SPR-6788 - The class MediaType has a natural ordering that is inconsistent with equals, which is generally recommended or should otherwise at least be indicated in the javadoc

This commit is contained in:
Arjen Poutsma
2010-02-02 13:14:19 +00:00
parent 644f3065b6
commit 4343714c6d
6 changed files with 269 additions and 133 deletions

View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2009 the original author or authors.
* Copyright 2002-2010 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.
@@ -25,6 +25,7 @@ import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Comparator;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
@@ -40,10 +41,10 @@ import org.springframework.util.StringUtils;
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @see <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7">HTTP 1.1</a>
* @see <a href="http://tools.ietf.org/html/rfc2616#section-3.7">HTTP 1.1, section 3.7</a>
* @since 3.0
*/
public class MediaType implements Comparable<MediaType> {
public class MediaType {
public static final MediaType ALL = new MediaType("*", "*");
@@ -60,8 +61,9 @@ public class MediaType implements Comparable<MediaType> {
private final Map<String, String> parameters;
/**
* Create a new {@link MediaType} for the given primary type. <p>The {@linkplain #getSubtype() subtype} is set to
* <code>&#42;</code>, parameters empty.
* Create a new {@link MediaType} for the given primary type.
*
* <p>The {@linkplain #getSubtype() subtype} is set to <code>&#42;</code>, parameters empty.
*
* @param type the primary type
*/
@@ -90,6 +92,17 @@ public class MediaType implements Comparable<MediaType> {
this(type, subtype, Collections.singletonMap(PARAM_CHARSET, charSet.toString()));
}
/**
* Create a new {@link MediaType} for the given type, subtype, and quality value.
*
* @param type the primary type
* @param subtype the subtype
* @param qualityValue the quality value
*/
public MediaType(String type, String subtype, double qualityValue) {
this(type, subtype, Collections.singletonMap(PARAM_QUALITY_FACTORY, Double.toString(qualityValue)));
}
/**
* Create a new {@link MediaType} for the given type, subtype, and parameters.
*
@@ -100,10 +113,12 @@ public class MediaType implements Comparable<MediaType> {
public MediaType(String type, String subtype, Map<String, String> parameters) {
Assert.hasText(type, "'type' must not be empty");
Assert.hasText(subtype, "'subtype' must not be empty");
Assert.doesNotContain(type, "/", "'type' must not contain /");
Assert.doesNotContain(subtype, "/", "'subtype' must not contain /");
this.type = type.toLowerCase(Locale.ENGLISH);
this.subtype = subtype.toLowerCase(Locale.ENGLISH);
if (!CollectionUtils.isEmpty(parameters)) {
this.parameters = new LinkedCaseInsensitiveMap<String>(parameters.size());
this.parameters = new LinkedCaseInsensitiveMap<String>(parameters.size(), Locale.ENGLISH);
this.parameters.putAll(parameters);
}
else {
@@ -141,7 +156,7 @@ public class MediaType implements Comparable<MediaType> {
* @return the character set; or <code>null</code> if not available
*/
public Charset getCharSet() {
String charSet = this.parameters.get(PARAM_CHARSET);
String charSet = getParameter(PARAM_CHARSET);
return (charSet != null ? Charset.forName(charSet) : null);
}
@@ -151,7 +166,7 @@ public class MediaType implements Comparable<MediaType> {
* @return the quality factory
*/
public double getQualityValue() {
String qualityFactory = this.parameters.get(PARAM_QUALITY_FACTORY);
String qualityFactory = getParameter(PARAM_QUALITY_FACTORY);
return (qualityFactory != null ? Double.parseDouble(qualityFactory) : 1D);
}
@@ -166,8 +181,10 @@ public class MediaType implements Comparable<MediaType> {
}
/**
* Indicate whether this {@link MediaType} includes the given media type. <p>For instance, {@code text/*} includes
* {@code text/plain}, {@code text/html}, and {@code application/*+xml} includes {@code application/soap+xml}, etc.
* Indicate whether this {@link MediaType} includes the given media type.
*
* <p>For instance, {@code text/*} includes {@code text/plain}, {@code text/html}, and {@code application/*+xml}
* includes {@code application/soap+xml}, etc.
*
* @param other the reference media type with which to compare
* @return <code>true</code> if this media type includes the given media type; <code>false</code> otherwise
@@ -196,51 +213,6 @@ public class MediaType implements Comparable<MediaType> {
return isWildcardType();
}
/**
* Compare this {@link MediaType} to another. Sorting with this comparator follows the general rule: <blockquote>
* audio/basic &lt; audio/* &lt; *&#047;* </blockquote>. That is, an explicit media type is sorted before an unspecific
* media type. Quality parameters are also considered, so that <blockquote> audio/* &lt; audio/*;q=0.7;
* audio/*;q=0.3</blockquote>.
*
* @param other the media type to compare to
* @return a negative integer, zero, or a positive integer as this media type is less than, equal to, or greater than
* the specified media type
*/
public int compareTo(MediaType other) {
double qVal1 = this.getQualityValue();
double qVal2 = other.getQualityValue();
int qComp = Double.compare(qVal2, qVal1);
if (qComp != 0) {
return qComp;
}
else if (this.isWildcardType() && !other.isWildcardType()) {
return 1;
}
else if (other.isWildcardType() && !this.isWildcardType()) {
return -1;
}
else if (!this.getType().equals(other.getType())) {
return this.getType().compareTo(other.getType());
}
else { // mediaType1.getType().equals(mediaType2.getType())
if (this.isWildcardSubtype() && !other.isWildcardSubtype()) {
return 1;
}
else if (other.isWildcardSubtype() && !this.isWildcardSubtype()) {
return -1;
}
else if (!this.getSubtype().equals(other.getSubtype())) {
return this.getSubtype().compareTo(other.getSubtype());
}
else { // mediaType2.getSubtype().equals(mediaType2.getSubtype())
double quality1 = this.getQualityValue();
double quality2 = other.getQualityValue();
return Double.compare(quality2, quality1);
}
}
}
@Override
public boolean equals(Object other) {
if (this == other) {
@@ -339,8 +311,9 @@ public class MediaType implements Comparable<MediaType> {
}
/**
* Return a string representation of the given list of {@link MediaType} objects. <p>This method can be used to for an
* Accept or Content-Type header.
* Return a string representation of the given list of {@link MediaType} objects.
*
* <p>This method can be used to for an {@code Accept} or {@code Content-Type} header.
*
* @param mediaTypes the string to parse
* @return the list of media types
@@ -358,4 +331,78 @@ public class MediaType implements Comparable<MediaType> {
return builder.toString();
}
/**
* Sorts the given list of {@link MediaType} objects by specificity.
*
* <p>Given two media types:
* <ol>
* <li>if either media type has a {@linkplain #isWildcardType() wildcard type}, then the media type without the
* wildcard is ordered before the other.</li>
* <li>if the two media types have different {@linkplain #getType() types}, then they are considered equal and
* remain their current order.</li>
* <li>if either media type has a {@linkplain #isWildcardSubtype() wildcard subtype}, then the media type without
* the wildcard is sorted before the other.</li>
* <li>if the two media types have different {@linkplain #getSubtype() subtypes}, then they are considered equal
* and remain their current order.</li>
* <li>if the two media types have different {@linkplain #getQualityValue() quality value}, then the media type
* with the highest quality value is ordered before the other.</li>
* <li>if the two media types have a different amount of {@linkplain #getParameter(String) parameters}, then the
* media type with the most parameters is ordered before the other.</li>
* </ol>
*
* <p>For example:
* <blockquote>audio/basic &lt; audio/* &lt; *&#047;*</blockquote>
* <blockquote>audio/* &lt; audio/*;q=0.7; audio/*;q=0.3</blockquote>
* <blockquote>audio/basic;level=1 &lt; audio/basic</blockquote>
* <blockquote>audio/basic == text/html</blockquote>
* <blockquote>audio/basic == audio/wave</blockquote>
*
* @param mediaTypes the list of media types to be sorted
* @see <a href="http://tools.ietf.org/html/rfc2616#section-14.1">HTTP 1.1, section 14.1</a>
*/
public static void sortBySpecificity(List<MediaType> mediaTypes) {
Assert.notNull(mediaTypes, "'mediaTypes' must not be null");
if (mediaTypes.size() > 1) {
Collections.sort(mediaTypes, SPECIFICITY_COMPARATOR);
}
}
static final Comparator<MediaType> SPECIFICITY_COMPARATOR = new Comparator<MediaType>() {
public int compare(MediaType mediaType1, MediaType mediaType2) {
if (mediaType1.isWildcardType() && !mediaType2.isWildcardType()) { // */* < audio/*
return 1;
}
else if (mediaType2.isWildcardType() && !mediaType1.isWildcardType()) { // audio/* > */*
return -1;
}
else if (!mediaType1.getType().equals(mediaType2.getType())) { // audio/basic == text/html
return 0;
}
else { // mediaType1.getType().equals(mediaType2.getType())
if (mediaType1.isWildcardSubtype() && !mediaType2.isWildcardSubtype()) { // audio/* < audio/basic
return 1;
}
else if (mediaType2.isWildcardSubtype() && !mediaType1.isWildcardSubtype()) { // audio/basic > audio/*
return -1;
}
else if (!mediaType1.getSubtype().equals(mediaType2.getSubtype())) { // audio/basic == audio/wave
return 0;
}
else { // mediaType2.getSubtype().equals(mediaType2.getSubtype())
double quality1 = mediaType1.getQualityValue();
double quality2 = mediaType2.getQualityValue();
int qualityComparison = Double.compare(quality2, quality1);
if (qualityComparison != 0) {
return qualityComparison; // audio/*;q=0.7 < audio/*;q=0.3
} else {
int paramsSize1 = mediaType1.parameters.size();
int paramsSize2 = mediaType2.parameters.size();
return (paramsSize2 < paramsSize1 ? -1 : (paramsSize2 == paramsSize1 ? 0 : 1)); // audio/basic;level=1 < audio/basic
}
}
}
}
};
}

View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2009 the original author or authors.
* Copyright 2002-2010 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.
@@ -412,7 +412,7 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
public void doWithRequest(ClientHttpRequest request) throws IOException {
if (responseType != null) {
List<MediaType> allSupportedMediaTypes = new ArrayList<MediaType>();
for (HttpMessageConverter messageConverter : getMessageConverters()) {
for (HttpMessageConverter<?> messageConverter : getMessageConverters()) {
if (messageConverter.canRead(responseType, null)) {
List<MediaType> supportedMediaTypes = messageConverter.getSupportedMediaTypes();
for (MediaType supportedMediaType : supportedMediaTypes) {
@@ -425,7 +425,7 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
}
}
if (!allSupportedMediaTypes.isEmpty()) {
Collections.sort(allSupportedMediaTypes);
MediaType.sortBySpecificity(allSupportedMediaTypes);
request.getHeaders().setAccept(allSupportedMediaTypes);
}
}
@@ -458,7 +458,7 @@ public class RestTemplate extends HttpAccessor implements RestOperations {
public void doWithRequest(ClientHttpRequest httpRequest) throws IOException {
super.doWithRequest(httpRequest);
if (requestBody != null) {
Class requestType = requestBody.getClass();
Class<?> requestType = requestBody.getClass();
for (HttpMessageConverter messageConverter : getMessageConverters()) {
if (messageConverter.canWrite(requestType, requestContentType)) {
messageConverter.write(requestBody, requestContentType, httpRequest);