.SELECT ) {
+			throw new IllegalStateException( "Subquery cannot occur in select clause" );
+		}
+
 		StringBuilder subqueryBuffer = new StringBuilder( "(" );
 		queryStructure.render( subqueryBuffer, renderingContext );
 		subqueryBuffer.append( ')' );
 		return subqueryBuffer.toString();
 	}
-
-	@Override
-	public String renderProjection(RenderingContext renderingContext) {
-		throw new IllegalStateException( "Subquery cannot occur in select clause" );
-	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/CriteriaUpdateImpl.java

@@ -16,6 +16,7 @@ import javax.persistence.metamodel.SingularAttribute;
 
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
 import org.hibernate.query.criteria.internal.path.SingularAttributePath;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * Hibernate implementation of the JPA 2.1 {@link CriteriaUpdate} contract.
@@ -122,6 +123,9 @@ public class CriteriaUpdateImpl<T> extends AbstractManipulationCriteriaQuery<T>
 	}
 
 	private void renderAssignments(StringBuilder jpaql, RenderingContext renderingContext) {
+		renderingContext.getClauseStack().push( Clause.UPDATE );
+
+		try {
 			jpaql.append( " set " );
 			boolean first = true;
 			for ( Assignment assignment : assignments ) {
@@ -134,6 +138,10 @@ public class CriteriaUpdateImpl<T> extends AbstractManipulationCriteriaQuery<T>
 				first = false;
 			}
 		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
+	}
 
 	private static class Assignment<A> {
 		private final SingularAttributePath<A> attributePath;

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/QueryStructure.java

@@ -31,6 +31,7 @@ import javax.persistence.metamodel.EntityType;
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
 import org.hibernate.query.criteria.internal.path.RootImpl;
 import org.hibernate.query.criteria.internal.path.RootImpl.TreatedRoot;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * Models basic query structure.  Used as a delegate in implementing both
@@ -230,37 +231,34 @@ public class QueryStructure<T> implements Serializable {
 
 	@SuppressWarnings({ "unchecked" })
 	public void render(StringBuilder jpaqlQuery, RenderingContext renderingContext) {
-		jpaqlQuery.append( "select " );
+		renderSelectClause( jpaqlQuery, renderingContext );
-		if ( isDistinct() ) {
-			jpaqlQuery.append( "distinct " );
-		}
-		if ( getSelection() == null ) {
-			jpaqlQuery.append( locateImplicitSelection().renderProjection( renderingContext ) );
-		}
-		else {
-			jpaqlQuery.append( ( (Renderable) getSelection() ).renderProjection( renderingContext ) );
-		}
 
 		renderFromClause( jpaqlQuery, renderingContext );
 
-		if ( getRestriction() != null) {
+		renderWhereClause( jpaqlQuery, renderingContext );
-			jpaqlQuery.append( " where " )
+
-					.append( ( (Renderable) getRestriction() ).render( renderingContext ) );
+		renderGroupByClause( jpaqlQuery, renderingContext );
 	}
 
-		if ( ! getGroupings().isEmpty() ) {
+	protected void renderSelectClause(StringBuilder jpaqlQuery, RenderingContext renderingContext) {
-			jpaqlQuery.append( " group by " );
+		renderingContext.getClauseStack().push( Clause.SELECT );
-			String sep = "";
+
-			for ( Expression grouping : getGroupings() ) {
+		try {
-				jpaqlQuery.append( sep )
+			jpaqlQuery.append( "select " );
-						.append( ( (Renderable) grouping ).renderGroupBy( renderingContext ) );
+
-				sep = ", ";
+			if ( isDistinct() ) {
+				jpaqlQuery.append( "distinct " );
 			}
 
-			if ( getHaving() != null ) {
+			if ( getSelection() == null ) {
-				jpaqlQuery.append( " having " )
+				jpaqlQuery.append( locateImplicitSelection().render( renderingContext ) );
-						.append( ( (Renderable) getHaving() ).render( renderingContext ) );
 			}
+			else {
+				jpaqlQuery.append( ( (Renderable) getSelection() ).render( renderingContext ) );
+			}
+		}
+		finally {
+			renderingContext.getClauseStack().pop();
 		}
 	}
 
@@ -290,13 +288,16 @@ public class QueryStructure<T> implements Serializable {
 
 	@SuppressWarnings({ "unchecked" })
 	private void renderFromClause(StringBuilder jpaqlQuery, RenderingContext renderingContext) {
+		renderingContext.getClauseStack().push( Clause.FROM );
+
+		try {
 			jpaqlQuery.append( " from " );
 			String sep = "";
 			for ( Root root : getRoots() ) {
 				( (FromImplementor) root ).prepareAlias( renderingContext );
 				jpaqlQuery.append( sep );
-			jpaqlQuery.append( ( (FromImplementor) root ).renderTableExpression( renderingContext ) );
 				sep = ", ";
+				jpaqlQuery.append( ( (FromImplementor) root ).renderTableExpression( renderingContext ) );
 			}
 
 			for ( Root root : getRoots() ) {
@@ -333,6 +334,61 @@ public class QueryStructure<T> implements Serializable {
 				}
 			}
 		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
+	}
+
+	protected void renderWhereClause(StringBuilder jpaqlQuery, RenderingContext renderingContext) {
+		if ( getRestriction() == null ) {
+			return;
+		}
+
+		renderingContext.getClauseStack().push( Clause.WHERE );
+		try {
+			jpaqlQuery.append( " where " )
+					.append( ( (Renderable) getRestriction() ).render( renderingContext ) );
+		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
+	}
+
+	protected void renderGroupByClause(StringBuilder jpaqlQuery, RenderingContext renderingContext) {
+		if ( getGroupings().isEmpty() ) {
+			return;
+		}
+
+		renderingContext.getClauseStack().push( Clause.GROUP );
+		try {
+			jpaqlQuery.append( " group by " );
+			String sep = "";
+			for ( Expression grouping : getGroupings() ) {
+				jpaqlQuery.append( sep )
+						.append( ( (Renderable) grouping ).render( renderingContext ) );
+				sep = ", ";
+			}
+
+			renderHavingClause( jpaqlQuery, renderingContext );
+		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
+	}
+
+	private void renderHavingClause(StringBuilder jpaqlQuery, RenderingContext renderingContext) {
+		if ( getHaving() == null ) {
+			return;
+		}
+
+		renderingContext.getClauseStack().push( Clause.HAVING );
+		try {
+			jpaqlQuery.append( " having " ).append( ( (Renderable) getHaving() ).render( renderingContext ) );
+		}
+		finally {
+			renderingContext.getClauseStack().pop();
+		}
+	}
 
 	@SuppressWarnings({ "unchecked" })
 	private void renderJoins(

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/Renderable.java

@@ -10,38 +10,15 @@ package org.hibernate.query.criteria.internal;
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
 
 /**
- * TODO : javadoc
+ * Contract for nodes in the JPA Criteria tree that can be rendered
+ * as part of criteria "compilation"
  *
  * @author Steve Ebersole
  */
 public interface Renderable {
 
 	/**
-	 * Render clause
+	 * Perform the rendering, returning the rendition
-	 *
-	 * @param renderingContext context
-	 * @return rendered expression
 	 */
 	String render(RenderingContext renderingContext);
-
-	/**
-	 * Render SELECT clause
-	 *
-	 * @param renderingContext context
-	 * @return rendered expression
-	 */
-	default String renderProjection(RenderingContext renderingContext) {
-		return render( renderingContext );
-	}
-
-	/**
-	 * Render GROUP BY clause
-	 *
-	 * @param renderingContext context
-	 *
-	 * @return rendered expression
-	 */
-	default String renderGroupBy(RenderingContext renderingContext) {
-		return render( renderingContext );
-	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/compile/CriteriaCompiler.java

@@ -20,8 +20,12 @@ import org.hibernate.engine.jdbc.spi.JdbcServices;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.engine.spi.SessionImplementor;
 import org.hibernate.internal.util.StringHelper;
+import org.hibernate.internal.util.collections.Stack;
+import org.hibernate.internal.util.collections.StandardStack;
 import org.hibernate.query.criteria.LiteralHandlingMode;
+import org.hibernate.query.criteria.internal.expression.function.FunctionExpression;
 import org.hibernate.query.spi.QueryImplementor;
+import org.hibernate.sql.ast.Clause;
 import org.hibernate.type.Type;
 
 /**
@@ -63,6 +67,9 @@ public class CriteriaCompiler implements Serializable {
 			private int aliasCount;
 			private int explicitParameterCount;
 
+			private final Stack<Clause> clauseStack = new StandardStack<>();
+			private final Stack<FunctionExpression> functionContextStack = new StandardStack<>();
+
 			public String generateAlias() {
 				return "generatedAlias" + aliasCount++;
 			}
@@ -71,6 +78,16 @@ public class CriteriaCompiler implements Serializable {
 				return "param" + explicitParameterCount++;
 			}
 
+			@Override
+			public Stack<Clause> getClauseStack() {
+				return clauseStack;
+			}
+
+			@Override
+			public Stack<FunctionExpression> getFunctionStack() {
+				return functionContextStack;
+			}
+
 			@Override
 			@SuppressWarnings("unchecked")
 			public ExplicitParameterInfo registerExplicitParameter(ParameterExpression<?> criteriaQueryParameter) {

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/compile/RenderingContext.java

@@ -9,7 +9,10 @@ package org.hibernate.query.criteria.internal.compile;
 import javax.persistence.criteria.ParameterExpression;
 
 import org.hibernate.dialect.Dialect;
+import org.hibernate.internal.util.collections.Stack;
 import org.hibernate.query.criteria.LiteralHandlingMode;
+import org.hibernate.query.criteria.internal.expression.function.FunctionExpression;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * Used to provide a context and services to the rendering.
@@ -67,4 +70,8 @@ public interface RenderingContext {
 	default LiteralHandlingMode getCriteriaLiteralHandlingMode() {
 		return LiteralHandlingMode.AUTO;
 	}
+
+	Stack<Clause> getClauseStack();
+
+	Stack<FunctionExpression> getFunctionStack();
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/CompoundSelectionImpl.java

@@ -77,15 +77,17 @@ public class CompoundSelectionImpl<X>
 		if ( isConstructor ) {
 			buff.append( "new " ).append( getJavaType().getName() ).append( '(' );
 		}
+
 		String sep = "";
 		for ( Selection selection : selectionItems ) {
-			buff.append( sep )
+			buff.append( sep ).append( ( (Renderable) selection ).render( renderingContext ) );
-					.append( ( (Renderable) selection ).renderProjection( renderingContext ) );
 			sep = ", ";
 		}
+
 		if ( isConstructor ) {
 			buff.append( ')' );
 		}
+
 		return buff.toString();
 	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/LiteralExpression.java

@@ -47,37 +47,54 @@ public class LiteralExpression<T> extends ExpressionImpl<T> implements Serializa
 
 	@SuppressWarnings({ "unchecked" })
 	public String render(RenderingContext renderingContext) {
+		switch ( renderingContext.getClauseStack().getCurrent() ) {
+			case SELECT: {
+				return renderProjection();
+			}
+			case GROUP: {
+				// technically a literal in the group-by clause
+				// would be a reference to the position of a selection
+				//
+				// but this is what the code used to do...
+				return renderProjection();
+			}
+			default: {
+				return normalRender( renderingContext );
+			}
+		}
+	}
 
+	@SuppressWarnings("unchecked")
+	private String normalRender(RenderingContext renderingContext) {
 		LiteralHandlingMode literalHandlingMode = renderingContext.getCriteriaLiteralHandlingMode();
 
 		switch ( literalHandlingMode ) {
-			case AUTO:
+			case AUTO: {
 				if ( ValueHandlerFactory.isNumeric( literal ) ) {
 					return ValueHandlerFactory.determineAppropriateHandler( (Class) literal.getClass() ).render( literal );
 				}
 				else {
 					return bindLiteral( renderingContext );
 				}
-			case BIND:
+			}
+			case BIND: {
 				return bindLiteral( renderingContext );
-			case INLINE:
+			}
+			case INLINE: {
 				Object literalValue = literal;
 				if ( String.class.equals( literal.getClass() ) ) {
 					literalValue = renderingContext.getDialect().inlineLiteral( (String) literal );
 				}
+
 				return ValueHandlerFactory.determineAppropriateHandler( (Class) literal.getClass() ).render( literalValue );
-			default:
+			}
+			default: {
 				throw new IllegalArgumentException( "Unexpected LiteralHandlingMode: " + literalHandlingMode );
 			}
 		}
-
-	private String bindLiteral(RenderingContext renderingContext) {
-		final String parameterName = renderingContext.registerLiteralParameterBinding( getLiteral(), getJavaType() );
-		return ':' + parameterName;
 	}
 
-	@SuppressWarnings({ "unchecked" })
+	private String renderProjection() {
-	public String renderProjection(RenderingContext renderingContext) {
 		// some drivers/servers do not like parameters in the select clause
 		final ValueHandlerFactory.ValueHandler handler =
 				ValueHandlerFactory.determineAppropriateHandler( literal.getClass() );
@@ -89,9 +106,9 @@ public class LiteralExpression<T> extends ExpressionImpl<T> implements Serializa
 		}
 	}
 
-	@Override
+	private String bindLiteral(RenderingContext renderingContext) {
-	public String renderGroupBy(RenderingContext renderingContext) {
+		final String parameterName = renderingContext.registerLiteralParameterBinding( getLiteral(), getJavaType() );
-		return renderProjection( renderingContext );
+		return ':' + parameterName;
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/MapEntryExpression.java

@@ -16,6 +16,7 @@ import org.hibernate.query.criteria.internal.ParameterRegistry;
 import org.hibernate.query.criteria.internal.PathImplementor;
 import org.hibernate.query.criteria.internal.Renderable;
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * TODO : javadoc
@@ -48,17 +49,17 @@ public class MapEntryExpression<K,V>
 	}
 
 	public String render(RenderingContext renderingContext) {
-		// don't think this is valid outside of select clause...
+		if ( renderingContext.getClauseStack().getCurrent() == Clause.SELECT ) {
-		throw new IllegalStateException( "illegal reference to map entry outside of select clause." );
+			return "entry(" + path( renderingContext ) + ")";
 		}
 
-	public String renderProjection(RenderingContext renderingContext) {
+		// don't think this is valid outside of select clause...
-		return "entry(" + path( renderingContext ) + ")";
+		throw new IllegalStateException( "illegal reference to map entry outside of select clause." );
 	}
 
 	private String path(RenderingContext renderingContext) {
 		return origin.getPathIdentifier()
 				+ '.'
-				+ ( (Renderable) getAttribute() ).renderProjection( renderingContext );
+				+ ( (Renderable) getAttribute() ).render( renderingContext );
 	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/NullLiteralExpression.java

@@ -12,6 +12,7 @@ import org.hibernate.query.criteria.internal.CriteriaBuilderImpl;
 import org.hibernate.query.criteria.internal.ParameterRegistry;
 import org.hibernate.query.criteria.internal.compile.RenderingContext;
 import org.hibernate.query.criteria.internal.expression.function.CastFunction;
+import org.hibernate.sql.ast.Clause;
 
 /**
  * Represents a <tt>NULL</tt>literal expression.
@@ -28,10 +29,13 @@ public class NullLiteralExpression<T> extends ExpressionImpl<T> implements Seria
 	}
 
 	public String render(RenderingContext renderingContext) {
-		return "null";
+		if ( renderingContext.getClauseStack().getCurrent() == Clause.SELECT ) {
-	}
+			// in the select clause render the ``null` using a cast so the db analyzer/optimizer
-
+			// understands the type
-	public String renderProjection(RenderingContext renderingContext) {
 			return CastFunction.CAST_NAME + "( 	null  as " + renderingContext.getCastType( getJavaType() ) + ')';
 		}
+
+		// otherwise, just render `null`
+		return "null";
+	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SearchedCaseExpression.java

@@ -106,41 +106,18 @@ public class SearchedCaseExpression<R>
 	}
 
 	public String render(RenderingContext renderingContext) {
-		return render(
-				renderingContext,
-				(Renderable expression, RenderingContext context) -> expression.render( context )
-		);
-	}
-
-	public String renderProjection(RenderingContext renderingContext) {
-		return render(
-				renderingContext,
-				(Renderable expression, RenderingContext context) -> expression.renderProjection( context )
-		);
-	}
-
-	@Override
-	public String renderGroupBy(RenderingContext renderingContext) {
-		return render(
-				renderingContext,
-				(Renderable expression, RenderingContext context) -> expression.renderGroupBy( context )
-		);
-	}
-
-	private String render(
-			RenderingContext renderingContext,
-			BiFunction<Renderable, RenderingContext, String> formatter) {
 		StringBuilder caseStatement = new StringBuilder( "case" );
 		for ( WhenClause whenClause : getWhenClauses() ) {
 			caseStatement.append( " when " )
-					.append( formatter.apply( (Renderable) whenClause.getCondition(), renderingContext ) )
+					.append( ( (Renderable) whenClause.getCondition() ).render( renderingContext ) )
 					.append( " then " )
-					.append( formatter.apply( ((Renderable) whenClause.getResult()), renderingContext ) );
+					.append( ( (Renderable) whenClause.getResult() ).render( renderingContext ) );
-		}
-		caseStatement.append( " else " )
-				.append( formatter.apply( (Renderable) getOtherwiseResult(), renderingContext ) )
-				.append( " end" );
-		return caseStatement.toString();
 		}
 
+		caseStatement.append( " else " )
+				.append( ( (Renderable) getOtherwiseResult() ).render( renderingContext ) )
+				.append( " end" );
+
+		return caseStatement.toString();
+	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/SimpleCaseExpression.java

@@ -9,7 +9,6 @@ package org.hibernate.query.criteria.internal.expression;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.function.BiFunction;
 import javax.persistence.criteria.CriteriaBuilder.SimpleCase;
 import javax.persistence.criteria.Expression;
 
@@ -118,44 +117,21 @@ public class SimpleCaseExpression<C,R>
 
 	@Override
 	public String render(RenderingContext renderingContext) {
-		return render(
-				renderingContext,
-				(Renderable expression, RenderingContext context) -> expression.render( context )
-		);
-	}
-
-	@Override
-	public String renderProjection(RenderingContext renderingContext) {
-		return render(
-				renderingContext,
-				(Renderable expression, RenderingContext context) -> expression.renderProjection( context )
-		);
-	}
-
-	@Override
-	public String renderGroupBy(RenderingContext renderingContext) {
-		return render(
-				renderingContext,
-				(Renderable expression, RenderingContext context) -> expression.renderGroupBy( context )
-		);
-	}
-
-	private String render(
-			RenderingContext renderingContext,
-			BiFunction<Renderable, RenderingContext, String> formatter) {
 		StringBuilder caseExpr = new StringBuilder();
 		caseExpr.append( "case " )
-				.append( formatter.apply( (Renderable) getExpression(), renderingContext ) );
+				.append( ( (Renderable) getExpression() ).render( renderingContext ) );
+
 		for ( WhenClause whenClause : getWhenClauses() ) {
 			caseExpr.append( " when " )
-					.append( formatter.apply( whenClause.getCondition(), renderingContext ) )
+					.append( whenClause.getCondition().render( renderingContext ) )
 					.append( " then " )
-					.append( formatter.apply( (Renderable) whenClause.getResult(), renderingContext ) );
+					.append( ( (Renderable) whenClause.getResult() ).render( renderingContext ) );
-		}
-		caseExpr.append( " else " )
-				.append( formatter.apply( (Renderable) getOtherwiseResult(), renderingContext ) )
-				.append( " end" );
-		return caseExpr.toString();
 		}
 
+		caseExpr.append( " else " )
+				.append( ( (Renderable) getOtherwiseResult() ).render( renderingContext ) )
+				.append( " end" );
+
+		return caseExpr.toString();
+	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/function/CastFunction.java

@@ -7,6 +7,7 @@
 package org.hibernate.query.criteria.internal.expression.function;
 
 import java.io.Serializable;
+import java.util.Locale;
 
 import org.hibernate.query.criteria.internal.CriteriaBuilderImpl;
 import org.hibernate.query.criteria.internal.ParameterRegistry;
@@ -47,10 +48,17 @@ public class CastFunction<T,Y>
 
 	@Override
 	public String render(RenderingContext renderingContext) {
-		return CAST_NAME + '(' +
+		renderingContext.getFunctionStack().push( this );
-				castSource.render( renderingContext ) +
+		try {
-				" as " +
+			return String.format(
-				renderingContext.getCastType( getJavaType() ) +
+					Locale.ROOT,
-				')';
+					"cast(%s as %s)",
+					castSource.render( renderingContext ),
+					renderingContext.getCastType( getJavaType() )
+			);
+		}
+		finally {
+			renderingContext.getFunctionStack().pop();
+		}
 	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/function/LocateFunction.java

@@ -86,16 +86,26 @@ public class LocateFunction
 
 	@Override
 	public String render(RenderingContext renderingContext) {
-		StringBuilder buffer = new StringBuilder();
+		renderingContext.getFunctionStack().push( this );
+
+		try {
+			final StringBuilder buffer = new StringBuilder();
 			buffer.append( "locate(" )
 					.append( ( (Renderable) getPattern() ).render( renderingContext ) )
 					.append( ',' )
 					.append( ( (Renderable) getString() ).render( renderingContext ) );
+
 			if ( getStart() != null ) {
 				buffer.append( ',' )
 						.append( ( (Renderable) getStart() ).render( renderingContext ) );
 			}
+
 			buffer.append( ')' );
+
 			return buffer.toString();
 		}
+		finally {
+			renderingContext.getFunctionStack().pop();
+		}
+	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/function/ParameterizedFunctionExpression.java

@@ -93,19 +93,26 @@ public class ParameterizedFunctionExpression<X>
 
 	@Override
 	public String render(RenderingContext renderingContext) {
-		StringBuilder buffer = new StringBuilder();
+		renderingContext.getFunctionStack().push( this );
+
+		try {
+			final StringBuilder buffer = new StringBuilder();
 			if ( isStandardJpaFunction() ) {
-			buffer.append( getFunctionName() )
+				buffer.append( getFunctionName() ).append( "(" );
-					.append( "(" );
 			}
 			else {
 				buffer.append( "function('" )
 						.append( getFunctionName() )
 						.append( "', " );
 			}
+
 			renderArguments( buffer, renderingContext );
-		buffer.append( ')' );
+
-		return buffer.toString();
+			return buffer.append( ')' ).toString();
+		}
+		finally {
+			renderingContext.getFunctionStack().pop();
+		}
 	}
 
 	protected void renderArguments(StringBuilder buffer, RenderingContext renderingContext) {

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/function/SubstringFunction.java

@@ -92,16 +92,24 @@ public class SubstringFunction
 	}
 
 	public String render(RenderingContext renderingContext) {
-		StringBuilder buffer = new StringBuilder();
+		renderingContext.getFunctionStack().push( this );
+
+		try {
+			final StringBuilder buffer = new StringBuilder();
 			buffer.append( "substring(" )
 					.append( ( (Renderable) getValue() ).render( renderingContext ) )
 					.append( ',' )
 					.append( ( (Renderable) getStart() ).render( renderingContext ) );
+
 			if ( getLength() != null ) {
 				buffer.append( ',' )
 						.append( ( (Renderable) getLength() ).render( renderingContext ) );
 			}
-		buffer.append( ')' );
+
-		return buffer.toString();
+			return buffer.append( ')' ).toString();
+		}
+		finally {
+			renderingContext.getFunctionStack().pop();
+		}
 	}
 }

hibernate-core/src/main/java/org/hibernate/query/criteria/internal/expression/function/TrimFunction.java

@@ -102,17 +102,18 @@ public class TrimFunction
 
 	@Override
 	public String render(RenderingContext renderingContext) {
+		renderingContext.getFunctionStack().push( this );
+
+		try {
 			String renderedTrimChar;
-		if ( trimCharacter.getClass().isAssignableFrom( 
+			if ( trimCharacter.getClass().isAssignableFrom( LiteralExpression.class ) ) {
-				LiteralExpression.class ) ) {
 				// If the character is a literal, treat it as one.  A few dialects
 				// do not support parameters as trim() arguments.
 				renderedTrimChar = '\'' + ( (LiteralExpression<Character>)
 						trimCharacter ).getLiteral().toString() + '\'';
 			}
 			else {
-			renderedTrimChar = ( (Renderable) trimCharacter ).render( 
+				renderedTrimChar = ( (Renderable) trimCharacter ).render( renderingContext );
-					renderingContext );
 			}
 			return new StringBuilder()
 					.append( "trim(" )
@@ -124,4 +125,8 @@ public class TrimFunction
 					.append( ')' )
 					.toString();
 		}
+		finally {
+			renderingContext.getFunctionStack().pop();
+		}
+	}
 }

hibernate-core/src/main/java/org/hibernate/sql/ast/Clause.java

@@ -0,0 +1,49 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.sql.ast;
+
+import org.hibernate.Incubating;
+
+/**
+ * Used to indicate which query clause we are currently processing
+ *
+ * @author Steve Ebersole
+ */
+@Incubating
+public enum Clause {
+	/**
+	 * The insert values clause
+	 */
+	INSERT,
+
+	/**
+	 * The update set clause
+	 */
+	UPDATE,
+
+	/**
+	 * Not used in 5.x.  Intended for use in 6+ as indicator
+	 * of processing predicates (where clause) that occur in a
+	 * delete
+	 */
+	DELETE,
+
+	SELECT,
+	FROM,
+	WHERE,
+	GROUP,
+	HAVING,
+	ORDER,
+	LIMIT,
+	CALL,
+
+	/**
+	 * Again, not used in 5.x.  Used in 6+
+	 */
+	IRRELEVANT
+
+}