@PathVariable supports 'required' attribute (for model attribute methods)

Issue: SPR-14646

spring-web/src/main/java/org/springframework/web/bind/annotation/PathVariable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -22,6 +22,8 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
+
 /**
  * Annotation which indicates that a method parameter should be bound to a URI template
  * variable. Supported for {@link RequestMapping} annotated handler methods in Servlet
@@ -32,6 +34,7 @@ import java.lang.annotation.Target;
  * then the map is populated with all path variable names and values.
  *
  * @author Arjen Poutsma
+ * @author Juergen Hoeller
  * @since 3.0
  * @see RequestMapping
  * @see org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter
@@ -42,8 +45,26 @@ import java.lang.annotation.Target;
 public @interface PathVariable {
 
 	/**
-	 * The URI template variable to bind to.
+	 * Alias for {@link #name}.
 	 */
+	@AliasFor("name")
 	String value() default "";
 
+	/**
+	 * The name of the path variable to bind to.
+	 * @since 4.3.3
+	 */
+	@AliasFor("value")
+	String name() default "";
+
+	/**
+	 * Whether the path variable is required.
+	 * <p>Defaults to {@code true}, leading to an exception being thrown if the path
+	 * variable is missing in the incoming request. Switch this to {@code false} if
+	 * you prefer a {@code null} or Java 8 {@code java.util.Optional} in this case.
+	 * e.g. on a {@code ModelAttribute} method which serves for different requests.
+	 * @since 4.3.3
+	 */
+	boolean required() default true;
+
 }