/*
* 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.support;
import java.io.File;
import javax.servlet.ServletContext;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ApplicationObjectSupport;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.util.WebUtils;
/**
* Convenient superclass for application objects running in a WebApplicationContext.
* Provides <code>getWebApplicationContext()</code>, <code>getServletContext()</code>,
* and <code>getTempDir()</code> methods.
*
* @author Juergen Hoeller
* @since 28.08.2003
* @see SpringBeanAutowiringSupport
*/
public abstract class WebApplicationObjectSupport extends ApplicationObjectSupport
implements ServletContextAware {
private ServletContext servletContext;
public final void setServletContext(ServletContext servletContext) {
if (servletContext != this.servletContext) {
this.servletContext = servletContext;
if (servletContext != null) {
initServletContext(servletContext);
}
}
}
/**
* Overrides the base class behavior to enforce running in an ApplicationContext.
* All accessors will throw IllegalStateException if not running in a context.
* @see #getApplicationContext()
* @see #getMessageSourceAccessor()
* @see #getWebApplicationContext()
* @see #getServletContext()
* @see #getTempDir()
*/
@Override
protected boolean isContextRequired() {
return true;
}
/**
* Calls {@link #initServletContext(javax.servlet.ServletContext)} if the
* given ApplicationContext is a {@link WebApplicationContext}.
*/
@Override
protected void initApplicationContext(ApplicationContext context) {
super.initApplicationContext(context);
if (this.servletContext == null && context instanceof WebApplicationContext) {
this.servletContext = ((WebApplicationContext) context).getServletContext();
if (this.servletContext != null) {
initServletContext(this.servletContext);
}
}
}
/**
* Subclasses may override this for custom initialization based
* on the ServletContext that this application object runs in.
* <p>The default implementation is empty. Called by
* {@link #initApplicationContext(org.springframework.context.ApplicationContext)}
* as well as {@link #setServletContext(javax.servlet.ServletContext)}.
* @param servletContext the ServletContext that this application object runs in
* (never <code>null</code>)
*/
protected void initServletContext(ServletContext servletContext) {
}
/**
* Return the current application context as WebApplicationContext.
* <p><b>NOTE:</b> Only use this if you actually need to access
* WebApplicationContext-specific functionality. Preferably use
* <code>getApplicationContext()</code> or <code>getServletContext()</code>
* else, to be able to run in non-WebApplicationContext environments as well.
* @throws IllegalStateException if not running in a WebApplicationContext
* @see #getApplicationContext()
*/
protected final WebApplicationContext getWebApplicationContext() throws IllegalStateException {
ApplicationContext ctx = getApplicationContext();
if (ctx instanceof WebApplicationContext) {
return (WebApplicationContext) getApplicationContext();
}
else if (isContextRequired()) {
throw new IllegalStateException("WebApplicationObjectSupport instance [" + this +
"] does not run in a WebApplicationContext but in: " + ctx);
}
else {
return null;
}
}
/**
* Return the current ServletContext.
* @throws IllegalStateException if not running within a ServletContext
*/
protected final ServletContext getServletContext() throws IllegalStateException {
if (this.servletContext != null) {
return this.servletContext;
}
ServletContext servletContext = getWebApplicationContext().getServletContext();
if (servletContext == null && isContextRequired()) {
throw new IllegalStateException("WebApplicationObjectSupport instance [" + this +
"] does not run within a ServletContext. Make sure the object is fully configured!");
}
return servletContext;
}
/**
* Return the temporary directory for the current web application,
* as provided by the servlet container.
* @return the File representing the temporary directory
* @throws IllegalStateException if not running within a ServletContext
* @see org.springframework.web.util.WebUtils#getTempDir(javax.servlet.ServletContext)
*/
protected final File getTempDir() throws IllegalStateException {
return WebUtils.getTempDir(getServletContext());
}
}
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