/*
* 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.
* 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.context.request;
import javax.faces.context.FacesContext;
import org.springframework.core.NamedInheritableThreadLocal;
import org.springframework.core.NamedThreadLocal;
import org.springframework.util.ClassUtils;
/**
* Holder class to expose the web request in the form of a thread-bound
* {@link RequestAttributes} object. The request will be inherited
* by any child threads spawned by the current thread if the
* <code>inheritable<code> flag is set to <code>true</code>.
*
* <p>Use {@link RequestContextListener} or
* {@link org.springframework.web.filter.RequestContextFilter} to expose
* the current web request. Note that
* {@link org.springframework.web.servlet.DispatcherServlet} and
* {@link org.springframework.web.portlet.DispatcherPortlet} already
* expose the current request by default.
*
* @author Juergen Hoeller
* @author Rod Johnson
* @since 2.0
* @see RequestContextListener
* @see org.springframework.web.filter.RequestContextFilter
* @see org.springframework.web.servlet.DispatcherServlet
* @see org.springframework.web.portlet.DispatcherPortlet
*/
public abstract class RequestContextHolder {
private static final boolean jsfPresent =
ClassUtils.isPresent("javax.faces.context.FacesContext", RequestContextHolder.class.getClassLoader());
private static final ThreadLocal<RequestAttributes> requestAttributesHolder =
new NamedThreadLocal<RequestAttributes>("Request attributes");
private static final ThreadLocal<RequestAttributes> inheritableRequestAttributesHolder =
new NamedInheritableThreadLocal<RequestAttributes>("Request context");
/**
* Reset the RequestAttributes for the current thread.
*/
public static void resetRequestAttributes() {
requestAttributesHolder.remove();
inheritableRequestAttributesHolder.remove();
}
/**
* Bind the given RequestAttributes to the current thread,
* <i>not</i> exposing it as inheritable for child threads.
* @param attributes the RequestAttributes to expose
* @see #setRequestAttributes(RequestAttributes, boolean)
*/
public static void setRequestAttributes(RequestAttributes attributes) {
setRequestAttributes(attributes, false);
}
/**
* Bind the given RequestAttributes to the current thread.
* @param attributes the RequestAttributes to expose,
* or <code>null</code> to reset the thread-bound context
* @param inheritable whether to expose the RequestAttributes as inheritable
* for child threads (using an {@link java.lang.InheritableThreadLocal})
*/
public static void setRequestAttributes(RequestAttributes attributes, boolean inheritable) {
if (attributes == null) {
resetRequestAttributes();
}
else {
if (inheritable) {
inheritableRequestAttributesHolder.set(attributes);
requestAttributesHolder.remove();
}
else {
requestAttributesHolder.set(attributes);
inheritableRequestAttributesHolder.remove();
}
}
}
/**
* Return the RequestAttributes currently bound to the thread.
* @return the RequestAttributes currently bound to the thread,
* or <code>null</code> if none bound
*/
public static RequestAttributes getRequestAttributes() {
RequestAttributes attributes = requestAttributesHolder.get();
if (attributes == null) {
attributes = inheritableRequestAttributesHolder.get();
}
return attributes;
}
/**
* Return the RequestAttributes currently bound to the thread.
* <p>Exposes the previously bound RequestAttributes instance, if any.
* Falls back to the current JSF FacesContext, if any.
* @return the RequestAttributes currently bound to the thread
* @throws IllegalStateException if no RequestAttributes object
* is bound to the current thread
* @see #setRequestAttributes
* @see ServletRequestAttributes
* @see FacesRequestAttributes
* @see javax.faces.context.FacesContext#getCurrentInstance()
*/
public static RequestAttributes currentRequestAttributes() throws IllegalStateException {
RequestAttributes attributes = getRequestAttributes();
if (attributes == null) {
if (jsfPresent) {
attributes = FacesRequestAttributesFactory.getFacesRequestAttributes();
}
if (attributes == null) {
throw new IllegalStateException("No thread-bound request found: " +
"Are you referring to request attributes outside of an actual web request, " +
"or processing a request outside of the originally receiving thread? " +
"If you are actually operating within a web request and still receive this message, " +
"your code is probably running outside of DispatcherServlet/DispatcherPortlet: " +
"In this case, use RequestContextListener or RequestContextFilter to expose the current request.");
}
}
return attributes;
}
/**
* Inner class to avoid hard-coded JSF dependency.
*/
private static class FacesRequestAttributesFactory {
public static RequestAttributes getFacesRequestAttributes() {
FacesContext facesContext = FacesContext.getCurrentInstance();
return (facesContext != null ? new FacesRequestAttributes(facesContext) : null);
}
}
}
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