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WebAsyncUtils avoids reflection for creating StandardServletAsyncWebRequest

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Issue: SPR-13112
This commit is contained in:
Juergen Hoeller
2015-06-11 10:13:51 +02:00
parent 4eea675c15
commit 32b9ea9e9f
1 changed files with 20 additions and 23 deletions
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43
spring-web/src/main/java/org/springframework/web/context/request/async/WebAsyncUtils.java
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@@ -1,5 +1,5 @@
/*
* Copyright 2002-2012 the original author or authors.
* Copyright 2002-2015 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.
@@ -13,14 +13,13 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.context.request.async;
import java.lang.reflect.Constructor;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.BeanUtils;
import org.springframework.util.ClassUtils;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.WebRequest;
@@ -29,13 +28,15 @@ import org.springframework.web.context.request.WebRequest;
* Utility methods related to processing asynchronous web requests.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 3.2
*/
public abstract class WebAsyncUtils {
public static final String WEB_ASYNC_MANAGER_ATTRIBUTE = WebAsyncManager.class.getName() + ".WEB_ASYNC_MANAGER";
private static Constructor<?> standardAsyncRequestConstructor;
// Determine whether Servlet 3.0's ServletRequest.startAsync method is available
private static final boolean startAsyncAvailable = ClassUtils.hasMethod(ServletRequest.class, "startAsync");
/**
@@ -66,31 +67,27 @@ public abstract class WebAsyncUtils {
}
/**
* Create an AsyncWebRequest instance. By default an instance of
* {@link StandardServletAsyncWebRequest} is created if running in Servlet
* 3.0 (or higher) environment or as a fallback, an instance of
* {@link NoSupportAsyncWebRequest} is returned.
*
* Create an AsyncWebRequest instance. By default, an instance of
* {@link StandardServletAsyncWebRequest} gets created when running in
* Servlet 3.0 (or higher) environment - as a fallback, an instance
* of {@link NoSupportAsyncWebRequest} will be returned.
* @param request the current request
* @param response the current response
* @return an AsyncWebRequest instance, never {@code null}
* @return an AsyncWebRequest instance (never {@code null})
*/
public static AsyncWebRequest createAsyncWebRequest(HttpServletRequest request, HttpServletResponse response) {
return ClassUtils.hasMethod(ServletRequest.class, "startAsync") ?
createStandardServletAsyncWebRequest(request, response) : new NoSupportAsyncWebRequest(request, response);
return (startAsyncAvailable ? AsyncWebRequestFactory.createStandardAsyncWebRequest(request, response) :
new NoSupportAsyncWebRequest(request, response));
}
private static AsyncWebRequest createStandardServletAsyncWebRequest(HttpServletRequest request, HttpServletResponse response) {
try {
if (standardAsyncRequestConstructor == null) {
String className = "org.springframework.web.context.request.async.StandardServletAsyncWebRequest";
Class<?> clazz = ClassUtils.forName(className, WebAsyncUtils.class.getClassLoader());
standardAsyncRequestConstructor = clazz.getConstructor(HttpServletRequest.class, HttpServletResponse.class);
}
return (AsyncWebRequest) BeanUtils.instantiateClass(standardAsyncRequestConstructor, request, response);
}
catch (Throwable t) {
throw new IllegalStateException("Failed to instantiate StandardServletAsyncWebRequest", t);
/**
* Inner class to avoid a hard dependency on the Servlet 3.0 API.
*/
private static class AsyncWebRequestFactory {
public static AsyncWebRequest createStandardAsyncWebRequest(HttpServletRequest request, HttpServletResponse response) {
return new StandardServletAsyncWebRequest(request, response);
}
}