Add HttpServiceProxyFactory builder

See gh-28386

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceProxyFactory.java

@@ -18,9 +18,11 @@
 
 import java.lang.reflect.Method;
 import java.time.Duration;
-import java.util.HashMap;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
@@ -29,62 +31,167 @@
 import org.springframework.core.MethodIntrospector;
 import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.core.convert.ConversionService;
+import org.springframework.format.support.DefaultFormattingConversionService;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.web.service.annotation.HttpExchange;
 
 
 /**
- * Factory to create a proxy for an HTTP service with {@link HttpExchange} methods.
+ * Factory for creating a client proxy given an HTTP service interface with
+ * {@link HttpExchange @HttpExchange} methods.
  *
  * @author Rossen Stoyanchev
  * @since 6.0
  */
-public class HttpServiceProxyFactory {
-
-	private final List<HttpServiceArgumentResolver> argumentResolvers;
+public final class HttpServiceProxyFactory {
 
 	private final HttpClientAdapter clientAdapter;
 
+	private final List<HttpServiceArgumentResolver> argumentResolvers;
+
 	private final ReactiveAdapterRegistry reactiveAdapterRegistry;
 
 	private final Duration blockTimeout;
 
 
-	public HttpServiceProxyFactory(
-			List<HttpServiceArgumentResolver> argumentResolvers, HttpClientAdapter clientAdapter,
+	private HttpServiceProxyFactory(
+			HttpClientAdapter clientAdapter, List<HttpServiceArgumentResolver> argumentResolvers,
 			ReactiveAdapterRegistry reactiveAdapterRegistry, Duration blockTimeout) {
 
-		this.argumentResolvers = argumentResolvers;
 		this.clientAdapter = clientAdapter;
+		this.argumentResolvers = argumentResolvers;
 		this.reactiveAdapterRegistry = reactiveAdapterRegistry;
 		this.blockTimeout = blockTimeout;
 	}
 
 
 	/**
-	 * Create a proxy for executing requests to the given HTTP service.
+	 * Return a proxy that implements the given HTTP service interface to perform
+	 * HTTP requests and retrieves responses through an HTTP client.
 	 * @param serviceType the HTTP service to create a proxy for
-	 * @param <S> the service type
+	 * @param <S> the HTTP service type
 	 * @return the created proxy
 	 */
 	public <S> S createClient(Class<S> serviceType) {
 
 		List<HttpServiceMethod> methods =
-				MethodIntrospector.selectMethods(serviceType, this::isHttpRequestMethod)
+				MethodIntrospector.selectMethods(serviceType, this::isExchangeMethod)
 						.stream()
-						.map(method -> initServiceMethod(method, serviceType))
+						.map(method ->
+								new HttpServiceMethod(
+										method, serviceType, this.argumentResolvers,
+										this.clientAdapter, this.reactiveAdapterRegistry, this.blockTimeout))
 						.toList();
 
 		return ProxyFactory.getProxy(serviceType, new HttpServiceMethodInterceptor(methods));
 	}
 
-	private boolean isHttpRequestMethod(Method method) {
+	private boolean isExchangeMethod(Method method) {
 		return AnnotatedElementUtils.hasAnnotation(method, HttpExchange.class);
 	}
 
-	private HttpServiceMethod initServiceMethod(Method method, Class<?> serviceType) {
-		return new HttpServiceMethod(
-				method, serviceType, this.argumentResolvers,
-				this.clientAdapter, this.reactiveAdapterRegistry, this.blockTimeout);
+
+	/**
+	 * Return a builder for an {@link HttpServiceProxyFactory}.
+	 * @param adapter an adapter for the underlying HTTP client
+	 * @return the builder
+	 */
+	public static Builder builder(HttpClientAdapter adapter) {
+		return new Builder(adapter);
+	}
+
+
+	/**
+	 * Builder for {@link HttpServiceProxyFactory}.
+	 */
+	public final static class Builder {
+
+		private final HttpClientAdapter clientAdapter;
+
+		private final List<HttpServiceArgumentResolver> customResolvers = new ArrayList<>();
+
+		@Nullable
+		private ConversionService conversionService;
+
+		private ReactiveAdapterRegistry reactiveAdapterRegistry = ReactiveAdapterRegistry.getSharedInstance();
+
+		private Duration blockTimeout = Duration.ofSeconds(5);
+
+		private Builder(HttpClientAdapter clientAdapter) {
+			Assert.notNull(clientAdapter, "HttpClientAdapter is required");
+			this.clientAdapter = clientAdapter;
+		}
+
+		/**
+		 * Register a custom argument resolver. This will be inserted ahead of
+		 * default resolvers.
+		 * @return the same builder instance
+		 */
+		public Builder addCustomResolver(HttpServiceArgumentResolver resolver) {
+			this.customResolvers.add(resolver);
+			return this;
+		}
+
+		/**
+		 * Set the {@link ConversionService} to use where input values need to
+		 * be formatted as Strings.
+		 * <p>By default this is {@link DefaultFormattingConversionService}.
+		 * @return the same builder instance
+		 */
+		public Builder setConversionService(ConversionService conversionService) {
+			this.conversionService = conversionService;
+			return this;
+		}
+
+		/**
+		 * Set the {@link ReactiveAdapterRegistry} to use to support different
+		 * asynchronous types for HTTP Service method return values.
+		 * <p>By default this is {@link ReactiveAdapterRegistry#getSharedInstance()}.
+		 * @return the same builder instance
+		 */
+		public Builder setReactiveAdapterRegistry(ReactiveAdapterRegistry registry) {
+			this.reactiveAdapterRegistry = registry;
+			return this;
+		}
+
+		/**
+		 * Configure how long to wait for a response for an HTTP Service method
+		 * with a synchronous (blocking) method signature.
+		 * <p>By default this is 5 seconds.
+		 * @param blockTimeout the timeout value
+		 * @return the same builder instance
+		 */
+		public Builder setBlockTimeout(Duration blockTimeout) {
+			this.blockTimeout = blockTimeout;
+			return this;
+		}
+
+		/**
+		 * Build and return the {@link HttpServiceProxyFactory} instance.
+		 */
+		public HttpServiceProxyFactory build() {
+
+			ConversionService conversionService = initConversionService();
+			List<HttpServiceArgumentResolver> resolvers = initArgumentResolvers(conversionService);
+
+			return new HttpServiceProxyFactory(
+					this.clientAdapter, resolvers, this.reactiveAdapterRegistry, this.blockTimeout);
+		}
+
+		private ConversionService initConversionService() {
+			return (this.conversionService != null ?
+					this.conversionService : new DefaultFormattingConversionService());
+		}
+
+		private List<HttpServiceArgumentResolver> initArgumentResolvers(ConversionService conversionService) {
+			List<HttpServiceArgumentResolver> resolvers = new ArrayList<>(this.customResolvers);
+			resolvers.add(new HttpMethodArgumentResolver());
+			resolvers.add(new PathVariableArgumentResolver(conversionService));
+			return resolvers;
+		}
+
 	}
 
 
@@ -93,10 +200,11 @@ private HttpServiceMethod initServiceMethod(Method method, Class<?> serviceType)
 	 */
 	private static final class HttpServiceMethodInterceptor implements MethodInterceptor {
 
-		private final Map<Method, HttpServiceMethod> httpServiceMethods = new HashMap<>();
+		private final Map<Method, HttpServiceMethod> httpServiceMethods;
 
 		private HttpServiceMethodInterceptor(List<HttpServiceMethod> methods) {
-			methods.forEach(serviceMethod -> this.httpServiceMethods.put(serviceMethod.getMethod(), serviceMethod));
+			this.httpServiceMethods = methods.stream()
+					.collect(Collectors.toMap(HttpServiceMethod::getMethod, Function.identity()));
 		}
 
 		@Override
@@ -105,7 +213,6 @@ public Object invoke(MethodInvocation invocation) {
 			HttpServiceMethod httpServiceMethod = this.httpServiceMethods.get(method);
 			return httpServiceMethod.invoke(invocation.getArguments());
 		}
-
 	}
 
 }

spring-web/src/test/java/org/springframework/web/service/invoker/HttpMethodArgumentResolverTests.java

@@ -34,7 +34,7 @@ public class HttpMethodArgumentResolverTests {
 
 	private final TestHttpClientAdapter clientAdapter = new TestHttpClientAdapter();
 
-	private final Service service = this.clientAdapter.createService(Service.class, new HttpMethodArgumentResolver());
+	private final Service service = this.clientAdapter.createService(Service.class);
 
 
 	@Test

spring-web/src/test/java/org/springframework/web/service/invoker/PathVariableArgumentResolverTests.java

@@ -21,7 +21,6 @@
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.lang.Nullable;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.service.annotation.GetExchange;
@@ -39,8 +38,7 @@ class PathVariableArgumentResolverTests {
 
 	private final TestHttpClientAdapter clientAdapter = new TestHttpClientAdapter();
 
-	private final Service service = this.clientAdapter.createService(
-			Service.class, new PathVariableArgumentResolver(new DefaultConversionService()));
+	private final Service service = this.clientAdapter.createService(Service.class);
 
 
 	@Test

spring-web/src/test/java/org/springframework/web/service/invoker/TestHttpClientAdapter.java

@@ -16,14 +16,10 @@
 
 package org.springframework.web.service.invoker;
 
-import java.time.Duration;
-import java.util.Arrays;
-
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.ParameterizedTypeReference;
-import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.ResponseEntity;
 import org.springframework.lang.Nullable;
@@ -53,11 +49,8 @@ class TestHttpClientAdapter implements HttpClientAdapter {
 	/**
 	 * Create the proxy for the give service type.
 	 */
-	public <S> S createService(Class<S> serviceType, HttpServiceArgumentResolver... resolvers) {
-
-		HttpServiceProxyFactory factory = new HttpServiceProxyFactory(
-				Arrays.asList(resolvers), this, ReactiveAdapterRegistry.getSharedInstance(), Duration.ofSeconds(5));
-
+	public <S> S createService(Class<S> serviceType) {
+		HttpServiceProxyFactory factory = HttpServiceProxyFactory.builder(this).build();
 		return factory.createClient(serviceType);
 	}
 

spring-webflux/src/test/java/org/springframework/web/reactive/function/client/support/WebClientHttpServiceProxyTests.java

@@ -19,7 +19,6 @@
 
 import java.io.IOException;
 import java.time.Duration;
-import java.util.Collections;
 import java.util.function.Consumer;
 
 import okhttp3.mockwebserver.MockResponse;
@@ -30,7 +29,6 @@
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
-import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.http.client.reactive.ReactorClientHttpConnector;
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.service.annotation.GetExchange;
@@ -59,11 +57,8 @@ void setUp() {
 				.baseUrl(this.server.url("/").toString())
 				.build();
 
-		WebClientAdapter webClientAdapter = new WebClientAdapter(webClient);
-
-		HttpServiceProxyFactory proxyFactory = new HttpServiceProxyFactory(
-				Collections.emptyList(), webClientAdapter, ReactiveAdapterRegistry.getSharedInstance(),
-				Duration.ofSeconds(5));
+		WebClientAdapter clientAdapter = new WebClientAdapter(webClient);
+		HttpServiceProxyFactory proxyFactory = HttpServiceProxyFactory.builder(clientAdapter).build();
 
 		this.httpService = proxyFactory.createClient(TestHttpService.class);
 	}