diff --git a/spring-cloud-openfeign-core/pom.xml b/spring-cloud-openfeign-core/pom.xml
index 1f590c46..a063e212 100644
--- a/spring-cloud-openfeign-core/pom.xml
+++ b/spring-cloud-openfeign-core/pom.xml
@@ -220,6 +220,12 @@
3.4.0
test
+
+ io.vavr
+ vavr
+ 0.10.0
+ test
+
diff --git a/spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringMvcContract.java b/spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringMvcContract.java
index 3c7761cf..87ab9ce7 100644
--- a/spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringMvcContract.java
+++ b/spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringMvcContract.java
@@ -45,6 +45,7 @@ import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.MethodParameter;
import org.springframework.core.ParameterNameDiscoverer;
+import org.springframework.core.ResolvableType;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.TypeDescriptor;
@@ -129,8 +130,8 @@ public class SpringMvcContract extends Contract.BaseContract
// Feign applies the Param.Expander to each element of an Iterable, so in those
// cases we need to provide a TypeDescriptor of the element.
if (typeDescriptor.isAssignableTo(ITERABLE_TYPE_DESCRIPTOR)) {
- TypeDescriptor elementTypeDescriptor = typeDescriptor
- .getElementTypeDescriptor();
+ TypeDescriptor elementTypeDescriptor = getElementTypeDescriptor(
+ typeDescriptor);
checkState(elementTypeDescriptor != null,
"Could not resolve element type of Iterable type %s. Not declared?",
@@ -141,6 +142,22 @@ public class SpringMvcContract extends Contract.BaseContract
return typeDescriptor;
}
+ private static TypeDescriptor getElementTypeDescriptor(
+ TypeDescriptor typeDescriptor) {
+ TypeDescriptor elementTypeDescriptor = typeDescriptor.getElementTypeDescriptor();
+ // that means it's not a collection but it is iterable, gh-135
+ if (elementTypeDescriptor == null
+ && Iterable.class.isAssignableFrom(typeDescriptor.getType())) {
+ ResolvableType type = typeDescriptor.getResolvableType().as(Iterable.class)
+ .getGeneric(0);
+ if (type.resolve() == null) {
+ return null;
+ }
+ return new TypeDescriptor(type, null, typeDescriptor.getAnnotations());
+ }
+ return elementTypeDescriptor;
+ }
+
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
diff --git a/spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/valid/IterableParameterTests.java b/spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/valid/IterableParameterTests.java
new file mode 100644
index 00000000..c298c8ce
--- /dev/null
+++ b/spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/valid/IterableParameterTests.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2013-2019 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.
+ * You may obtain a copy of the License at
+ *
+ * http://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.cloud.openfeign.valid;
+
+import com.netflix.loadbalancer.Server;
+import com.netflix.loadbalancer.ServerList;
+import io.vavr.collection.HashSet;
+import io.vavr.collection.Set;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.cloud.netflix.ribbon.RibbonClient;
+import org.springframework.cloud.netflix.ribbon.StaticServerList;
+import org.springframework.cloud.openfeign.EnableFeignClients;
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.cloud.openfeign.test.NoSecurityConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Spencer Gibb
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringBootTest(classes = IterableParameterTests.Application.class, webEnvironment = WebEnvironment.RANDOM_PORT, value = {
+ "spring.application.name=iterableparametertest",
+ "logging.level.org.springframework.cloud.openfeign.valid=DEBUG",
+ "feign.httpclient.enabled=false", "feign.okhttp.enabled=false",
+ "feign.hystrix.enabled=false" })
+@DirtiesContext
+public class IterableParameterTests {
+
+ @Autowired
+ private TestClient testClient;
+
+ @Test
+ public void testClient() {
+ assertThat(this.testClient).as("testClient was null").isNotNull();
+ String results = this.testClient.echo(HashSet.of("a", "b"));
+ assertThat(results).isEqualTo("a,b");
+ }
+
+ @FeignClient(name = "localapp")
+ protected interface TestClient {
+
+ @GetMapping("/echo")
+ String echo(@RequestParam Set set);
+
+ }
+
+ @Configuration
+ @EnableAutoConfiguration
+ @RestController
+ @EnableFeignClients(clients = TestClient.class)
+ @RibbonClient(name = "localapp", configuration = LocalRibbonClientConfiguration.class)
+ @Import(NoSecurityConfiguration.class)
+ protected static class Application {
+
+ @GetMapping("/echo")
+ public String echo(@RequestParam String set) {
+ return set;
+ }
+
+ }
+
+ // Load balancer with fixed server list for "local" pointing to localhost
+ public static class LocalRibbonClientConfiguration {
+
+ @LocalServerPort
+ private int port = 0;
+
+ @Bean
+ public ServerList ribbonServerList() {
+ return new StaticServerList<>(new Server("localhost", this.port));
+ }
+
+ }
+
+}
diff --git a/src/checkstyle/checkstyle-suppressions.xml b/src/checkstyle/checkstyle-suppressions.xml
index 2bd6edec..e0aac3a4 100644
--- a/src/checkstyle/checkstyle-suppressions.xml
+++ b/src/checkstyle/checkstyle-suppressions.xml
@@ -9,6 +9,7 @@
+