Add ExtractingResponseErrorHandler

This commit introduces ExtractingResponseErrorHandler: an alternative
ResponseErrorHandler that uses `HttpMessageConverter`s to convert HTTP
error responses to `RestClientException`.

Issue: SPR-15544

spring-web/src/test/java/org/springframework/web/client/ExtractingResponseErrorHandlerTests.java

@@ -0,0 +1,170 @@
+/*
+ * Copyright 2002-2017 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.web.client;
+
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
+
+import static org.junit.Assert.*;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.*;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class ExtractingResponseErrorHandlerTests {
+
+	private ExtractingResponseErrorHandler errorHandler;
+
+	private final ClientHttpResponse response = mock(ClientHttpResponse.class);
+
+	@Before
+	public void setUp() throws Exception {
+		HttpMessageConverter<Object> converter = new MappingJackson2HttpMessageConverter();
+		this.errorHandler = new ExtractingResponseErrorHandler(
+				Collections.singletonList(converter));
+
+		this.errorHandler.setStatusMapping(
+				Collections.singletonMap(HttpStatus.I_AM_A_TEAPOT, MyRestClientException.class));
+		this.errorHandler.setSeriesMapping(Collections
+				.singletonMap(HttpStatus.Series.SERVER_ERROR, MyRestClientException.class));
+		this.errorHandler.afterPropertiesSet();
+	}
+
+	@Test
+	public void hasError() throws Exception {
+		given(this.response.getStatusCode()).willReturn(HttpStatus.I_AM_A_TEAPOT);
+		assertTrue(this.errorHandler.hasError(this.response));
+
+		given(this.response.getStatusCode()).willReturn(HttpStatus.INTERNAL_SERVER_ERROR);
+		assertTrue(this.errorHandler.hasError(this.response));
+
+		given(this.response.getStatusCode()).willReturn(HttpStatus.OK);
+		assertFalse(this.errorHandler.hasError(this.response));
+	}
+
+	@Test
+	public void handleErrorStatusMatch() throws Exception {
+		given(this.response.getStatusCode()).willReturn(HttpStatus.I_AM_A_TEAPOT);
+		HttpHeaders responseHeaders = new HttpHeaders();
+		responseHeaders.setContentType(MediaType.APPLICATION_JSON);
+		given(this.response.getHeaders()).willReturn(responseHeaders);
+
+		byte[] body = "{\"foo\":\"bar\"}".getBytes(StandardCharsets.UTF_8);
+		responseHeaders.setContentLength(body.length);
+		given(this.response.getBody()).willReturn(new ByteArrayInputStream(body));
+
+		try {
+			this.errorHandler.handleError(this.response);
+			fail("MyRestClientException expected");
+		}
+		catch (MyRestClientException ex) {
+			assertEquals("bar", ex.getFoo());
+		}
+	}
+
+	@Test
+	public void handleErrorSeriesMatch() throws Exception {
+		given(this.response.getStatusCode()).willReturn(HttpStatus.INTERNAL_SERVER_ERROR);
+		HttpHeaders responseHeaders = new HttpHeaders();
+		responseHeaders.setContentType(MediaType.APPLICATION_JSON);
+		given(this.response.getHeaders()).willReturn(responseHeaders);
+
+		byte[] body = "{\"foo\":\"bar\"}".getBytes(StandardCharsets.UTF_8);
+		responseHeaders.setContentLength(body.length);
+		given(this.response.getBody()).willReturn(new ByteArrayInputStream(body));
+
+		try {
+			this.errorHandler.handleError(this.response);
+			fail("MyRestClientException expected");
+		}
+		catch (MyRestClientException ex) {
+			assertEquals("bar", ex.getFoo());
+		}
+	}
+
+	@Test
+	public void handleNoMatch() throws Exception {
+		given(this.response.getStatusCode()).willReturn(HttpStatus.NOT_FOUND);
+		HttpHeaders responseHeaders = new HttpHeaders();
+		responseHeaders.setContentType(MediaType.APPLICATION_JSON);
+		given(this.response.getHeaders()).willReturn(responseHeaders);
+
+		byte[] body = "{\"foo\":\"bar\"}".getBytes(StandardCharsets.UTF_8);
+		responseHeaders.setContentLength(body.length);
+		given(this.response.getBody()).willReturn(new ByteArrayInputStream(body));
+
+		try {
+			this.errorHandler.handleError(this.response);
+			fail("HttpClientErrorException expected");
+		}
+		catch (HttpClientErrorException ex) {
+			assertEquals(HttpStatus.NOT_FOUND, ex.getStatusCode());
+			assertArrayEquals(body, ex.getResponseBodyAsByteArray());
+		}
+	}
+
+	@Test
+	public void handleNoMatchOverride() throws Exception {
+		this.errorHandler.setSeriesMapping(Collections
+				.singletonMap(HttpStatus.Series.CLIENT_ERROR, null));
+		given(this.response.getStatusCode()).willReturn(HttpStatus.NOT_FOUND);
+		HttpHeaders responseHeaders = new HttpHeaders();
+		responseHeaders.setContentType(MediaType.APPLICATION_JSON);
+		given(this.response.getHeaders()).willReturn(responseHeaders);
+
+		byte[] body = "{\"foo\":\"bar\"}".getBytes(StandardCharsets.UTF_8);
+		responseHeaders.setContentLength(body.length);
+		given(this.response.getBody()).willReturn(new ByteArrayInputStream(body));
+
+		this.errorHandler.handleError(this.response);
+	}
+
+	@SuppressWarnings("serial")
+	private static class MyRestClientException extends RestClientException {
+
+		private String foo;
+
+		public MyRestClientException(String msg) {
+			super(msg);
+		}
+
+		public MyRestClientException(String msg, Throwable ex) {
+			super(msg, ex);
+		}
+
+		public String getFoo() {
+			return this.foo;
+		}
+
+		public void setFoo(String foo) {
+			this.foo = foo;
+		}
+	}
+
+}