support annotaiton on constraint annotation

src/main/java/com/noorq/casser/mapping/MappingUtil.java

@@ -55,14 +55,36 @@ public final class MappingUtil {
 		
 		for (Annotation constraintAnnotation : getterMethod.getDeclaredAnnotations()) {
 			
+			list = addValidators(constraintAnnotation, list);
+			
 			Class<? extends Annotation> annotationType = constraintAnnotation.annotationType();
 			
-			Constraint constraint = annotationType.getDeclaredAnnotation(Constraint.class);
+			for (Annotation possibleConstraint : annotationType.getDeclaredAnnotations()) {
+				
+				list = addValidators(possibleConstraint, list);
 				
-			if (constraint == null) {
-				continue;
 			}
 			
+		}
+		
+		if (list == null) {
+			return EMPTY_VALIDATORS;
+		}
+		else {
+			return list.toArray(EMPTY_VALIDATORS);
+		}
+	}
+	
+	private static List<ConstraintValidator<? extends Annotation, ?>> addValidators(Annotation constraintAnnotation, List<ConstraintValidator<? extends Annotation, ?>> list) {
+		
+		Class<? extends Annotation> annotationType = constraintAnnotation.annotationType();
+		
+		for (Annotation possibleConstraint : annotationType.getDeclaredAnnotations()) {
+			
+			if (possibleConstraint instanceof Constraint) {
+				
+				Constraint constraint = (Constraint) possibleConstraint; 
+				
 				for (Class<? extends ConstraintValidator<?, ?>> clazz : constraint.validatedBy()) {
 
 					ConstraintValidator<? extends Annotation, ?> validator = ReflectionInstantiator.instantiateClass(clazz);
@@ -79,12 +101,10 @@ public final class MappingUtil {
 				
 			}
 			
-		if (list == null) {
-			return EMPTY_VALIDATORS;
-		}
-		else {
-			return list.toArray(EMPTY_VALIDATORS);
 		}
+		
+		return list;
+		
 	}
 	
 	public static Optional<IdentityName> getIndexName(Method getterMethod) {

src/test/java/com/noorq/casser/test/integration/core/simple/User.java

@@ -16,7 +16,6 @@
 package com.noorq.casser.test.integration.core.simple;
 
 import com.noorq.casser.mapping.annotation.Column;
-import com.noorq.casser.mapping.annotation.Constraints;
 import com.noorq.casser.mapping.annotation.PartitionKey;
 import com.noorq.casser.mapping.annotation.Table;
 
@@ -26,7 +25,7 @@ public interface User {
 	@PartitionKey
 	Long id();
 	
-	@Constraints.LowerCase
+	@Username
 	@Column("override_name")
 	String name();
 	

src/test/java/com/noorq/casser/test/integration/core/simple/Username.java

@@ -0,0 +1,33 @@
+/*
+ *      Copyright (C) 2015 Noorq, Inc.
+ *
+ *   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 com.noorq.casser.test.integration.core.simple;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import com.noorq.casser.mapping.annotation.Constraints;
+
+
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target(value = { ElementType.METHOD, ElementType.ANNOTATION_TYPE })
+@Constraints.LowerCase
+public @interface Username {
+
+}