From f93cb2f539e9fa7b371dfec05a45c91b423d6a96 Mon Sep 17 00:00:00 2001
From: Brian Clozel <bclozel@pivotal.io>
Date: Thu, 25 Aug 2016 17:14:09 +0200
Subject: [PATCH] Support ordered interceptors in RestTemplate

This commit sorts `ClientHttpRequestInterceptor`s when those are set in
`InterceptingHttpAccessor` (which `RestTemplate` extends from).

Interceptors can now be annotated with `@Order` or implements `Ordered`
to reflect their order of execution for each request.

Issue: SPR-13971
---
 .../support/InterceptingHttpAccessor.java     |  2 +
 .../InterceptingHttpAccessorTests.java        | 91 +++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 spring-web/src/test/java/org/springframework/http/client/support/InterceptingHttpAccessorTests.java

diff --git a/spring-web/src/main/java/org/springframework/http/client/support/InterceptingHttpAccessor.java b/spring-web/src/main/java/org/springframework/http/client/support/InterceptingHttpAccessor.java
index 704b421bd2e..ecb28598a3b 100644
--- a/spring-web/src/main/java/org/springframework/http/client/support/InterceptingHttpAccessor.java
+++ b/spring-web/src/main/java/org/springframework/http/client/support/InterceptingHttpAccessor.java
@@ -19,6 +19,7 @@ package org.springframework.http.client.support;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.ClientHttpRequestInterceptor;
 import org.springframework.http.client.InterceptingClientHttpRequestFactory;
@@ -40,6 +41,7 @@ public abstract class InterceptingHttpAccessor extends HttpAccessor {
 	 * Sets the request interceptors that this accessor should use.
 	 */
 	public void setInterceptors(List<ClientHttpRequestInterceptor> interceptors) {
+		AnnotationAwareOrderComparator.sort(interceptors);
 		this.interceptors = interceptors;
 	}
 
diff --git a/spring-web/src/test/java/org/springframework/http/client/support/InterceptingHttpAccessorTests.java b/spring-web/src/test/java/org/springframework/http/client/support/InterceptingHttpAccessorTests.java
new file mode 100644
index 00000000000..0e515883a31
--- /dev/null
+++ b/spring-web/src/test/java/org/springframework/http/client/support/InterceptingHttpAccessorTests.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2002-2016 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.http.client.support;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
+import org.springframework.http.HttpRequest;
+import org.springframework.http.client.ClientHttpRequestExecution;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.http.client.ClientHttpResponse;
+
+/**
+ * Tests for {@link InterceptingHttpAccessor}.
+ *
+ * @author Brian Clozel
+ */
+public class InterceptingHttpAccessorTests {
+
+	@Test
+	public void getInterceptors() throws Exception {
+		TestInterceptingHttpAccessor accessor = new TestInterceptingHttpAccessor();
+		List<ClientHttpRequestInterceptor> interceptors = Arrays.asList(
+				new SecondClientHttpRequestInterceptor(),
+				new ThirdClientHttpRequestInterceptor(),
+				new FirstClientHttpRequestInterceptor()
+
+		);
+		accessor.setInterceptors(interceptors);
+
+		assertThat(accessor.getInterceptors().get(0), Matchers.instanceOf(FirstClientHttpRequestInterceptor.class));
+		assertThat(accessor.getInterceptors().get(1), Matchers.instanceOf(SecondClientHttpRequestInterceptor.class));
+		assertThat(accessor.getInterceptors().get(2), Matchers.instanceOf(ThirdClientHttpRequestInterceptor.class));
+	}
+
+	private class TestInterceptingHttpAccessor extends InterceptingHttpAccessor {
+	}
+
+	@Order(1)
+	private class FirstClientHttpRequestInterceptor implements ClientHttpRequestInterceptor {
+		@Override
+		public ClientHttpResponse intercept(HttpRequest request, byte[] body,
+				ClientHttpRequestExecution execution) throws IOException {
+			return null;
+		}
+	}
+
+	private class SecondClientHttpRequestInterceptor implements ClientHttpRequestInterceptor, Ordered {
+		@Override
+		public ClientHttpResponse intercept(HttpRequest request, byte[] body,
+				ClientHttpRequestExecution execution) throws IOException {
+			return null;
+		}
+
+		@Override
+		public int getOrder() {
+			return 2;
+		}
+	}
+
+	private class ThirdClientHttpRequestInterceptor implements ClientHttpRequestInterceptor {
+		@Override
+		public ClientHttpResponse intercept(HttpRequest request, byte[] body,
+				ClientHttpRequestExecution execution) throws IOException {
+			return null;
+		}
+	}
+
+}
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