DATACMNS-1177 - Parameter.isDynamicProjectionParameter() now uses unwrapped type instead of actual type.

When trying to determine if a parameter is a dynamic projection parameter, i.e. the parameter of type Class that determines the projection to use, now the type parameter of that method parameter gets compared with the unwrapped return type. Therefore this works now not only for Maps and Collections but also for the various wrappers defined in QueryExecutionConverters.

Moved the method for unwrapping the return type from AbstractRepositoryMetadata to QueryExecutionConverters in order to make it available to every class needing it. This also puts it closer to the data it is working on.

Original pull request: #250.

src/test/java/org/springframework/data/repository/query/ParameterUnitTests.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.repository.query;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Stream;
+
+import org.jetbrains.annotations.NotNull;
+import org.junit.Test;
+import org.springframework.core.MethodParameter;
+
+/**
+ * Unit tests for {@link Parameter}.
+ *
+ * @author Jens Schauder
+ */
+public class ParameterUnitTests {
+
+	@Test // DATAJPA-1185
+	public void classParameterWithSameTypeParameterAsReturnedListIsDynamicProjectionParameter() throws Exception {
+
+		Parameter parameter = new Parameter(getMethodParameter("dynamicProjectionWithList"));
+
+		assertThat(parameter.isDynamicProjectionParameter()).isTrue();
+	}
+
+	@Test // DATAJPA-1185
+	public void classParameterWithSameTypeParameterAsReturnedStreamIsDynamicProjectionParameter() throws Exception {
+
+		Parameter parameter = new Parameter(getMethodParameter("dynamicProjectionWithStream"));
+
+		assertThat(parameter.isDynamicProjectionParameter()).isTrue();
+	}
+
+	@NotNull
+	private MethodParameter getMethodParameter(String methodName) throws NoSuchMethodException {
+		return new MethodParameter( //
+				this.getClass().getDeclaredMethod( //
+						methodName, //
+						Class.class //
+				), //
+				0);
+	}
+
+	<T> List<T> dynamicProjectionWithList(Class<T> type) {
+		return Collections.emptyList();
+	}
+
+	<T> Stream<T> dynamicProjectionWithStream(Class<T> type) {
+		return Stream.empty();
+	}
+}