Polishing

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestPartMethodArgumentResolver.java

@@ -20,7 +20,6 @@ import java.lang.annotation.Annotation;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
-
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.Part;
 
@@ -52,18 +51,15 @@ import org.springframework.web.util.WebUtils;
 /**
  * Resolves the following method arguments:
  * <ul>
- * 	<li>Annotated with {@code @RequestPart}
- * 	<li>Of type {@link MultipartFile} in conjunction with Spring's
- *  {@link MultipartResolver} abstraction
- * 	<li>Of type {@code javax.servlet.http.Part} in conjunction with
- * 	Servlet 3.0 multipart requests
+ * <li>Annotated with {@code @RequestPart}
+ * <li>Of type {@link MultipartFile} in conjunction with Spring's {@link MultipartResolver} abstraction
+ * <li>Of type {@code javax.servlet.http.Part} in conjunction with Servlet 3.0 multipart requests
  * </ul>
  *
- * <p>When a parameter is annotated with {@code @RequestPart} the content of the
- * part is passed through an {@link HttpMessageConverter} to resolve the method
- * argument with the 'Content-Type' of the request part in mind. This is
- * analogous to what @{@link RequestBody} does to resolve an argument based on
- * the content of a regular request.
+ * <p>When a parameter is annotated with {@code @RequestPart}, the content of the part is
+ * passed through an {@link HttpMessageConverter} to resolve the method argument with the
+ * 'Content-Type' of the request part in mind. This is analogous to what @{@link RequestBody}
+ * does to resolve an argument based on the content of a regular request.
  *
  * <p>When a parameter is not annotated or the name of the part is not specified,
  * it is derived from the name of the method argument.
@@ -135,7 +131,8 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageConverterM
 		}
 		else if (isMultipartFileArray(parameter)) {
 			Assert.notNull(multipartRequest, "Expected MultipartHttpServletRequest: is a MultipartResolver configured?");
-			arg = multipartRequest.getFiles(partName).toArray(new MultipartFile[0]);
+			List<MultipartFile> files = multipartRequest.getFiles(partName);
+			arg = files.toArray(new MultipartFile[files.size()]);
 		}
 		else if ("javax.servlet.http.Part".equals(parameter.getParameterType().getName())) {
 			assertIsMultipartRequest(servletRequest);
@@ -184,33 +181,33 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageConverterM
 
 	private String getPartName(MethodParameter parameter) {
 		RequestPart annot = parameter.getParameterAnnotation(RequestPart.class);
-		String partName = (annot != null) ? annot.value() : "";
+		String partName = (annot != null ? annot.value() : "");
 		if (partName.length() == 0) {
 			partName = parameter.getParameterName();
-			Assert.notNull(partName, "Request part name for argument type [" + parameter.getParameterType().getName()
-					+ "] not available, and parameter name information not found in class file either.");
+			Assert.notNull(partName, "Request part name for argument type [" + parameter.getParameterType().getName() +
+					"] not specified, and parameter name information not found in class file either.");
 		}
 		return partName;
 	}
 
 	private boolean isMultipartFileCollection(MethodParameter parameter) {
 		Class<?> collectionType = getCollectionParameterType(parameter);
-		return ((collectionType != null) && collectionType.equals(MultipartFile.class));
-	}
-
-	private boolean isPartCollection(MethodParameter parameter) {
-		Class<?> collectionType = getCollectionParameterType(parameter);
-		return ((collectionType != null) && "javax.servlet.http.Part".equals(collectionType.getName()));
-	}
-
-	private boolean isPartArray(MethodParameter parameter) {
-		Class<?> paramType = parameter.getParameterType().getComponentType();
-		return ((paramType != null) && "javax.servlet.http.Part".equals(paramType.getName()));
+		return (collectionType != null && collectionType.equals(MultipartFile.class));
 	}
 
 	private boolean isMultipartFileArray(MethodParameter parameter) {
 		Class<?> paramType = parameter.getParameterType().getComponentType();
-		return ((paramType != null) && MultipartFile.class.equals(paramType));
+		return (paramType != null && MultipartFile.class.equals(paramType));
+	}
+
+	private boolean isPartCollection(MethodParameter parameter) {
+		Class<?> collectionType = getCollectionParameterType(parameter);
+		return (collectionType != null && "javax.servlet.http.Part".equals(collectionType.getName()));
+	}
+
+	private boolean isPartArray(MethodParameter parameter) {
+		Class<?> paramType = parameter.getParameterType().getComponentType();
+		return (paramType != null && "javax.servlet.http.Part".equals(paramType.getName()));
 	}
 
 	private Class<?> getCollectionParameterType(MethodParameter parameter) {
@@ -225,7 +222,6 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageConverterM
 	}
 
 	private void validate(WebDataBinder binder, MethodParameter parameter) throws MethodArgumentNotValidException {
-
 		Annotation[] annotations = parameter.getParameterAnnotations();
 		for (Annotation annot : annotations) {
 			if (annot.annotationType().getSimpleName().startsWith("Valid")) {
@@ -233,7 +229,7 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageConverterM
 				binder.validate(hints instanceof Object[] ? (Object[]) hints : new Object[] {hints});
 				BindingResult bindingResult = binder.getBindingResult();
 				if (bindingResult.hasErrors()) {
-					if (isBindExceptionRequired(binder, parameter)) {
+					if (isBindingErrorFatal(parameter)) {
 						throw new MethodArgumentNotValidException(parameter, bindingResult);
 					}
 				}
@@ -243,22 +239,25 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageConverterM
 
 	/**
 	 * Whether to raise a {@link MethodArgumentNotValidException} on validation errors.
-	 * @param binder the data binder used to perform data binding
 	 * @param parameter the method argument
-	 * @return {@code true} if the next method argument is not of type {@link Errors}.
+	 * @return {@code true} if the next method argument is not of type {@link Errors}
 	 */
-	private boolean isBindExceptionRequired(WebDataBinder binder, MethodParameter parameter) {
+	private boolean isBindingErrorFatal(MethodParameter parameter) {
 		int i = parameter.getParameterIndex();
 		Class<?>[] paramTypes = parameter.getMethod().getParameterTypes();
 		boolean hasBindingResult = (paramTypes.length > (i + 1) && Errors.class.isAssignableFrom(paramTypes[i + 1]));
-
 		return !hasBindingResult;
 	}
 
+
+	/**
+	 * Inner class to avoid hard-coded dependency on Servlet 3.0 Part type...
+	 */
 	private static class RequestPartResolver {
 
 		public static Object resolvePart(HttpServletRequest servletRequest) throws Exception {
-			return servletRequest.getParts().toArray(new Part[servletRequest.getParts().size()]);
+			Collection<Part> parts = servletRequest.getParts();
+			return parts.toArray(new Part[parts.size()]);
 		}
 	}