SPR-6301 - Support @RequestHeader on HttpHeaders parameters

org.springframework.web/src/main/java/org/springframework/web/bind/annotation/RequestMapping.java

@@ -77,12 +77,16 @@ import java.lang.annotation.Target;
  * <li>{@link RequestParam @RequestParam} annotated parameters for access to
  * specific Servlet/Portlet request parameters. Parameter values will be
  * converted to the declared method argument type. Additionally,
- * {@code RequestParam @RequestParam} can be used on a {@link java.util.Map Map} or
- * {@link org.springframework.util.MultiValueMap MultiValueMap} to gain access
- * to all request parameters. 
+ * {@code @RequestParam} can be used on a {@link java.util.Map Map&lt;String, String&gt;} or
+ * {@link org.springframework.util.MultiValueMap MultiValueMap&lt;String, String&gt;}
+ * method parameter to gain access to all request parameters.
  * <li>{@link RequestHeader @RequestHeader} annotated parameters for access to
  * specific Servlet/Portlet request HTTP headers. Parameter values will be
- * converted to the declared method argument type.
+ * converted to the declared method argument type. Additionally,
+ * {@code @RequestHeader} can be used on a {@link java.util.Map Map&lt;String, String&gt;},
+ * {@link org.springframework.util.MultiValueMap MultiValueMap&lt;String, String&gt;}, or
+ * {@link org.springframework.http.HttpHeaders HttpHeaders} method parameter to
+ * gain access to all request headers.
  * <li>{@link RequestBody @RequestBody} annotated parameters for access to
  * the Servlet request HTTP contents. Parameter values will be
  * converted to the declared method argument type using 

org.springframework.web/src/main/java/org/springframework/web/bind/annotation/support/HandlerMethodInvoker.java

@@ -27,6 +27,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.LinkedHashMap;
+import java.util.Iterator;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -41,6 +42,7 @@ import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.http.HttpInputMessage;
 import org.springframework.http.MediaType;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.ui.ExtendedModelMap;
 import org.springframework.ui.Model;
@@ -457,11 +459,15 @@ public class HandlerMethodInvoker {
 		}
 	}
 
+	@SuppressWarnings("unchecked")
 	private Object resolveRequestHeader(String headerName, boolean required, String defaultValue,
 			MethodParameter methodParam, NativeWebRequest webRequest, Object handlerForInitBinderCall)
 			throws Exception {
 
 		Class<?> paramType = methodParam.getParameterType();
+		if (Map.class.isAssignableFrom(paramType)) {
+			return resolveRequestHeaderMap((Class<? extends Map>) paramType, webRequest);
+		}
 		if (headerName.length() == 0) {
 			headerName = getRequiredParameterName(methodParam);
 		}
@@ -484,6 +490,34 @@ public class HandlerMethodInvoker {
 		return binder.convertIfNecessary(headerValue, paramType, methodParam);
 	}
 
+	private Map resolveRequestHeaderMap(Class<? extends Map> mapType, NativeWebRequest webRequest) {
+		if (MultiValueMap.class.isAssignableFrom(mapType)) {
+			MultiValueMap<String, String> result;
+			if (HttpHeaders.class.isAssignableFrom(mapType)) {
+				result = new HttpHeaders();
+			} else {
+				result = new LinkedMultiValueMap<String, String>();
+			}
+			for (Iterator<String> iterator = webRequest.getHeaderNames(); iterator.hasNext();) {
+				String headerName = iterator.next();
+				for (String headerValue : webRequest.getHeaderValues(headerName)) {
+					result.add(headerName, headerValue);
+				}
+			}
+			return result;
+		}
+		else {
+			Map<String, String> result = new LinkedHashMap<String, String>();
+			for (Iterator<String> iterator = webRequest.getHeaderNames(); iterator.hasNext();) {
+				String headerName = iterator.next();
+				String headerValue = webRequest.getHeader(headerName);
+				result.put(headerName, headerValue);
+			}
+			return result;
+		}
+	}
+
+
 	/**
 	 * Resolves the given {@link RequestBody @RequestBody} annotation.
 	 */

org.springframework.web/src/main/java/org/springframework/web/context/request/FacesWebRequest.java

@@ -72,6 +72,10 @@ public class FacesWebRequest extends FacesRequestAttributes implements NativeWeb
 		return getExternalContext().getRequestHeaderValuesMap().get(headerName);
 	}
 
+	public Iterator<String> getHeaderNames() {
+		return getExternalContext().getRequestHeaderMap().keySet().iterator();
+	}
+
 	public String getParameter(String paramName) {
 		return getExternalContext().getRequestParameterMap().get(paramName);
 	}

org.springframework.web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java

@@ -102,6 +102,11 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 		return (!ObjectUtils.isEmpty(headerValues) ? headerValues : null);
 	}
 
+	@SuppressWarnings("unchecked")
+	public Iterator<String> getHeaderNames() {
+		return CollectionUtils.toIterator(getRequest().getHeaderNames());
+	}
+
 	public String getParameter(String paramName) {
 		return getRequest().getParameter(paramName);
 	}

org.springframework.web/src/main/java/org/springframework/web/context/request/WebRequest.java

@@ -47,6 +47,13 @@ public interface WebRequest extends RequestAttributes {
 	 */
 	String[] getHeaderValues(String headerName);
 
+	/**
+	 * Return a Iterator over request header names.
+	 * @see javax.servlet.http.HttpServletRequest#getHeaderNames()
+	 * @since 3.0
+	 */
+	Iterator<String> getHeaderNames();
+
 	/**
 	 * Return the request parameter of the given name, or <code>null</code> if none.
 	 * <p>Retrieves the first parameter value in case of a multi-value parameter.