Add new constructor to JettyClientHttpConnector

This commit adds a new constructor to `JettyClientHttpConnector` and
deprecates another one. Jetty is not creating `HttpClient` instances
using a builder API, but rather setting immutable configuration at
constructor time and using setters for the rest.

This commit addresses that by deprecating the constructor variant
accepting a `Consumer` and just delegating to Spring's implementation
for setting the client resources as needed.

Closes gh-22977

Author: bclozel

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -57,25 +57,38 @@ public JettyClientHttpConnector() {
 	 * Constructor with an {@link JettyResourceFactory} that will manage shared resources.
 	 * @param resourceFactory the {@link JettyResourceFactory} to use
 	 * @param customizer the lambda used to customize the {@link HttpClient}
+	 * @deprecated in favor of {@link JettyClientHttpConnector#JettyClientHttpConnector(HttpClient, JettyResourceFactory)}
 	 */
+	@Deprecated
 	public JettyClientHttpConnector(
 			JettyResourceFactory resourceFactory, @Nullable Consumer<HttpClient> customizer) {
-
-		HttpClient httpClient = new HttpClient();
-		httpClient.setExecutor(resourceFactory.getExecutor());
-		httpClient.setByteBufferPool(resourceFactory.getByteBufferPool());
-		httpClient.setScheduler(resourceFactory.getScheduler());
+		this(new HttpClient(), resourceFactory);
 		if (customizer != null) {
-			customizer.accept(httpClient);
+			customizer.accept(this.httpClient);
 		}
-		this.httpClient = httpClient;
 	}
 
 	/**
 	 * Constructor with an initialized {@link HttpClient}.
 	 */
 	public JettyClientHttpConnector(HttpClient httpClient) {
+		this(httpClient, null);
+	}
+
+	/**
+	 * Constructor with an initialized {@link HttpClient} and configures it
+	 * with the given {@link JettyResourceFactory}.
+	 * @param httpClient the {@link HttpClient} to use
+	 * @param resourceFactory the {@link JettyResourceFactory} to use
+	 */
+	public JettyClientHttpConnector(HttpClient httpClient,
+			@Nullable JettyResourceFactory resourceFactory) {
 		Assert.notNull(httpClient, "HttpClient is required");
+		if (resourceFactory != null) {
+			httpClient.setExecutor(resourceFactory.getExecutor());
+			httpClient.setByteBufferPool(resourceFactory.getByteBufferPool());
+			httpClient.setScheduler(resourceFactory.getScheduler());
+		}
 		this.httpClient = httpClient;
 	}