DATACMNS-364 - Infrastructure to allow redeclaring CRUD methods with queries.

Introduced new meta-annotation QueryAnnotation to mark and identify store specific Query annotations. This enables us to handle finder methods annotated with such store specific annotations in a generic way. Adjusted DefaultRepositoryInformation.getQueryMethods(…) to consider custom store specific query annotations.

Original pull request: #43.

src/main/java/org/springframework/data/annotation/QueryAnnotation.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2013 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.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.data.repository.Repository;
+
+/**
+ * Meta-Annotation to mark a store specific annotation as a query annotation. This allows generic special handing of
+ * finder methods on {@link Repository} interfaces.
+ * 
+ * @author Thomas Darimont
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.ANNOTATION_TYPE)
+public @interface QueryAnnotation {
+}

src/main/java/org/springframework/data/repository/core/support/DefaultRepositoryInformation.java

@@ -29,6 +29,8 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 import org.springframework.core.MethodParameter;
+import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.data.annotation.QueryAnnotation;
 import org.springframework.data.repository.Repository;
 import org.springframework.data.repository.core.CrudMethods;
 import org.springframework.data.repository.core.RepositoryInformation;
@@ -167,7 +169,7 @@ class DefaultRepositoryInformation extends AbstractRepositoryMetadata implements
 
 		for (Method method : getRepositoryInterface().getMethods()) {
 			method = ClassUtils.getMostSpecificMethod(method, getRepositoryInterface());
-			if (!isCustomMethod(method) && !isBaseClassMethod(method)) {
+			if (isQueryMethodCandidate(method)) {
 				result.add(method);
 			}
 		}
@@ -175,6 +177,28 @@ class DefaultRepositoryInformation extends AbstractRepositoryMetadata implements
 		return Collections.unmodifiableSet(result);
 	}
 
+	/**
+	 * Checks whether the given method is a query method candidate.
+	 * 
+	 * @param method
+	 * @return
+	 */
+	private boolean isQueryMethodCandidate(Method method) {
+		return isQueryAnnotationPresentOn(method) || (!isCustomMethod(method) && !isBaseClassMethod(method));
+	}
+
+	/**
+	 * Checks whether the given method contains a custom store specific query annotation annotated with
+	 * {@link QueryAnnotation}. The method-hierarchy is also considered in the search for the annotation.
+	 * 
+	 * @param method
+	 * @return
+	 */
+	private boolean isQueryAnnotationPresentOn(Method method) {
+
+		return AnnotationUtils.findAnnotation(method, QueryAnnotation.class) != null;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.support.RepositoryInformation#isCustomMethod(java.lang.reflect.Method)