Support convention based @ImportHttpServices imports

Update `@ImportHttpServices` to support convention based imports when
neither types or base packages are specified. This update allows
`@ImportHttpServices` to work in a similar way to `@ComponentScan`
where the annotation alone is enough to find HTTP interface clients.

For example:

	package com.example;

	@configuration
	@ImportHttpServices(group = "test")
	static class MyConfig {
		// this config scans for interface clients in `com.example`
	}

See gh-35447

Author: philwebb

spring-web/src/main/java/org/springframework/web/service/registry/ImportHttpServiceRegistrar.java

@@ -18,6 +18,8 @@
 
 import org.springframework.core.annotation.MergedAnnotation;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ObjectUtils;
 
 /**
  * Built-in implementation of {@link AbstractHttpServiceRegistrar} that uses
@@ -37,23 +39,31 @@ protected void registerHttpServices(GroupRegistry registry, AnnotationMetadata m
 		MergedAnnotation<?> groupsAnnot = metadata.getAnnotations().get(ImportHttpServices.Container.class);
 		if (groupsAnnot.isPresent()) {
 			for (MergedAnnotation<?> annot : groupsAnnot.getAnnotationArray("value", ImportHttpServices.class)) {
-				processImportAnnotation(annot, registry);
+				processImportAnnotation(annot, registry, metadata);
 			}
 		}
 
 		metadata.getAnnotations().stream(ImportHttpServices.class)
-				.forEach(annot -> processImportAnnotation(annot, registry));
+				.forEach(annot -> processImportAnnotation(annot, registry, metadata));
 	}
 
-	private void processImportAnnotation(MergedAnnotation<?> annotation, GroupRegistry groupRegistry) {
+	private void processImportAnnotation(MergedAnnotation<?> annotation, GroupRegistry groupRegistry,
+			AnnotationMetadata metadata) {
 
 		String groupName = annotation.getString("group");
 		HttpServiceGroup.ClientType clientType = annotation.getEnum("clientType", HttpServiceGroup.ClientType.class);
+		Class<?>[] types = annotation.getClassArray("types");
+		Class<?>[] basePackageClasses = annotation.getClassArray("basePackageClasses");
+		String[] basePackages = annotation.getStringArray("basePackages");
+
+		if (ObjectUtils.isEmpty(types) && ObjectUtils.isEmpty(basePackages) && ObjectUtils.isEmpty(basePackageClasses)) {
+			basePackages = new String[] { ClassUtils.getPackageName(metadata.getClassName()) };
+		}
 
 		groupRegistry.forGroup(groupName, clientType)
-				.register(annotation.getClassArray("types"))
-				.detectInBasePackages(annotation.getStringArray("basePackages"))
-				.detectInBasePackages(annotation.getClassArray("basePackageClasses"));
+				.register(types)
+				.detectInBasePackages(basePackageClasses)
+				.detectInBasePackages(basePackages);
 	}
 
 }

spring-web/src/main/java/org/springframework/web/service/registry/ImportHttpServices.java

@@ -39,6 +39,8 @@
  *
  * <p>The HTTP Services for each group can be listed via {@link #types()}, or
  * detected via {@link #basePackageClasses()} or {@link #basePackages()}.
+ * If neither types or base packages are defined, detection will occur recursively
+ * beginning with the package of the class that declares this annotation.
  *
  * <p>An application can autowire HTTP Service proxy beans, or autowire the
  * {@link HttpServiceProxyRegistry} from which to obtain proxies.

spring-web/src/test/java/org/springframework/web/service/registry/ImportHttpServiceRegistrarTests.java

@@ -33,6 +33,7 @@
 import org.springframework.web.service.registry.HttpServiceGroup.ClientType;
 import org.springframework.web.service.registry.echo.EchoA;
 import org.springframework.web.service.registry.echo.EchoB;
+import org.springframework.web.service.registry.echo.ScanConventionConfig;
 import org.springframework.web.service.registry.greeting.GreetingA;
 import org.springframework.web.service.registry.greeting.GreetingB;
 
@@ -83,6 +84,12 @@ void basicScan() {
 				TestGroup.ofPackageClasses(GREETING_GROUP, GreetingA.class));
 	}
 
+	@Test
+	void basicScanByConvention() {
+		doRegister(ScanConventionConfig.class);
+		assertGroups(TestGroup.ofPackageNames(ECHO_GROUP, ClientType.UNSPECIFIED, EchoA.class.getPackage().getName()));
+	}
+
 	@Test
 	@CompileWithForkedClassLoader
 	void basicScanWithAot() {

spring-web/src/test/java/org/springframework/web/service/registry/TestGroup.java

@@ -53,4 +53,10 @@ public static TestGroup ofPackageClasses(String name, ClientType clientType, Cla
 		return group;
 	}
 
+	public static TestGroup ofPackageNames(String name, ClientType clientType, String... packageNames) {
+		TestGroup group = new TestGroup(name, clientType);
+		group.packageNames().addAll(Arrays.asList(packageNames));
+		return group;
+	}
+
 }

spring-web/src/test/java/org/springframework/web/service/registry/echo/ScanConventionConfig.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2002-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.service.registry.echo;
+
+import org.springframework.web.service.registry.ImportHttpServices;
+
+@ImportHttpServices(group = "echo")
+public class ScanConventionConfig {
+
+}