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https://issues.apache.org/jira/browse/CXF-7716?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16449123#comment-16449123
]
ASF GitHub Bot commented on CXF-7716:
-------------------------------------
reta commented on a change in pull request #407: [CXF-7716] Reduce
StringBuilders and other performance changes.
URL: https://github.com/apache/cxf/pull/407#discussion_r183578479
##########
File path:
rt/frontend/jaxrs/src/main/java/org/apache/cxf/jaxrs/utils/JAXRSUtils.java
##########
@@ -1508,11 +1509,40 @@ public static boolean matchMimeTypes(MediaType
requestContentType,
}
}
}
-
return new ArrayList<>(supportedMimeTypeList);
+ }
+
+ public static boolean doMimeTypesIntersect(List<MediaType>
requiredMediaTypes, List<MediaType> userMediaTypes) {
+ for (MediaType requiredType : requiredMediaTypes) {
Review comment:
Turned out to be quite tricky ... but I have one suggestion for you. Here is
the implementation for `doMimeTypesIntersect` and `intersectMimeTypes`:
```
public static List<MediaType> intersectMimeTypes(List<MediaType>
requiredMediaTypes,
List<MediaType>
userMediaTypes,
boolean
addRequiredParamsIfPossible,
boolean
addDistanceParameter) {
final AccumulatingConsumer consumer = new
AccumulatingConsumer(addRequiredParamsIfPossible, addDistanceParameter);
intersectMimeTypes(requiredMediaTypes, userMediaTypes, consumer);
return new ArrayList<>(consumer.supportedMimeTypeList);
}
public static boolean doMimeTypesIntersect(List<MediaType>
requiredMediaTypes, List<MediaType> userMediaTypes) {
final NonAccumulatingConsumer consumer = new
NonAccumulatingConsumer();
intersectMimeTypes(requiredMediaTypes, userMediaTypes, consumer);
return consumer.doIntersect;
}
```
Here is the initial `intersectMimeTypes` function, refactored to use
consumers, the part which is was accumulating (or returning `true`) is now part
of the consumers:
```
private static void intersectMimeTypes(List<MediaType> requiredMediaTypes,
List<MediaType> userMediaTypes,
BiConsumer<MediaType, MediaType> consumer) {
for (MediaType requiredType : requiredMediaTypes) {
for (MediaType userType : userMediaTypes) {
boolean isCompatible = isMediaTypeCompatible(requiredType,
userType);
if (isCompatible) {
boolean parametersMatched = true;
for (Map.Entry<String, String> entry :
userType.getParameters().entrySet()) {
String value =
requiredType.getParameters().get(entry.getKey());
if (value != null && entry.getValue() != null
&& !(stripDoubleQuotesIfNeeded(value).equals(
stripDoubleQuotesIfNeeded(entry.getValue())))) {
if (HTTP_CHARSET_PARAM.equals(entry.getKey())
&& value.equalsIgnoreCase(entry.getValue()))
{
continue;
}
parametersMatched = false;
break;
}
}
if (!parametersMatched) {
continue;
}
consumer.accept(requiredType, userType);
}
}
}
}
```
And finally, two consumers:
```
private static class NonAccumulatingConsumer implements
BiConsumer<MediaType, MediaType> {
private boolean doIntersect;
@Override
public void accept(MediaType t, MediaType u) {
doIntersect = true;
}
}
```
And
```
private static class AccumulatingConsumer implements
BiConsumer<MediaType, MediaType> {
private final Set<MediaType> supportedMimeTypeList = new
LinkedHashSet<MediaType>();
private final boolean addRequiredParamsIfPossible;
private final boolean addDistanceParameter;
private AccumulatingConsumer(boolean addRequiredParamsIfPossible,
boolean addDistanceParameter) {
this.addRequiredParamsIfPossible = addRequiredParamsIfPossible;
this.addDistanceParameter = addDistanceParameter;
}
@Override
public void accept(MediaType requiredType, MediaType userType) {
boolean requiredTypeWildcard =
requiredType.getType().equals(MediaType.MEDIA_TYPE_WILDCARD);
boolean requiredSubTypeWildcard =
requiredType.getSubtype().contains(MediaType.MEDIA_TYPE_WILDCARD);
String type = requiredTypeWildcard ? userType.getType() :
requiredType.getType();
String subtype = requiredSubTypeWildcard ? userType.getSubtype()
: requiredType.getSubtype();
Map<String, String> parameters = userType.getParameters();
if (addRequiredParamsIfPossible) {
parameters = new LinkedHashMap<String, String>(parameters);
for (Map.Entry<String, String> entry :
requiredType.getParameters().entrySet()) {
if (!parameters.containsKey(entry.getKey())) {
parameters.put(entry.getKey(), entry.getValue());
}
}
}
if (addDistanceParameter) {
int distance = 0;
if (requiredTypeWildcard) {
distance++;
}
if (requiredSubTypeWildcard) {
distance++;
}
parameters.put(MEDIA_TYPE_DISTANCE_PARAM,
Integer.toString(distance));
}
supportedMimeTypeList.add(new MediaType(type, subtype,
parameters));
}
}
```
Ideally, would be good to move to a dedicated utility class, but roughly
this is an idea. What do you think. @WhiteCat22, does it make sense?
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> IBM Performance Team has found several performance increases
> ------------------------------------------------------------
>
> Key: CXF-7716
> URL: https://issues.apache.org/jira/browse/CXF-7716
> Project: CXF
> Issue Type: Bug
> Components: JAX-RS
> Affects Versions: 3.0.15, 3.2.4
> Reporter: Adam Anderson
> Priority: Major
> Fix For: 3.2.5
>
> Original Estimate: 1h
> Remaining Estimate: 1h
>
> Our performance team has identified several areas of improvement to reduce
> garbage collection and CPU usage.
> First, we reduced the amount of StringBuilders created in HTTPUtils.java and
> ResourceUtils.java.
> Second, we created JAXRSUtils.doMimeTypesIntersect() - a method similar to
> JAXRSUtils.intersectMimeTypes - that doesn't create a HashSet but instead
> returns a boolean when we just need to know if they intersect.
> Third, we found that getting the annotations for parameters to create
> constructor arguments in PerRequestResourceProvider.java is expensive, so we
> cache them in the constructor instead of getting them via reflection every
> request.
> These changes combined result in a ~1.5-2% performance increase.
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