Fine-tuned assertions and related polishing

Author: jhoeller

Diff for: spring-expression/src/main/java/org/springframework/expression/spel/standard/Tokenizer.java

@@ -265,7 +265,7 @@ else if (isTwoCharToken(TokenKind.SAFE_NAVI)) {
 						raiseParseException(this.pos, SpelMessage.UNEXPECTED_ESCAPE_CHAR);
 						break;
 					default:
-						throw new IllegalStateException("Cannot handle ('" + ch + "')");
+						throw new IllegalStateException("Cannot handle (" + (int) ch + ") '" + ch + "'");
 				}
 			}
 		}

Diff for: spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -414,7 +414,6 @@ public HttpHeaders() {
 	 * Private constructor that can create read-only {@code HttpHeader} instances.
 	 */
 	private HttpHeaders(Map<String, List<String>> headers, boolean readOnly) {
-		Assert.notNull(headers, "'headers' must not be null");
 		if (readOnly) {
 			Map<String, List<String>> map = new LinkedCaseInsensitiveMap<>(headers.size(), Locale.ENGLISH);
 			headers.forEach((key, valueList) -> map.put(key, Collections.unmodifiableList(valueList)));
@@ -1556,6 +1555,7 @@ public String toString() {
 	 * Return a {@code HttpHeaders} object that can only be read, not written to.
 	 */
 	public static HttpHeaders readOnlyHttpHeaders(HttpHeaders headers) {
+		Assert.notNull(headers, "HttpHeaders must not be null");
 		return (headers.readOnly ? headers : new HttpHeaders(headers, true));
 	}
 

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/client/ClientRequest.java

@@ -114,7 +114,7 @@ static Builder from(ClientRequest other) {
 	/**
 	 * Create a builder with the given method and url.
 	 * @param method the HTTP method (GET, POST, etc)
-	 * @param url the URL
+	 * @param url the url (as a URI instance)
 	 * @return the created builder
 	 * @deprecated in favor of {@link #create(HttpMethod, URI)}
 	 */
@@ -126,7 +126,7 @@ static Builder method(HttpMethod method, URI url) {
 	/**
 	 * Create a request builder with the given method and url.
 	 * @param method the HTTP method (GET, POST, etc)
-	 * @param url the URL
+	 * @param url the url (as a URI instance)
 	 * @return the created builder
 	 */
 	static Builder create(HttpMethod method, URI url) {

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultClientRequestBuilder.java

@@ -49,28 +49,30 @@
  */
 final class DefaultClientRequestBuilder implements ClientRequest.Builder {
 
+	private HttpMethod method;
+
+	private URI url;
+
 	private final HttpHeaders headers = new HttpHeaders();
 
 	private final MultiValueMap<String, String> cookies = new LinkedMultiValueMap<>();
 
 	private final Map<String, Object> attributes = new LinkedHashMap<>();
 
-	private HttpMethod method;
-
-	private URI url;
-
-	private BodyInserter<?, ? super ClientHttpRequest> inserter = BodyInserters.empty();
+	private BodyInserter<?, ? super ClientHttpRequest> body = BodyInserters.empty();
 
 
 	public DefaultClientRequestBuilder(HttpMethod method, URI url) {
-		method(method);
-		url(url);
+		Assert.notNull(method, "HttpMethod must not be null");
+		Assert.notNull(url, "URI must not be null");
+		this.method = method;
+		this.url = url;
 	}
 
 	public DefaultClientRequestBuilder(ClientRequest other) {
 		Assert.notNull(other, "ClientRequest must not be null");
-		method(other.method());
-		url(other.url());
+		this.method = other.method();
+		this.url = other.url();
 		headers(headers -> headers.addAll(other.headers()));
 		cookies(cookies -> cookies.addAll(other.cookies()));
 		attributes(attributes -> attributes.putAll(other.attributes()));
@@ -125,7 +127,7 @@ public <S, P extends Publisher<S>> ClientRequest.Builder body(P publisher, Class
 		Assert.notNull(publisher, "'publisher' must not be null");
 		Assert.notNull(elementClass, "'elementClass' must not be null");
 
-		this.inserter = BodyInserters.fromPublisher(publisher, elementClass);
+		this.body = BodyInserters.fromPublisher(publisher, elementClass);
 		return this;
 	}
 
@@ -136,7 +138,7 @@ public <S, P extends Publisher<S>> ClientRequest.Builder body(
 		Assert.notNull(publisher, "'publisher' must not be null");
 		Assert.notNull(typeReference, "'typeReference' must not be null");
 
-		this.inserter = BodyInserters.fromPublisher(publisher, typeReference);
+		this.body = BodyInserters.fromPublisher(publisher, typeReference);
 		return this;
 	}
 
@@ -154,14 +156,13 @@ public ClientRequest.Builder attributes(Consumer<Map<String, Object>> attributes
 
 	@Override
 	public ClientRequest.Builder body(BodyInserter<?, ? super ClientHttpRequest> inserter) {
-		this.inserter = inserter;
+		this.body = inserter;
 		return this;
 	}
 
 	@Override
 	public ClientRequest build() {
-		return new BodyInserterRequest(this.method, this.url, this.headers, this.cookies,
-				this.inserter, this.attributes);
+		return new BodyInserterRequest(this.method, this.url, this.headers, this.cookies, this.body, this.attributes);
 	}
 
 
@@ -175,20 +176,19 @@ private static class BodyInserterRequest implements ClientRequest {
 
 		private final MultiValueMap<String, String> cookies;
 
-		private final BodyInserter<?, ? super ClientHttpRequest> inserter;
+		private final BodyInserter<?, ? super ClientHttpRequest> body;
 
 		private final Map<String, Object> attributes;
 
 		public BodyInserterRequest(HttpMethod method, URI url, HttpHeaders headers,
-				MultiValueMap<String, String> cookies,
-				BodyInserter<?, ? super ClientHttpRequest> inserter,
+				MultiValueMap<String, String> cookies, BodyInserter<?, ? super ClientHttpRequest> body,
 				Map<String, Object> attributes) {
 
 			this.method = method;
 			this.url = url;
 			this.headers = HttpHeaders.readOnlyHttpHeaders(headers);
 			this.cookies = CollectionUtils.unmodifiableMultiValueMap(cookies);
-			this.inserter = inserter;
+			this.body = body;
 			this.attributes = Collections.unmodifiableMap(attributes);
 		}
 
@@ -214,7 +214,7 @@ public MultiValueMap<String, String> cookies() {
 
 		@Override
 		public BodyInserter<?, ? super ClientHttpRequest> body() {
-			return this.inserter;
+			return this.body;
 		}
 
 		@Override
@@ -240,17 +240,15 @@ public Mono<Void> writeTo(ClientHttpRequest request, ExchangeStrategies strategi
 				}));
 			}
 
-			return this.inserter.insert(request, new BodyInserter.Context() {
+			return this.body.insert(request, new BodyInserter.Context() {
 				@Override
 				public List<HttpMessageWriter<?>> messageWriters() {
 					return strategies.messageWriters();
 				}
-
 				@Override
 				public Optional<ServerHttpRequest> serverRequest() {
 					return Optional.empty();
 				}
-
 				@Override
 				public Map<String, Object> hints() {
 					return Collections.emptyMap();

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultClientResponseBuilder.java

@@ -42,16 +42,16 @@
  */
 final class DefaultClientResponseBuilder implements ClientResponse.Builder {
 
+	private ExchangeStrategies strategies;
+
+	private HttpStatus statusCode = HttpStatus.OK;
+
 	private final HttpHeaders headers = new HttpHeaders();
 
 	private final MultiValueMap<String, ResponseCookie> cookies = new LinkedMultiValueMap<>();
 
-	private HttpStatus statusCode = HttpStatus.OK;
-
 	private Flux<DataBuffer> body = Flux.empty();
 
-	private ExchangeStrategies strategies;
-
 
 	public DefaultClientResponseBuilder(ExchangeStrategies strategies) {
 		Assert.notNull(strategies, "ExchangeStrategies must not be null");
@@ -84,7 +84,6 @@ public ClientResponse.Builder header(String headerName, String... headerValues)
 
 	@Override
 	public ClientResponse.Builder headers(Consumer<HttpHeaders> headersConsumer) {
-		Assert.notNull(headersConsumer, "Consumer must not be null");
 		headersConsumer.accept(this.headers);
 		return this;
 	}
@@ -99,7 +98,6 @@ public DefaultClientResponseBuilder cookie(String name, String... values) {
 
 	@Override
 	public ClientResponse.Builder cookies(Consumer<MultiValueMap<String, ResponseCookie>> cookiesConsumer) {
-		Assert.notNull(cookiesConsumer, "Consumer must not be null");
 		cookiesConsumer.accept(this.cookies);
 		return this;
 	}

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java

@@ -208,9 +208,7 @@ public WebClient build() {
 
 	private static @Nullable HttpHeaders unmodifiableCopy(@Nullable HttpHeaders original) {
 		if (original != null) {
-			HttpHeaders copy = new HttpHeaders();
-			copy.putAll(original);
-			return HttpHeaders.readOnlyHttpHeaders(copy);
+			return HttpHeaders.readOnlyHttpHeaders(original);
 		}
 		else {
 			return null;

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultEntityResponseBuilder.java

@@ -96,7 +96,6 @@ public EntityResponse.Builder<T> cookie(ResponseCookie cookie) {
 
 	@Override
 	public EntityResponse.Builder<T> cookies(Consumer<MultiValueMap<String, ResponseCookie>> cookiesConsumer) {
-		Assert.notNull(cookiesConsumer, "Consumer must not be null");
 		cookiesConsumer.accept(this.cookies);
 		return this;
 	}

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultRenderingResponseBuilder.java

@@ -99,7 +99,6 @@ public RenderingResponse.Builder cookie(ResponseCookie cookie) {
 
 	@Override
 	public RenderingResponse.Builder cookies(Consumer<MultiValueMap<String, ResponseCookie>> cookiesConsumer) {
-		Assert.notNull(cookiesConsumer, "Consumer must not be null");
 		cookiesConsumer.accept(this.cookies);
 		return this;
 	}

Diff for: spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultServerRequest.java

@@ -76,14 +76,10 @@ class DefaultServerRequest implements ServerRequest {
 
 	DefaultServerRequest(ServerWebExchange exchange, List<HttpMessageReader<?>> messageReaders) {
 		this.exchange = exchange;
-		this.messageReaders = unmodifiableCopy(messageReaders);
+		this.messageReaders = Collections.unmodifiableList(new ArrayList<>(messageReaders));
 		this.headers = new DefaultHeaders();
 	}
 
-	private static <T> List<T> unmodifiableCopy(List<? extends T> list) {
-		return Collections.unmodifiableList(new ArrayList<>(list));
-	}
-
 
 	@Override
 	public String methodName() {