org.springframework.web.jsf.FacesContextUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2014 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
*
* https://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.jsf;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.util.WebUtils;
/**
* Convenience methods to retrieve Spring's root {@link WebApplicationContext}
* for a given JSF {@link FacesContext}. This is useful for accessing a
* Spring application context from custom JSF-based code.
*
* Analogous to Spring's WebApplicationContextUtils for the ServletContext.
*
* @author Juergen Hoeller
* @since 1.1
* @see org.springframework.web.context.ContextLoader
* @see org.springframework.web.context.support.WebApplicationContextUtils
*/
public abstract class FacesContextUtils {
/**
* Find the root {@link WebApplicationContext} for this web app, typically
* loaded via {@link org.springframework.web.context.ContextLoaderListener}.
*
Will rethrow an exception that happened on root context startup,
* to differentiate between a failed context startup and no context at all.
* @param fc the FacesContext to find the web application context for
* @return the root WebApplicationContext for this web app, or {@code null} if none
* @see org.springframework.web.context.WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE
*/
@Nullable
public static WebApplicationContext getWebApplicationContext(FacesContext fc) {
Assert.notNull(fc, "FacesContext must not be null");
Object attr = fc.getExternalContext().getApplicationMap().get(
WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
if (attr == null) {
return null;
}
if (attr instanceof RuntimeException) {
throw (RuntimeException) attr;
}
if (attr instanceof Error) {
throw (Error) attr;
}
if (!(attr instanceof WebApplicationContext)) {
throw new IllegalStateException("Root context attribute is not of type WebApplicationContext: " + attr);
}
return (WebApplicationContext) attr;
}
/**
* Find the root {@link WebApplicationContext} for this web app, typically
* loaded via {@link org.springframework.web.context.ContextLoaderListener}.
*
Will rethrow an exception that happened on root context startup,
* to differentiate between a failed context startup and no context at all.
* @param fc the FacesContext to find the web application context for
* @return the root WebApplicationContext for this web app
* @throws IllegalStateException if the root WebApplicationContext could not be found
* @see org.springframework.web.context.WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE
*/
public static WebApplicationContext getRequiredWebApplicationContext(FacesContext fc) throws IllegalStateException {
WebApplicationContext wac = getWebApplicationContext(fc);
if (wac == null) {
throw new IllegalStateException("No WebApplicationContext found: no ContextLoaderListener registered?");
}
return wac;
}
/**
* Return the best available mutex for the given session:
* that is, an object to synchronize on for the given session.
*
Returns the session mutex attribute if available; usually,
* this means that the HttpSessionMutexListener needs to be defined
* in {@code web.xml}. Falls back to the Session reference itself
* if no mutex attribute found.
*
The session mutex is guaranteed to be the same object during
* the entire lifetime of the session, available under the key defined
* by the {@code SESSION_MUTEX_ATTRIBUTE} constant. It serves as a
* safe reference to synchronize on for locking on the current session.
*
In many cases, the Session reference itself is a safe mutex
* as well, since it will always be the same object reference for the
* same active logical session. However, this is not guaranteed across
* different servlet containers; the only 100% safe way is a session mutex.
* @param fc the FacesContext to find the session mutex for
* @return the mutex object (never {@code null})
* @see org.springframework.web.util.WebUtils#SESSION_MUTEX_ATTRIBUTE
* @see org.springframework.web.util.HttpSessionMutexListener
*/
@Nullable
public static Object getSessionMutex(FacesContext fc) {
Assert.notNull(fc, "FacesContext must not be null");
ExternalContext ec = fc.getExternalContext();
Object mutex = ec.getSessionMap().get(WebUtils.SESSION_MUTEX_ATTRIBUTE);
if (mutex == null) {
mutex = ec.getSession(true);
}
return mutex;
}
}