From 6cc838a3f8d5933725be0c646b84bb2a9a9e0901 Mon Sep 17 00:00:00 2001
From: Oliver Wehrens <oliver@wehrens.de>
Date: Sun, 13 Apr 2014 15:20:00 +0200
Subject: [PATCH] DATAJPA-513 - Improve error message on missing @Param on
 query method parameter.

StringQuery now hints to the usage of @Param on query method parameters if named parameters are used and parameter names were not declared.

Original pull request: #77.
---
 .../jpa/repository/query/StringQuery.java     |  5 ++++-
 .../query/StringQueryUnitTests.java           | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/springframework/data/jpa/repository/query/StringQuery.java b/src/main/java/org/springframework/data/jpa/repository/query/StringQuery.java
index f26eeedaa..eef1ce951 100644
--- a/src/main/java/org/springframework/data/jpa/repository/query/StringQuery.java
+++ b/src/main/java/org/springframework/data/jpa/repository/query/StringQuery.java
@@ -36,9 +36,12 @@ import org.springframework.util.StringUtils;
  * 
  * @author Oliver Gierke
  * @author Thomas Darimont
+ * @author Oliver Wehrens
  */
 class StringQuery {
 
+	private static final String PARAMETER_NAME_MISSING = "Name for parameter binding must not be null or empty! For named parameters you need to use @Param for query method parameters on Java versions < 8.";
+
 	private final String query;
 	private final List<ParameterBinding> bindings;
 	private final String alias;
@@ -102,7 +105,7 @@ class StringQuery {
 	 */
 	public ParameterBinding getBindingFor(String name) {
 
-		Assert.hasText(name, "Name must not be null or empty!");
+		Assert.hasText(name, PARAMETER_NAME_MISSING);
 
 		for (ParameterBinding binding : bindings) {
 			if (binding.hasName(name)) {
diff --git a/src/test/java/org/springframework/data/jpa/repository/query/StringQueryUnitTests.java b/src/test/java/org/springframework/data/jpa/repository/query/StringQueryUnitTests.java
index 4cf2f5931..6db2514a4 100644
--- a/src/test/java/org/springframework/data/jpa/repository/query/StringQueryUnitTests.java
+++ b/src/test/java/org/springframework/data/jpa/repository/query/StringQueryUnitTests.java
@@ -20,10 +20,13 @@ import static org.junit.Assert.*;
 
 import java.util.List;
 
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.springframework.data.jpa.repository.query.StringQuery.InParameterBinding;
 import org.springframework.data.jpa.repository.query.StringQuery.LikeParameterBinding;
 import org.springframework.data.jpa.repository.query.StringQuery.ParameterBinding;
+import org.springframework.data.repository.query.Param;
 import org.springframework.data.repository.query.parser.Part.Type;
 
 /**
@@ -34,6 +37,8 @@ import org.springframework.data.repository.query.parser.Part.Type;
  */
 public class StringQueryUnitTests {
 
+	public @Rule ExpectedException exception = ExpectedException.none();
+
 	/**
 	 * @see DATAJPA-341
 	 */
@@ -227,6 +232,20 @@ public class StringQueryUnitTests {
 		assertNamedBinding(InParameterBinding.class, "statuses", bindings.get(0));
 	}
 
+	/**
+	 * @see DATAJPA-513
+	 */
+	@Test
+	public void rejectsNullParameterNameHintingTowardsAtParamForNullParameterName() {
+
+		StringQuery query = new StringQuery("select x from X");
+
+		exception.expect(IllegalArgumentException.class);
+		exception.expectMessage(Param.class.getSimpleName());
+
+		query.getBindingFor(null);
+	}
+
 	private void assertPositionalBinding(Class<? extends ParameterBinding> bindingType, Integer position,
 			ParameterBinding expectedBinding) {