Improve annotation methods in TypeDescriptor

- Use generic typing for getAnnotation()
- Add hasAnnoation() method
- Update existing code and tests to make use of changes

Issue: SPR-9744

spring-context/src/main/java/org/springframework/format/support/FormattingConversionService.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -211,7 +211,7 @@ public class FormattingConversionService extends GenericConversionService
 		}
 
 		public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
-			return sourceType.getAnnotation(annotationType) != null;
+			return sourceType.hasAnnotation(annotationType);
 		}
 
 		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
@@ -251,7 +251,7 @@ public class FormattingConversionService extends GenericConversionService
 		}
 
 		public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
-			return targetType.getAnnotation(annotationType) != null;
+			return targetType.hasAnnotation(annotationType);
 		}
 
 		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {

spring-core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -271,15 +271,25 @@ public class TypeDescriptor {
 		return this.annotations;
 	}
 
+	/**
+	 * Determine if this type descriptor has the specified annotation.
+	 * @param annotationType the annotation type
+	 * @return <tt>true</tt> if the annotation is present
+	 */
+	public boolean hasAnnotation(Class<? extends Annotation> annotationType) {
+		return getAnnotation(annotationType) != null;
+	}
+
 	/**
 	 * Obtain the annotation associated with this type descriptor of the specified type.
 	 * @param annotationType the annotation type
 	 * @return the annotation, or null if no such annotation exists on this type descriptor
 	 */
-	public Annotation getAnnotation(Class<? extends Annotation> annotationType) {
+	@SuppressWarnings("unchecked")
+	public <T extends Annotation> T getAnnotation(Class<T> annotationType) {
 		for (Annotation annotation : getAnnotations()) {
 			if (annotation.annotationType().equals(annotationType)) {
-				return annotation;
+				return (T) annotation;
 			}
 		}
 		return null;

spring-core/src/test/java/org/springframework/core/convert/TypeDescriptorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -191,15 +191,17 @@ public class TypeDescriptorTests {
 		assertEquals(String.class, t1.getType());
 		assertEquals(1, t1.getAnnotations().length);
 		assertNotNull(t1.getAnnotation(ParameterAnnotation.class));
+		assertTrue(t1.hasAnnotation(ParameterAnnotation.class));
+		assertEquals(123, t1.getAnnotation(ParameterAnnotation.class).value());
 	}
 
 	@Target({ElementType.PARAMETER})
 	@Retention(RetentionPolicy.RUNTIME)
 	public @interface ParameterAnnotation {
-
+		int value();
 	}
 
-	public void testAnnotatedMethod(@ParameterAnnotation String parameter) {
+	public void testAnnotatedMethod(@ParameterAnnotation(123) String parameter) {
 
 	}
 
@@ -297,6 +299,7 @@ public class TypeDescriptorTests {
 		assertEquals(List.class, desc.getType());
 		assertEquals(Integer.class, desc.getElementTypeDescriptor().getType());
 		assertNotNull(desc.getAnnotation(MethodAnnotation1.class));
+		assertTrue(desc.hasAnnotation(MethodAnnotation1.class));
 	}
 
 	public static class GenericClass<T> {