DATAJPA-629 - Allow SpEL template expressions in combination with parameter expressions in @Query.

Previously SpEL template expressions like #{#entityName} could not be used in conjunction with parameter expressions in @Query because the SpEL template parser tried to evaluate the dynamic parameter expressions as well. We now mask the parameters prior to evaluating the SpEL template expression.

Original pull request: #122.

src/main/java/org/springframework/data/jpa/repository/query/ExpressionBasedStringQuery.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 the original author or authors.
+ * Copyright 2013-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
  */
 package org.springframework.data.jpa.repository.query;
 
+import java.util.regex.Pattern;
+
 import org.springframework.data.repository.core.EntityMetadata;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ParserContext;
@@ -35,6 +37,13 @@ import org.springframework.util.Assert;
  */
 class ExpressionBasedStringQuery extends StringQuery {
 
+	private static final String EXPRESSION_PARAMETER = "?#{";
+	private static final String QUOTED_EXPRESSION_PARAMETER = "?__HASH__{";
+
+	private static final Pattern EXPRESSION_PARAMETER_QUOTING = Pattern.compile(Pattern.quote(EXPRESSION_PARAMETER));
+	private static final Pattern EXPRESSION_PARAMETER_UNQUOTING = Pattern.compile(Pattern
+			.quote(QUOTED_EXPRESSION_PARAMETER));
+
 	private static final String ENTITY_NAME = "entityName";
 	private static final String ENTITY_NAME_VARIABLE = "#" + ENTITY_NAME;
 	private static final String ENTITY_NAME_VARIABLE_EXPRESSION = "#{" + ENTITY_NAME_VARIABLE + "}";
@@ -70,10 +79,25 @@ class ExpressionBasedStringQuery extends StringQuery {
 		StandardEvaluationContext evalContext = new StandardEvaluationContext();
 		evalContext.setVariable(ENTITY_NAME, metadata.getEntityName());
 
+		query = potentiallyQuoteExpressionsParameter(query);
+
 		Expression expr = parser.parseExpression(query, ParserContext.TEMPLATE_EXPRESSION);
 
-		Object result = expr.getValue(evalContext, String.class);
-		return result == null ? query : String.valueOf(result);
+		String result = expr.getValue(evalContext, String.class);
+
+		if (result == null) {
+			return query;
+		}
+
+		return potentiallyUnquoteParameterExpressions(result);
+	}
+
+	private static String potentiallyUnquoteParameterExpressions(String result) {
+		return EXPRESSION_PARAMETER_UNQUOTING.matcher(result).replaceAll(EXPRESSION_PARAMETER);
+	}
+
+	private static String potentiallyQuoteExpressionsParameter(String query) {
+		return EXPRESSION_PARAMETER_QUOTING.matcher(query).replaceAll(QUOTED_EXPRESSION_PARAMETER);
 	}
 
 	private static boolean containsExpression(String query) {

src/test/java/org/springframework/data/jpa/repository/UserRepositoryTests.java

@@ -1753,6 +1753,20 @@ public class UserRepositoryTests {
 		assertThat(users.getContent().get(1), is(fourthUser));
 	}
 
+	/**
+	 * @see DATAJPA-629
+	 */
+	@Test
+	public void shouldfindUsersBySpELExpressionParametersWithSpelTemplateExpression() {
+
+		flushTestUsers();
+		List<User> users = repository.findUsersByFirstnameForSpELExpressionWithParameterIndexOnlyWithEntityExpression(
+				"Joachim", "Arrasz");
+
+		assertThat(users, hasSize(1));
+		assertThat(users.get(0), is(secondUser));
+	}
+
 	private Page<User> executeSpecWithSort(Sort sort) {
 
 		flushTestUsers();

src/test/java/org/springframework/data/jpa/repository/sample/UserRepository.java

@@ -459,7 +459,7 @@ public interface UserRepository extends JpaRepository<User, Integer>, JpaSpecifi
 	 */
 	@Query("select u from User u where u.emailAddress = ?1")
 	Optional<User> findOptionalByEmailAddress(String emailAddress);
-	
+
 	/**
 	 * @see DATAJPA-564
 	 */
@@ -527,4 +527,11 @@ public interface UserRepository extends JpaRepository<User, Integer>, JpaSpecifi
 			value = "select * from (select rownum() as RN, u.* from User u) where RN between ?#{ #pageable.offset -1} and ?#{#pageable.offset + #pageable.pageSize}",
 			countQuery = "select count(u.id) from User u", nativeQuery = true)
 	Page<User> findUsersInNativeQueryWithPagination(Pageable pageable);
+
+	/**
+	 * @see DATAJPA-629
+	 */
+	@Query("select u from #{#entityName} u where u.firstname = ?#{[0]} and u.lastname = ?#{[1]}")
+	List<User> findUsersByFirstnameForSpELExpressionWithParameterIndexOnlyWithEntityExpression(String firstname,
+			String lastname);
 }