HandlerMethod evaluates ResponseStatus annotation for early caching

Issue: SPR-15227

spring-web/src/main/java/org/springframework/web/method/HandlerMethod.java

@@ -28,8 +28,10 @@ import org.springframework.core.GenericTypeResolver;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.SynthesizingMethodParameter;
+import org.springframework.http.HttpStatus;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
+import org.springframework.web.bind.annotation.ResponseStatus;
 
 /**
  * Encapsulates information about a handler method consisting of a
@@ -65,7 +67,11 @@ public class HandlerMethod {
 
 	private final MethodParameter[] parameters;
 
-	private final HandlerMethod resolvedFromHandlerMethod;
+	private HttpStatus responseStatus;
+
+	private String responseStatusReason;
+
+	private HandlerMethod resolvedFromHandlerMethod;
 
 
 	/**
@@ -80,7 +86,7 @@ public class HandlerMethod {
 		this.method = method;
 		this.bridgedMethod = BridgeMethodResolver.findBridgedMethod(method);
 		this.parameters = initMethodParameters();
-		this.resolvedFromHandlerMethod = null;
+		evaluateResponseStatus();
 	}
 
 	/**
@@ -96,7 +102,7 @@ public class HandlerMethod {
 		this.method = bean.getClass().getMethod(methodName, parameterTypes);
 		this.bridgedMethod = BridgeMethodResolver.findBridgedMethod(this.method);
 		this.parameters = initMethodParameters();
-		this.resolvedFromHandlerMethod = null;
+		evaluateResponseStatus();
 	}
 
 	/**
@@ -114,7 +120,7 @@ public class HandlerMethod {
 		this.method = method;
 		this.bridgedMethod = BridgeMethodResolver.findBridgedMethod(method);
 		this.parameters = initMethodParameters();
-		this.resolvedFromHandlerMethod = null;
+		evaluateResponseStatus();
 	}
 
 	/**
@@ -128,6 +134,8 @@ public class HandlerMethod {
 		this.method = handlerMethod.method;
 		this.bridgedMethod = handlerMethod.bridgedMethod;
 		this.parameters = handlerMethod.parameters;
+		this.responseStatus = handlerMethod.responseStatus;
+		this.responseStatusReason = handlerMethod.responseStatusReason;
 		this.resolvedFromHandlerMethod = handlerMethod.resolvedFromHandlerMethod;
 	}
 
@@ -143,6 +151,8 @@ public class HandlerMethod {
 		this.method = handlerMethod.method;
 		this.bridgedMethod = handlerMethod.bridgedMethod;
 		this.parameters = handlerMethod.parameters;
+		this.responseStatus = handlerMethod.responseStatus;
+		this.responseStatusReason = handlerMethod.responseStatusReason;
 		this.resolvedFromHandlerMethod = handlerMethod;
 	}
 
@@ -158,15 +168,27 @@ public class HandlerMethod {
 		return result;
 	}
 
+	private void evaluateResponseStatus() {
+		ResponseStatus annotation = getMethodAnnotation(ResponseStatus.class);
+		if (annotation == null) {
+			annotation = AnnotatedElementUtils.findMergedAnnotation(getBeanType(), ResponseStatus.class);
+		}
+		if (annotation != null) {
+			this.responseStatus = annotation.code();
+			this.responseStatusReason = annotation.reason();
+		}
+	}
+
+
 	/**
-	 * Returns the bean for this handler method.
+	 * Return the bean for this handler method.
 	 */
 	public Object getBean() {
 		return this.bean;
 	}
 
 	/**
-	 * Returns the method for this handler method.
+	 * Return the method for this handler method.
 	 */
 	public Method getMethod() {
 		return this.method;
@@ -190,18 +212,28 @@ public class HandlerMethod {
 	}
 
 	/**
-	 * Returns the method parameters for this handler method.
+	 * Return the method parameters for this handler method.
 	 */
 	public MethodParameter[] getMethodParameters() {
 		return this.parameters;
 	}
 
 	/**
-	 * Return the HandlerMethod from which this HandlerMethod instance was
-	 * resolved via {@link #createWithResolvedBean()}.
+	 * Return the specified response status, if any.
+	 * @since 4.3.8
+	 * @see ResponseStatus#code()
 	 */
-	public HandlerMethod getResolvedFromHandlerMethod() {
-		return this.resolvedFromHandlerMethod;
+	protected HttpStatus getResponseStatus() {
+		return this.responseStatus;
+	}
+
+	/**
+	 * Return the associated response status reason, if any.
+	 * @since 4.3.8
+	 * @see ResponseStatus#reason()
+	 */
+	protected String getResponseStatusReason() {
+		return this.responseStatusReason;
 	}
 
 	/**
@@ -219,14 +251,14 @@ public class HandlerMethod {
 	}
 
 	/**
-	 * Returns {@code true} if the method return type is void, {@code false} otherwise.
+	 * Return {@code true} if the method return type is void, {@code false} otherwise.
 	 */
 	public boolean isVoid() {
 		return Void.TYPE.equals(getReturnType().getParameterType());
 	}
 
 	/**
-	 * Returns a single annotation on the underlying method traversing its super methods
+	 * Return a single annotation on the underlying method traversing its super methods
 	 * if no annotation can be found on the given method itself.
 	 * <p>Also supports <em>merged</em> composed annotations with attribute
 	 * overrides as of Spring Framework 4.2.2.
@@ -248,6 +280,14 @@ public class HandlerMethod {
 		return AnnotatedElementUtils.hasAnnotation(this.method, annotationType);
 	}
 
+	/**
+	 * Return the HandlerMethod from which this HandlerMethod instance was
+	 * resolved via {@link #createWithResolvedBean()}.
+	 */
+	public HandlerMethod getResolvedFromHandlerMethod() {
+		return this.resolvedFromHandlerMethod;
+	}
+
 	/**
 	 * If the provided instance contains a bean name rather than an object instance,
 	 * the bean name is resolved before a {@link HandlerMethod} is created and returned.