Consistent use of empty enumerations

Author: jhoeller

spring-test/src/main/java/org/springframework/mock/web/MockServletContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 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.
@@ -25,7 +25,6 @@
 import java.util.Enumeration;
 import java.util.EventListener;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -144,7 +143,7 @@ public class MockServletContext implements ServletContext {
 
 	private String servletContextName = "MockServletContext";
 
-	private final Set<String> declaredRoles = new HashSet<String>();
+	private final Set<String> declaredRoles = new LinkedHashSet<String>();
 
 	private Set<SessionTrackingMode> sessionTrackingModes;
 
@@ -370,7 +369,6 @@ public RequestDispatcher getNamedDispatcher(String path) {
 	/**
 	 * Register a {@link RequestDispatcher} (typically a {@link MockRequestDispatcher})
 	 * that acts as a wrapper for the named Servlet.
-	 *
 	 * @param name the name of the wrapped Servlet
 	 * @param requestDispatcher the dispatcher that wraps the named Servlet
 	 * @see #getNamedDispatcher
@@ -384,7 +382,6 @@ public void registerNamedDispatcher(String name, RequestDispatcher requestDispat
 
 	/**
 	 * Unregister the {@link RequestDispatcher} with the given name.
-	 *
 	 * @param name the name of the dispatcher to unregister
 	 * @see #getNamedDispatcher
 	 * @see #registerNamedDispatcher
@@ -429,13 +426,13 @@ public Servlet getServlet(String name) {
 	@Override
 	@Deprecated
 	public Enumeration<Servlet> getServlets() {
-		return Collections.enumeration(new HashSet<Servlet>());
+		return Collections.enumeration(Collections.<Servlet>emptySet());
 	}
 
 	@Override
 	@Deprecated
 	public Enumeration<String> getServletNames() {
-		return Collections.enumeration(new HashSet<String>());
+		return Collections.enumeration(Collections.<String>emptySet());
 	}
 
 	@Override

spring-test/src/main/java/org/springframework/mock/web/portlet/ServletWrappingPortletContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 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.
@@ -21,7 +21,6 @@
 import java.net.URL;
 import java.util.Collections;
 import java.util.Enumeration;
-import java.util.HashSet;
 import java.util.Set;
 import javax.portlet.PortletContext;
 import javax.portlet.PortletRequestDispatcher;
@@ -156,7 +155,7 @@ public String getPortletContextName() {
 
 	@Override
 	public Enumeration<String> getContainerRuntimeOptions() {
-		return Collections.enumeration(new HashSet<String>());
+		return Collections.enumeration(Collections.<String>emptySet());
 	}
 
 }

spring-web/src/main/java/org/springframework/web/filter/ForwardedHeaderFilter.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.web.filter;
 
 import java.io.IOException;
@@ -37,7 +38,6 @@
 import org.springframework.web.util.UriComponentsBuilder;
 import org.springframework.web.util.UrlPathHelper;
 
-
 /**
  * Filter that wraps the request in order to override its
  * {@link HttpServletRequest#getServerName() getServerName()},
@@ -70,11 +70,9 @@ public class ForwardedHeaderFilter extends OncePerRequestFilter {
 	/**
 	 * Configure a contextPath value that will replace the contextPath of
 	 * proxy-forwarded requests.
-	 *
 	 * <p>This is useful when external clients are not aware of the application
 	 * context path. However a proxy forwards the request to a URL that includes
 	 * a contextPath.
-	 *
 	 * @param contextPath the context path; the given value will be sanitized to
 	 * ensure it starts with a '/' but does not end with one, or if the context
 	 * path is empty (default, root context) it is left as-is.
@@ -117,10 +115,6 @@ protected void doFilterInternal(HttpServletRequest request, HttpServletResponse
 
 	private static class ForwardedHeaderRequestWrapper extends HttpServletRequestWrapper {
 
-		public static final Enumeration<String> EMPTY_HEADER_VALUES =
-				Collections.enumeration(Collections.<String>emptyList());
-
-
 		private final String scheme;
 
 		private final boolean secure;
@@ -137,7 +131,6 @@ private static class ForwardedHeaderRequestWrapper extends HttpServletRequestWra
 
 		private final Map<String, List<String>> headers;
 
-
 		public ForwardedHeaderRequestWrapper(HttpServletRequest request, ContextPathHelper pathHelper) {
 			super(request);
 
@@ -228,7 +221,7 @@ public String getHeader(String name) {
 		@Override
 		public Enumeration<String> getHeaders(String name) {
 			List<String> value = this.headers.get(name);
-			return (CollectionUtils.isEmpty(value) ? EMPTY_HEADER_VALUES : Collections.enumeration(value));
+			return (Collections.enumeration(value != null ? value : Collections.<String>emptySet()));
 		}
 
 		@Override
@@ -244,7 +237,6 @@ private static class ContextPathHelper {
 
 		private final UrlPathHelper urlPathHelper;
 
-
 		public ContextPathHelper(String contextPath) {
 			Assert.notNull(contextPath);
 			this.contextPath = sanitizeContextPath(contextPath);

spring-web/src/test/java/org/springframework/mock/web/test/MockServletContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 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.
@@ -25,7 +25,6 @@
 import java.util.Enumeration;
 import java.util.EventListener;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -144,7 +143,7 @@ public class MockServletContext implements ServletContext {
 
 	private String servletContextName = "MockServletContext";
 
-	private final Set<String> declaredRoles = new HashSet<String>();
+	private final Set<String> declaredRoles = new LinkedHashSet<String>();
 
 	private Set<SessionTrackingMode> sessionTrackingModes;
 
@@ -370,7 +369,6 @@ public RequestDispatcher getNamedDispatcher(String path) {
 	/**
 	 * Register a {@link RequestDispatcher} (typically a {@link MockRequestDispatcher})
 	 * that acts as a wrapper for the named Servlet.
-	 *
 	 * @param name the name of the wrapped Servlet
 	 * @param requestDispatcher the dispatcher that wraps the named Servlet
 	 * @see #getNamedDispatcher
@@ -384,7 +382,6 @@ public void registerNamedDispatcher(String name, RequestDispatcher requestDispat
 
 	/**
 	 * Unregister the {@link RequestDispatcher} with the given name.
-	 *
 	 * @param name the name of the dispatcher to unregister
 	 * @see #getNamedDispatcher
 	 * @see #registerNamedDispatcher
@@ -429,13 +426,13 @@ public Servlet getServlet(String name) {
 	@Override
 	@Deprecated
 	public Enumeration<Servlet> getServlets() {
-		return Collections.enumeration(new HashSet<Servlet>());
+		return Collections.enumeration(Collections.<Servlet>emptySet());
 	}
 
 	@Override
 	@Deprecated
 	public Enumeration<String> getServletNames() {
-		return Collections.enumeration(new HashSet<String>());
+		return Collections.enumeration(Collections.<String>emptySet());
 	}
 
 	@Override

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/handler/SimplePortletPostProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 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.
@@ -18,7 +18,6 @@
 
 import java.util.Collections;
 import java.util.Enumeration;
-import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import java.util.ResourceBundle;
@@ -175,7 +174,7 @@ public String getInitParameter(String paramName) {
 
 		@Override
 		public Enumeration<String> getInitParameterNames() {
-			return Collections.enumeration(new HashSet<String>());
+			return Collections.enumeration(Collections.<String>emptySet());
 		}
 
 		@Override
@@ -185,7 +184,7 @@ public ResourceBundle getResourceBundle(Locale locale) {
 
 		@Override
 		public Enumeration<String> getPublicRenderParameterNames() {
-			return Collections.enumeration(new HashSet<String>());
+			return Collections.enumeration(Collections.<String>emptySet());
 		}
 
 		@Override
@@ -195,17 +194,17 @@ public String getDefaultNamespace() {
 
 		@Override
 		public Enumeration<QName> getPublishingEventQNames() {
-			return Collections.enumeration(new HashSet<QName>());
+			return Collections.enumeration(Collections.<QName>emptySet());
 		}
 
 		@Override
 		public Enumeration<QName> getProcessingEventQNames() {
-			return Collections.enumeration(new HashSet<QName>());
+			return Collections.enumeration(Collections.<QName>emptySet());
 		}
 
 		@Override
 		public Enumeration<Locale> getSupportedLocales() {
-			return Collections.enumeration(new HashSet<Locale>());
+			return Collections.enumeration(Collections.<Locale>emptySet());
 		}
 
 		@Override

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/mvc/PortletWrappingController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 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.
@@ -18,7 +18,6 @@
 
 import java.util.Collections;
 import java.util.Enumeration;
-import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.Locale;
 import java.util.Map;
@@ -288,7 +287,7 @@ public ResourceBundle getResourceBundle(Locale locale) {
 
 		@Override
 		public Enumeration<String> getPublicRenderParameterNames() {
-			return Collections.enumeration(new HashSet<String>());
+			return Collections.enumeration(Collections.<String>emptySet());
 		}
 
 		@Override
@@ -298,17 +297,17 @@ public String getDefaultNamespace() {
 
 		@Override
 		public Enumeration<QName> getPublishingEventQNames() {
-			return Collections.enumeration(new HashSet<QName>());
+			return Collections.enumeration(Collections.<QName>emptySet());
 		}
 
 		@Override
 		public Enumeration<QName> getProcessingEventQNames() {
-			return Collections.enumeration(new HashSet<QName>());
+			return Collections.enumeration(Collections.<QName>emptySet());
 		}
 
 		@Override
 		public Enumeration<Locale> getSupportedLocales() {
-			return Collections.enumeration(new HashSet<Locale>());
+			return Collections.enumeration(Collections.<Locale>emptySet());
 		}
 
 		@Override

spring-webmvc-portlet/src/test/java/org/springframework/mock/web/portlet/ServletWrappingPortletContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 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.
@@ -21,7 +21,6 @@
 import java.net.URL;
 import java.util.Collections;
 import java.util.Enumeration;
-import java.util.HashSet;
 import java.util.Set;
 import javax.portlet.PortletContext;
 import javax.portlet.PortletRequestDispatcher;
@@ -35,7 +34,7 @@
  *
  * @author Juergen Hoeller
  * @since 3.0
- * @see org.springframework.mock.web.portlet.MockPortletContext
+ * @see MockPortletContext
  */
 public class ServletWrappingPortletContext implements PortletContext {
 
@@ -156,7 +155,7 @@ public String getPortletContextName() {
 
 	@Override
 	public Enumeration<String> getContainerRuntimeOptions() {
-		return Collections.enumeration(new HashSet<String>());
+		return Collections.enumeration(Collections.<String>emptySet());
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleServletPostProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 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.
@@ -18,7 +18,6 @@
 
 import java.util.Collections;
 import java.util.Enumeration;
-import java.util.HashSet;
 import javax.servlet.Servlet;
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletContext;
@@ -164,7 +163,7 @@ public String getInitParameter(String paramName) {
 
 		@Override
 		public Enumeration<String> getInitParameterNames() {
-			return Collections.enumeration(new HashSet<String>());
+			return Collections.enumeration(Collections.<String>emptySet());
 		}
 	}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/view/freemarker/FreeMarkerView.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 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.
@@ -20,7 +20,6 @@
 import java.io.IOException;
 import java.util.Collections;
 import java.util.Enumeration;
-import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import javax.servlet.GenericServlet;
@@ -406,7 +405,7 @@ public String getInitParameter(String paramName) {
 
 		@Override
 		public Enumeration<String> getInitParameterNames() {
-			return Collections.enumeration(new HashSet<String>());
+			return Collections.enumeration(Collections.<String>emptySet());
 		}
 	}