Added response HttpHeaders to HttpStatusCodeException and subclasses

Default HTTP errors from RestTemplate now include the response headers
in addition to the response body.  In particular, this enables
inspection of the Content-Type header allowing manual deserialization
of the response body without guessing as to the content type.

* introduced HttpStatusCodeException#getResponseHeaders
* added constructor with headers param for HttpStatusCodeException,
  HttpClientErrorException and HttpServerErrorException
* preserved exsisting constructor signatures
* marked HttpHeaders as Serializable
* generated new serialVersionUID where needed

Issue: SPR-7938

Author: scothis

Diff for: spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.http;
 
+import java.io.Serializable;
 import java.net.URI;
 import java.nio.charset.Charset;
 import java.text.ParseException;
@@ -54,7 +55,9 @@
  * @author Arjen Poutsma
  * @since 3.0
  */
-public class HttpHeaders implements MultiValueMap<String, String> {
+public class HttpHeaders implements MultiValueMap<String, String>, Serializable {
+
+	private static final long serialVersionUID = -8578554704772377436L;
 
 	private static final String ACCEPT = "Accept";
 

Diff for: spring-web/src/main/java/org/springframework/web/client/DefaultResponseErrorHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -20,6 +20,7 @@
 import java.io.InputStream;
 import java.nio.charset.Charset;
 
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.client.ClientHttpResponse;
@@ -68,14 +69,15 @@ protected boolean hasError(HttpStatus statusCode) {
 	 */
 	public void handleError(ClientHttpResponse response) throws IOException {
 		HttpStatus statusCode = response.getStatusCode();
-		MediaType contentType = response.getHeaders().getContentType();
+		HttpHeaders headers = response.getHeaders();
+		MediaType contentType = headers.getContentType();
 		Charset charset = contentType != null ? contentType.getCharSet() : null;
 		byte[] body = getResponseBody(response);
 		switch (statusCode.series()) {
 			case CLIENT_ERROR:
-				throw new HttpClientErrorException(statusCode, response.getStatusText(), body, charset);
+				throw new HttpClientErrorException(statusCode, response.getStatusText(), headers, body, charset);
 			case SERVER_ERROR:
-				throw new HttpServerErrorException(statusCode, response.getStatusText(), body, charset);
+				throw new HttpServerErrorException(statusCode, response.getStatusText(), headers, body, charset);
 			default:
 				throw new RestClientException("Unknown status code [" + statusCode + "]");
 		}

Diff for: spring-web/src/main/java/org/springframework/web/client/HttpClientErrorException.java

@@ -18,6 +18,7 @@
 
 import java.nio.charset.Charset;
 
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 
 /**
@@ -29,7 +30,7 @@
  */
 public class HttpClientErrorException extends HttpStatusCodeException {
 
-	private static final long serialVersionUID = 6777393766937023392L;
+	private static final long serialVersionUID = 5177019431887513952L;
 
 	/**
 	 * Construct a new instance of {@code HttpClientErrorException} based on a {@link HttpStatus}.
@@ -63,4 +64,22 @@ public HttpClientErrorException(HttpStatus statusCode,
 			Charset responseCharset) {
 		super(statusCode, statusText, responseBody, responseCharset);
 	}
+
+	/**
+	 * Construct a new instance of {@code HttpClientErrorException} based on a {@link HttpStatus}, status text, and
+	 * response body content.
+	 *
+	 * @param statusCode	  the status code
+	 * @param statusText	  the status text
+	 * @param responseHeaders the response headers, may be {@code null}
+	 * @param responseBody	the response body content, may be {@code null}
+	 * @param responseCharset the response body charset, may be {@code null}
+	 */
+	public HttpClientErrorException(HttpStatus statusCode,
+			String statusText,
+			HttpHeaders responseHeaders,
+			byte[] responseBody,
+			Charset responseCharset) {
+		super(statusCode, statusText, responseHeaders, responseBody, responseCharset);
+	}
 }

Diff for: spring-web/src/main/java/org/springframework/web/client/HttpServerErrorException.java

@@ -18,6 +18,7 @@
 
 import java.nio.charset.Charset;
 
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 
 /**
@@ -29,7 +30,7 @@
  */
 public class HttpServerErrorException extends HttpStatusCodeException {
 
-	private static final long serialVersionUID = -2565832100451369997L;
+	private static final long serialVersionUID = -2915754006618138282L;
 
 	/**
 	 * Construct a new instance of {@code HttpServerErrorException} based on a {@link HttpStatus}.
@@ -66,4 +67,23 @@ public HttpServerErrorException(HttpStatus statusCode,
 			Charset responseCharset) {
 		super(statusCode, statusText, responseBody, responseCharset);
 	}
+
+	/**
+	 * Construct a new instance of {@code HttpServerErrorException} based on a {@link HttpStatus}, status text, and
+	 * response body content.
+	 *
+	 * @param statusCode	  the status code
+	 * @param statusText	  the status text
+	 * @param responseHeaders the response headers, may be {@code null}
+	 * @param responseBody	the response body content, may be {@code null}
+	 * @param responseCharset the response body charset, may be {@code null}
+	 * @since 3.2.0
+	 */
+	public HttpServerErrorException(HttpStatus statusCode,
+			String statusText,
+			HttpHeaders responseHeaders,
+			byte[] responseBody,
+			Charset responseCharset) {
+		super(statusCode, statusText, responseHeaders, responseBody, responseCharset);
+	}
 }

Diff for: spring-web/src/main/java/org/springframework/web/client/HttpStatusCodeException.java

@@ -19,6 +19,7 @@
 import java.io.UnsupportedEncodingException;
 import java.nio.charset.Charset;
 
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 
 /**
@@ -30,7 +31,7 @@
  */
 public abstract class HttpStatusCodeException extends RestClientException {
 
-	private static final long serialVersionUID = 1549626836533638803L;
+	private static final long serialVersionUID = -5807494703720513267L;
 
 	private static final String DEFAULT_CHARSET = "ISO-8859-1";
 
@@ -40,6 +41,8 @@ public abstract class HttpStatusCodeException extends RestClientException {
 
 	private final byte[] responseBody;
 
+	private final HttpHeaders responseHeaders;
+
 	private final String responseCharset;
 
 	/**
@@ -48,7 +51,7 @@ public abstract class HttpStatusCodeException extends RestClientException {
 	 * @param statusCode the status code
 	 */
 	protected HttpStatusCodeException(HttpStatus statusCode) {
-		this(statusCode, statusCode.name(), null, null);
+		this(statusCode, statusCode.name(), null, null, null);
 	}
 
 	/**
@@ -58,7 +61,7 @@ protected HttpStatusCodeException(HttpStatus statusCode) {
 	 * @param statusText the status text
 	 */
 	protected HttpStatusCodeException(HttpStatus statusCode, String statusText) {
-		this(statusCode, statusText, null, null);
+		this(statusCode, statusText, null, null, null);
 	}
 
 	/**
@@ -75,9 +78,29 @@ protected HttpStatusCodeException(HttpStatus statusCode,
 			String statusText,
 			byte[] responseBody,
 			Charset responseCharset) {
+		this(statusCode, statusText, null, responseBody, responseCharset);
+	}
+
+	/**
+	 * Construct a new instance of {@code HttpStatusCodeException} based on a {@link HttpStatus}, status text, and
+	 * response body content.
+	 *
+	 * @param statusCode	  the status code
+	 * @param statusText	  the status text
+	 * @param responseHeaders the response headers, may be {@code null}
+	 * @param responseBody	the response body content, may be {@code null}
+	 * @param responseCharset the response body charset, may be {@code null}
+	 * @since 3.2.0
+	 */
+	protected HttpStatusCodeException(HttpStatus statusCode,
+			String statusText,
+			HttpHeaders responseHeaders,
+			byte[] responseBody,
+			Charset responseCharset) {
 		super(statusCode.value() + " " + statusText);
 		this.statusCode = statusCode;
 		this.statusText = statusText;
+		this.responseHeaders = responseHeaders;
 		this.responseBody = responseBody != null ? responseBody : new byte[0];
 		this.responseCharset = responseCharset != null ? responseCharset.name() : DEFAULT_CHARSET;
 	}
@@ -96,6 +119,15 @@ public String getStatusText() {
 		return this.statusText;
 	}
 
+	/**
+	 * Returns the HTTP response headers.
+	 *
+	 * @since 3.2.0
+	 */
+	public HttpHeaders getResponseHeaders() {
+		return this.responseHeaders;
+	}
+
 	/**
 	 * Returns the response body as a byte array.
 	 *

Diff for: spring-web/src/test/java/org/springframework/web/client/DefaultResponseErrorHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -29,7 +29,9 @@
 
 import static org.easymock.EasyMock.*;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /** @author Arjen Poutsma */
 public class DefaultResponseErrorHandlerTests {
@@ -64,7 +66,7 @@ public void hasErrorFalse() throws Exception {
 		verify(response);
 	}
 
-	@Test(expected = HttpClientErrorException.class)
+	@Test
 	public void handleError() throws Exception {
 		HttpHeaders headers = new HttpHeaders();
 		headers.setContentType(MediaType.TEXT_PLAIN);
@@ -76,7 +78,13 @@ public void handleError() throws Exception {
 
 		replay(response);
 
-		handler.handleError(response);
+		try {
+			handler.handleError(response);
+			fail("expected HttpClientErrorException");
+		}
+		catch (HttpClientErrorException e) {
+			assertSame(headers, e.getResponseHeaders());
+		}
 
 		verify(response);
 	}