/*****************************************************************************
* Copyright (C) NanoContainer Organization. All rights reserved. *
* ------------------------------------------------------------------------- *
* The software in this package is published under the terms of the BSD *
* style license a copy of which has been included with this distribution in *
* the LICENSE.txt file. *
* *
*****************************************************************************/
package org.nanocontainer.nanowar;
import org.picocontainer.MutablePicoContainer;
import org.picocontainer.PicoContainer;
import org.picocontainer.PicoInitializationException;
import org.picocontainer.defaults.ObjectReference;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
/**
* ServletContainerFinder looks up a scoped PicoContainer in a web context. By
* default, it looks in succession in the request, session and application
* scopes. This class may be extended the
* {@link ServletContainerFinder#findContainer(HttpServletRequest)}overridden
* to provide different lookup criteria or priority.
*
* @author Stephen Molitor
* @author Mauro Talevi
*/
public class ServletContainerFinder {
/**
* Looks for a PicoContainer in succession in the request, session and
* application scopes of an HttpServletRequest.
*
* @param request the HttpServletRequest
* @return A MutablePicoContainer
* @throws PicoInitializationException
*/
public PicoContainer findContainer(HttpServletRequest request) throws PicoInitializationException {
MutablePicoContainer container = getRequestContainer(request);
if (container == null) {
container = getSessionContainer(request.getSession());
}
if (container == null) {
container = getApplicationContainer(request.getSession().getServletContext());
}
if (container == null) {
throw new PicoInitializationException("No Container found in request, session or application."
+ " Please make sure nanocontainer-nanowar is configured properly in web.xml.");
}
return container;
}
protected MutablePicoContainer getApplicationContainer(ServletContext context) {
ObjectReference ref = new ApplicationScopeObjectReference(context, KeyConstants.APPLICATION_CONTAINER);
return (MutablePicoContainer) ref.get();
}
protected MutablePicoContainer getSessionContainer(HttpSession session) {
ObjectReference ref = new SessionScopeObjectReference(session, KeyConstants.SESSION_CONTAINER);
return (MutablePicoContainer) ref.get();
}
protected MutablePicoContainer getRequestContainer(ServletRequest request) {
ObjectReference ref = new RequestScopeObjectReference(request, KeyConstants.REQUEST_CONTAINER);
return (MutablePicoContainer) ref.get();
}
}