Refactor HttpHeaders adapters

This commit moves all HttpHeaders to a new http.support package, hiding
them behind static methods in HeadersAdapterUtils, so that they can
be used from client and server, reactive and non-reactive.

spring-web/src/main/java/org/springframework/http/client/JettyClientHttpResponse.java

@@ -23,10 +23,10 @@
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatusCode;
-import org.springframework.util.MultiValueMap;
+import org.springframework.http.support.HeadersAdapterUtils;
 
 /**
- * {@link ClientHttpResponse} implementation based on based on Jetty's
+ * {@link ClientHttpResponse} implementation based on Jetty's
  * {@link org.eclipse.jetty.client.HttpClient}.
  *
  * @author Arjen Poutsma
@@ -45,8 +45,7 @@ public JettyClientHttpResponse(Response response, InputStream inputStream) {
 		this.response = response;
 		this.body = inputStream;
 
-		MultiValueMap<String, String> headers = new JettyHeadersAdapter(response.getHeaders());
-		this.headers = HttpHeaders.readOnlyHttpHeaders(headers);
+		this.headers = HttpHeaders.readOnlyHttpHeaders(HeadersAdapterUtils.jetty(response.getHeaders()));
 	}
 
 

spring-web/src/main/java/org/springframework/http/client/reactive/HttpComponentsClientHttpRequest.java

@@ -40,6 +40,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
+import org.springframework.http.support.HeadersAdapterUtils;
 import org.springframework.lang.Nullable;
 
 /**
@@ -158,7 +159,7 @@ protected void applyCookies() {
 
 	@Override
 	protected HttpHeaders initReadOnlyHeaders() {
-		return HttpHeaders.readOnlyHttpHeaders(new HttpComponentsHeadersAdapter(this.httpRequest));
+		return HttpHeaders.readOnlyHttpHeaders(HeadersAdapterUtils.httpComponents(this.httpRequest));
 	}
 
 	public AsyncRequestProducer toRequestProducer() {

spring-web/src/main/java/org/springframework/http/client/reactive/HttpComponentsClientHttpResponse.java

@@ -31,6 +31,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.http.ResponseCookie;
+import org.springframework.http.support.HeadersAdapterUtils;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 
@@ -62,8 +63,7 @@ public HttpComponentsClientHttpResponse(DataBufferFactory dataBufferFactory,
 		this.message = message;
 		this.context = context;
 
-		MultiValueMap<String, String> adapter = new HttpComponentsHeadersAdapter(message.getHead());
-		this.headers = HttpHeaders.readOnlyHttpHeaders(adapter);
+		this.headers = HttpHeaders.readOnlyHttpHeaders(HeadersAdapterUtils.httpComponents(message.getHead()));
 	}
 
 

spring-web/src/main/java/org/springframework/http/client/reactive/JettyClientHttpRequest.java

@@ -37,7 +37,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
-import org.springframework.http.client.JettyHeadersAdapter;
+import org.springframework.http.support.HeadersAdapterUtils;
 
 /**
  * {@link ClientHttpRequest} implementation for the Jetty ReactiveStreams HTTP client.
@@ -147,7 +147,7 @@ protected void applyHeaders() {
 
 	@Override
 	protected HttpHeaders initReadOnlyHeaders() {
-		return HttpHeaders.readOnlyHttpHeaders(new JettyHeadersAdapter(this.jettyRequest.getHeaders()));
+		return HttpHeaders.readOnlyHttpHeaders(HeadersAdapterUtils.jetty(this.jettyRequest.getHeaders()));
 	}
 
 	public ReactiveRequest toReactiveRequest() {

spring-web/src/main/java/org/springframework/http/client/reactive/JettyClientHttpResponse.java

@@ -29,7 +29,7 @@
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.http.ResponseCookie;
-import org.springframework.http.client.JettyHeadersAdapter;
+import org.springframework.http.support.HeadersAdapterUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.LinkedMultiValueMap;
@@ -59,8 +59,7 @@ public JettyClientHttpResponse(ReactiveResponse reactiveResponse, Publisher<Data
 		this.reactiveResponse = reactiveResponse;
 		this.content = Flux.from(content);
 
-		MultiValueMap<String, String> headers = new JettyHeadersAdapter(reactiveResponse.getHeaders());
-		this.headers = HttpHeaders.readOnlyHttpHeaders(headers);
+		this.headers = HttpHeaders.readOnlyHttpHeaders(HeadersAdapterUtils.jetty(reactiveResponse.getHeaders()));
 	}