Use consistent class design

Update all classes so that inner classes are always last. Also
ensure that utility classes are always final and have a private
constructor and make exceptions final whenever possible.

Issue: SPR-16968

spring-web/src/main/java/org/springframework/http/ContentDisposition.java

@@ -39,7 +39,7 @@ import static java.time.format.DateTimeFormatter.*;
  * @since 5.0
  * @see <a href="https://tools.ietf.org/html/rfc2183">RFC 2183</a>
  */
-public class ContentDisposition {
+public final class ContentDisposition {
 
 	@Nullable
 	private final String type;

spring-web/src/main/java/org/springframework/http/InvalidMediaTypeException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -28,7 +28,7 @@ import org.springframework.util.InvalidMimeTypeException;
 @SuppressWarnings("serial")
 public class InvalidMediaTypeException extends IllegalArgumentException {
 
-	private String mediaType;
+	private final String mediaType;
 
 
 	/**

spring-web/src/main/java/org/springframework/http/MediaTypeFactory.java

@@ -40,13 +40,17 @@ import org.springframework.util.StringUtils;
  * @author Arjen Poutsma
  * @since 5.0
  */
-public class MediaTypeFactory {
+public final class MediaTypeFactory {
 
 	private static final String MIME_TYPES_FILE_NAME = "/org/springframework/http/mime.types";
 
 	private static final MultiValueMap<String, MediaType> fileExtensionToMediaTypes = parseMimeTypes();
 
 
+	private MediaTypeFactory() {
+	}
+
+
 	/**
 	 * Parse the {@code mime.types} file found in the resources. Format is:
 	 * <code>

spring-web/src/main/java/org/springframework/http/codec/CodecConfigurerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -36,7 +36,7 @@ import org.springframework.util.ClassUtils;
  * @see ClientCodecConfigurer#create()
  * @see ServerCodecConfigurer#create()
  */
-class CodecConfigurerFactory {
+final class CodecConfigurerFactory {
 
 	private static final String DEFAULT_CONFIGURERS_PATH = "CodecConfigurer.properties";
 
@@ -59,6 +59,10 @@ class CodecConfigurerFactory {
 	}
 
 
+	private CodecConfigurerFactory() {
+	}
+
+
 	@SuppressWarnings("unchecked")
 	public static <T extends CodecConfigurer> T create(Class<T> ifc) {
 		Class<?> impl = defaultCodecConfigurers.get(ifc);

spring-web/src/main/java/org/springframework/http/codec/ServerSentEvent.java

@@ -32,7 +32,7 @@ import org.springframework.lang.Nullable;
  * @see ServerSentEventHttpMessageWriter
  * @see <a href="https://www.w3.org/TR/eventsource/">Server-Sent Events W3C recommendation</a>
  */
-public class ServerSentEvent<T> {
+public final class ServerSentEvent<T> {
 
 	@Nullable
     private final String id;

spring-web/src/main/java/org/springframework/http/codec/json/Jackson2Tokenizer.java

@@ -42,7 +42,7 @@ import org.springframework.util.Assert;
  * @author Arjen Poutsma
  * @since 5.0
  */
-class Jackson2Tokenizer {
+final class Jackson2Tokenizer {
 
 	private final JsonParser parser;
 

spring-web/src/main/java/org/springframework/http/server/DefaultPathContainer.java

@@ -36,7 +36,7 @@ import org.springframework.util.StringUtils;
  * @author Rossen Stoyanchev
  * @since 5.0
  */
-class DefaultPathContainer implements PathContainer {
+final class DefaultPathContainer implements PathContainer {
 
 	private static final MultiValueMap<String, String> EMPTY_MAP = new LinkedMultiValueMap<>(0);
 

spring-web/src/main/java/org/springframework/web/HttpRequestMethodNotSupportedException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -37,10 +37,10 @@ import org.springframework.util.StringUtils;
 @SuppressWarnings("serial")
 public class HttpRequestMethodNotSupportedException extends ServletException {
 
-	private String method;
+	private final String method;
 
 	@Nullable
-	private String[] supportedMethods;
+	private final String[] supportedMethods;
 
 
 	/**

spring-web/src/main/java/org/springframework/web/HttpSessionRequiredException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -30,7 +30,7 @@ import org.springframework.lang.Nullable;
 public class HttpSessionRequiredException extends ServletException {
 
 	@Nullable
-	private String expectedAttribute;
+	private final String expectedAttribute;
 
 
 	/**
@@ -39,6 +39,7 @@ public class HttpSessionRequiredException extends ServletException {
 	 */
 	public HttpSessionRequiredException(String msg) {
 		super(msg);
+		this.expectedAttribute = null;
 	}
 
 	/**

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -30,7 +30,7 @@ import org.springframework.web.util.WebUtils;
  * @author Rossen Stoyanchev
  * @since 4.3.10
  */
-class RelativeRedirectResponseWrapper extends HttpServletResponseWrapper {
+final class RelativeRedirectResponseWrapper extends HttpServletResponseWrapper {
 
 	private final HttpStatus redirectStatus;
 

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

@@ -46,7 +46,7 @@ import org.springframework.util.StringUtils;
  * @author Rossen Stoyanchev
  * @since 5.1
  */
-public class  HandlerTypePredicate implements Predicate<Class<?>> {
+public final class HandlerTypePredicate implements Predicate<Class<?>> {
 
 	private final Set<String> basePackages;
 

spring-web/src/main/java/org/springframework/web/method/annotation/AbstractCookieValueMethodArgumentResolver.java

@@ -71,7 +71,7 @@ public abstract class AbstractCookieValueMethodArgumentResolver extends Abstract
 	}
 
 
-	private static class CookieValueNamedValueInfo extends NamedValueInfo {
+	private static final class CookieValueNamedValueInfo extends NamedValueInfo {
 
 		private CookieValueNamedValueInfo(CookieValue annotation) {
 			super(annotation.name(), annotation.required(), annotation.defaultValue());

spring-web/src/main/java/org/springframework/web/method/annotation/ExpressionValueMethodArgumentResolver.java

@@ -77,7 +77,7 @@ public class ExpressionValueMethodArgumentResolver extends AbstractNamedValueMet
 	}
 
 
-	private static class ExpressionValueNamedValueInfo extends NamedValueInfo {
+	private static final class ExpressionValueNamedValueInfo extends NamedValueInfo {
 
 		private ExpressionValueNamedValueInfo(Value annotation) {
 			super("@Value", false, annotation.value());

spring-web/src/main/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolver.java

@@ -88,7 +88,7 @@ public class RequestHeaderMethodArgumentResolver extends AbstractNamedValueMetho
 	}
 
 
-	private static class RequestHeaderNamedValueInfo extends NamedValueInfo {
+	private static final class RequestHeaderNamedValueInfo extends NamedValueInfo {
 
 		private RequestHeaderNamedValueInfo(RequestHeader annotation) {
 			super(annotation.name(), annotation.required(), annotation.defaultValue());

spring-web/src/main/java/org/springframework/web/server/adapter/WebHttpHandlerBuilder.java

@@ -62,7 +62,7 @@ import org.springframework.web.server.session.WebSessionManager;
  * @since 5.0
  * @see HttpWebHandlerAdapter
  */
-public class WebHttpHandlerBuilder {
+public final class WebHttpHandlerBuilder {
 
 	/** Well-known name for the target WebHandler in the bean factory. */
 	public static final String WEB_HANDLER_BEAN_NAME = "webHandler";

spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java

@@ -53,6 +53,50 @@ final class HierarchicalUriComponents extends UriComponents {
 
 	private static final String PATH_DELIMITER_STRING = "/";
 
+	/**
+	 * Represents an empty path.
+	 */
+	static final PathComponent NULL_PATH_COMPONENT = new PathComponent() {
+
+		@Override
+		public String getPath() {
+			return "";
+		}
+
+		@Override
+		public List<String> getPathSegments() {
+			return Collections.emptyList();
+		}
+
+		@Override
+		public PathComponent encode(Charset charset) {
+			return this;
+		}
+
+		@Override
+		public void verify() {
+		}
+
+		@Override
+		public PathComponent expand(UriTemplateVariables uriVariables) {
+			return this;
+		}
+
+		@Override
+		public void copyToUriComponentsBuilder(UriComponentsBuilder builder) {
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			return (this == obj);
+		}
+
+		@Override
+		public int hashCode() {
+			return getClass().hashCode();
+		}
+	};
+
 
 	@Nullable
 	private final String userInfo;
@@ -862,43 +906,6 @@ final class HierarchicalUriComponents extends UriComponents {
 	}
 
 
-	/**
-	 * Represents an empty path.
-	 */
-	static final PathComponent NULL_PATH_COMPONENT = new PathComponent() {
-		@Override
-		public String getPath() {
-			return "";
-		}
-		@Override
-		public List<String> getPathSegments() {
-			return Collections.emptyList();
-		}
-		@Override
-		public PathComponent encode(Charset charset) {
-			return this;
-		}
-		@Override
-		public void verify() {
-		}
-		@Override
-		public PathComponent expand(UriTemplateVariables uriVariables) {
-			return this;
-		}
-		@Override
-		public void copyToUriComponentsBuilder(UriComponentsBuilder builder) {
-		}
-		@Override
-		public boolean equals(Object obj) {
-			return (this == obj);
-		}
-		@Override
-		public int hashCode() {
-			return getClass().hashCode();
-		}
-	};
-
-
 	private static class QueryUriTemplateVariables implements UriTemplateVariables {
 
 		private final UriTemplateVariables delegate;

spring-web/src/main/java/org/springframework/web/util/JavaScriptUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -29,7 +29,12 @@ package org.springframework.web.util;
  * @author Rossen Stoyanchev
  * @since 1.1.1
  */
-public class JavaScriptUtils {
+public final class JavaScriptUtils {
+
+
+	private JavaScriptUtils() {
+	}
+
 
 	/**
 	 * Turn JavaScript special characters into escaped characters.

spring-web/src/main/java/org/springframework/web/util/UriTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -170,7 +170,7 @@ public class UriTemplate implements Serializable {
 	/**
 	 * Helper to extract variable names and regex for matching to actual URLs.
 	 */
-	private static class TemplateInfo {
+	private static final class TemplateInfo {
 
 		private final List<String> variableNames;
 

spring-web/src/main/java/org/springframework/web/util/pattern/PathPattern.java

@@ -73,6 +73,25 @@ public class PathPattern implements Comparable<PathPattern> {
 
 	private static final PathContainer EMPTY_PATH = PathContainer.parsePath("");
 
+	/**
+	 * Comparator that sorts patterns by specificity as follows:
+	 * <ol>
+	 * <li>Null instances are last.
+	 * <li>Catch-all patterns are last.
+	 * <li>If both patterns are catch-all, consider the length (longer wins).
+	 * <li>Compare wildcard and captured variable count (lower wins).
+	 * <li>Consider length (longer wins)
+	 * </ol>
+	 */
+	public static final Comparator<PathPattern> SPECIFICITY_COMPARATOR =
+			Comparator.nullsLast(
+					Comparator.<PathPattern>
+							comparingInt(p -> p.isCatchAll() ? 1 : 0)
+							.thenComparingInt(p -> p.isCatchAll() ? scoreByNormalizedLength(p) : 0)
+							.thenComparingInt(PathPattern::getScore)
+							.thenComparingInt(PathPattern::scoreByNormalizedLength)
+			);
+
 
 	/** The text of the parsed pattern. */
 	private final String patternString;
@@ -408,97 +427,6 @@ public class PathPattern implements Comparable<PathPattern> {
 		return this.patternString;
 	}
 
-
-	/**
-	 * Holder for URI variables and path parameters (matrix variables) extracted
-	 * based on the pattern for a given matched path.
-	 */
-	public static class PathMatchInfo {
-
-		private static final PathMatchInfo EMPTY =
-				new PathMatchInfo(Collections.emptyMap(), Collections.emptyMap());
-
-
-		private final Map<String, String> uriVariables;
-
-		private final Map<String, MultiValueMap<String, String>> matrixVariables;
-
-
-		PathMatchInfo(Map<String, String> uriVars,
-				@Nullable Map<String, MultiValueMap<String, String>> matrixVars) {
-
-			this.uriVariables = Collections.unmodifiableMap(uriVars);
-			this.matrixVariables = matrixVars != null ?
-					Collections.unmodifiableMap(matrixVars) : Collections.emptyMap();
-		}
-
-
-		/**
-		 * Return the extracted URI variables.
-		 */
-		public Map<String, String> getUriVariables() {
-			return this.uriVariables;
-		}
-
-		/**
-		 * Return maps of matrix variables per path segment, keyed off by URI
-		 * variable name.
-		 */
-		public Map<String, MultiValueMap<String, String>> getMatrixVariables() {
-			return this.matrixVariables;
-		}
-
-		@Override
-		public String toString() {
-			return "PathMatchInfo[uriVariables=" + this.uriVariables + ", " +
-					"matrixVariables=" + this.matrixVariables + "]";
-		}
-	}
-
-	/**
-	 * Holder for the result of a match on the start of a pattern.
-	 * Provides access to the remaining path not matched to the pattern as well
-	 * as any variables bound in that first part that was matched.
-	 */
-	public static class PathRemainingMatchInfo {
-
-		private final PathContainer pathRemaining;
-
-		private final PathMatchInfo pathMatchInfo;
-
-
-		PathRemainingMatchInfo(PathContainer pathRemaining) {
-			this(pathRemaining, PathMatchInfo.EMPTY);
-		}
-
-		PathRemainingMatchInfo(PathContainer pathRemaining, PathMatchInfo pathMatchInfo) {
-			this.pathRemaining = pathRemaining;
-			this.pathMatchInfo = pathMatchInfo;
-		}
-
-		/**
-		 * Return the part of a path that was not matched by a pattern.
-		 */
-		public PathContainer getPathRemaining() {
-			return this.pathRemaining;
-		}
-
-		/**
-		 * Return variables that were bound in the part of the path that was
-		 * successfully matched or an empty map.
-		 */
-		public Map<String, String> getUriVariables() {
-			return this.pathMatchInfo.getUriVariables();
-		}
-
-		/**
-		 * Return the path parameters for each bound variable.
-		 */
-		public Map<String, MultiValueMap<String, String>> getMatrixVariables() {
-			return this.pathMatchInfo.getMatrixVariables();
-		}
-	}
-
 	int getScore() {
 		return this.score;
 	}
@@ -554,6 +482,138 @@ public class PathPattern implements Comparable<PathPattern> {
 		return this.head;
 	}
 
+	/**
+	 * Join two paths together including a separator if necessary.
+	 * Extraneous separators are removed (if the first path
+	 * ends with one and the second path starts with one).
+	 * @param path1 first path
+	 * @param path2 second path
+	 * @return joined path that may include separator if necessary
+	 */
+	private String concat(String path1, String path2) {
+		boolean path1EndsWithSeparator = (path1.charAt(path1.length() - 1) == this.separator);
+		boolean path2StartsWithSeparator = (path2.charAt(0) == this.separator);
+		if (path1EndsWithSeparator && path2StartsWithSeparator) {
+			return path1 + path2.substring(1);
+		}
+		else if (path1EndsWithSeparator || path2StartsWithSeparator) {
+			return path1 + path2;
+		}
+		else {
+			return path1 + this.separator + path2;
+		}
+	}
+
+	/**
+	 * Return if the container is not null and has more than zero elements.
+	 * @param container a path container
+	 * @return {@code true} has more than zero elements
+	 */
+	private boolean hasLength(@Nullable PathContainer container) {
+		return container != null && container.elements().size() > 0;
+	}
+
+	private static int scoreByNormalizedLength(PathPattern pattern) {
+		return -pattern.getNormalizedLength();
+	}
+
+	private boolean pathContainerIsJustSeparator(PathContainer pathContainer) {
+		return pathContainer.value().length() == 1 &&
+				pathContainer.value().charAt(0) == separator;
+	}
+
+	/**
+	 * Holder for URI variables and path parameters (matrix variables) extracted
+	 * based on the pattern for a given matched path.
+	 */
+	public static class PathMatchInfo {
+
+		private static final PathMatchInfo EMPTY =
+				new PathMatchInfo(Collections.emptyMap(), Collections.emptyMap());
+
+
+		private final Map<String, String> uriVariables;
+
+		private final Map<String, MultiValueMap<String, String>> matrixVariables;
+
+
+		PathMatchInfo(Map<String, String> uriVars,
+				@Nullable Map<String, MultiValueMap<String, String>> matrixVars) {
+
+			this.uriVariables = Collections.unmodifiableMap(uriVars);
+			this.matrixVariables = matrixVars != null ?
+					Collections.unmodifiableMap(matrixVars) : Collections.emptyMap();
+		}
+
+
+		/**
+		 * Return the extracted URI variables.
+		 */
+		public Map<String, String> getUriVariables() {
+			return this.uriVariables;
+		}
+
+		/**
+		 * Return maps of matrix variables per path segment, keyed off by URI
+		 * variable name.
+		 */
+		public Map<String, MultiValueMap<String, String>> getMatrixVariables() {
+			return this.matrixVariables;
+		}
+
+		@Override
+		public String toString() {
+			return "PathMatchInfo[uriVariables=" + this.uriVariables + ", " +
+					"matrixVariables=" + this.matrixVariables + "]";
+		}
+	}
+
+
+	/**
+	 * Holder for the result of a match on the start of a pattern.
+	 * Provides access to the remaining path not matched to the pattern as well
+	 * as any variables bound in that first part that was matched.
+	 */
+	public static class PathRemainingMatchInfo {
+
+		private final PathContainer pathRemaining;
+
+		private final PathMatchInfo pathMatchInfo;
+
+
+		PathRemainingMatchInfo(PathContainer pathRemaining) {
+			this(pathRemaining, PathMatchInfo.EMPTY);
+		}
+
+		PathRemainingMatchInfo(PathContainer pathRemaining, PathMatchInfo pathMatchInfo) {
+			this.pathRemaining = pathRemaining;
+			this.pathMatchInfo = pathMatchInfo;
+		}
+
+		/**
+		 * Return the part of a path that was not matched by a pattern.
+		 */
+		public PathContainer getPathRemaining() {
+			return this.pathRemaining;
+		}
+
+		/**
+		 * Return variables that were bound in the part of the path that was
+		 * successfully matched or an empty map.
+		 */
+		public Map<String, String> getUriVariables() {
+			return this.pathMatchInfo.getUriVariables();
+		}
+
+		/**
+		 * Return the path parameters for each bound variable.
+		 */
+		public Map<String, MultiValueMap<String, String>> getMatrixVariables() {
+			return this.pathMatchInfo.getMatrixVariables();
+		}
+	}
+
+
 	/**
 	 * Encapsulates context when attempting a match. Includes some fixed state like the
 	 * candidate currently being considered for a match but also some accumulators for
@@ -642,65 +702,4 @@ public class PathPattern implements Comparable<PathPattern> {
 			return "";
 		}
 	}
-
-	/**
-	 * Join two paths together including a separator if necessary.
-	 * Extraneous separators are removed (if the first path
-	 * ends with one and the second path starts with one).
-	 * @param path1 first path
-	 * @param path2 second path
-	 * @return joined path that may include separator if necessary
-	 */
-	private String concat(String path1, String path2) {
-		boolean path1EndsWithSeparator = (path1.charAt(path1.length() - 1) == this.separator);
-		boolean path2StartsWithSeparator = (path2.charAt(0) == this.separator);
-		if (path1EndsWithSeparator && path2StartsWithSeparator) {
-			return path1 + path2.substring(1);
-		}
-		else if (path1EndsWithSeparator || path2StartsWithSeparator) {
-			return path1 + path2;
-		}
-		else {
-			return path1 + this.separator + path2;
-		}
-	}
-
-	/**
-	 * Return if the container is not null and has more than zero elements.
-	 * @param container a path container
-	 * @return {@code true} has more than zero elements
-	 */
-	private boolean hasLength(@Nullable PathContainer container) {
-		return container != null && container.elements().size() > 0;
-	}
-
-
-	/**
-	 * Comparator that sorts patterns by specificity as follows:
-	 * <ol>
-	 * <li>Null instances are last.
-	 * <li>Catch-all patterns are last.
-	 * <li>If both patterns are catch-all, consider the length (longer wins).
-	 * <li>Compare wildcard and captured variable count (lower wins).
-	 * <li>Consider length (longer wins)
-	 * </ol>
-	 */
-	public static final Comparator<PathPattern> SPECIFICITY_COMPARATOR =
-			Comparator.nullsLast(
-					Comparator.<PathPattern>
-							comparingInt(p -> p.isCatchAll() ? 1 : 0)
-							.thenComparingInt(p -> p.isCatchAll() ? scoreByNormalizedLength(p) : 0)
-							.thenComparingInt(PathPattern::getScore)
-							.thenComparingInt(PathPattern::scoreByNormalizedLength)
-			);
-
-	private static int scoreByNormalizedLength(PathPattern pattern) {
-		return -pattern.getNormalizedLength();
-	}
-
-	private boolean pathContainerIsJustSeparator(PathContainer pathContainer) {
-		return pathContainer.value().length() == 1 &&
-				pathContainer.value().charAt(0) == separator;
-	}
-
 }