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/**********************************************************************************
Copyright (c) 2018 Apereo Foundation

Licensed under the Educational Community 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://opensource.org/licenses/ecl2

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.sakaiproject.jsf2.app;

import java.util.Iterator;
import java.util.List;
import java.util.Vector;

import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpSession;

/**
 * 
 * MessageSaver has utility methods to save FacesMessage objects from one request to the next request (the messages are saved attributes of the current HttpSession).
 * 
 */
public class MessageSaver
{
	/** The session attribute name used to store the latest batch of messages. */
	public static final String ATTR_MSGS = "org.sakaiproject.jsf2.messages";

	/**
	 * Restore saved messages.
	 * 
	 * @param context
	 *        The current faces context.
	 */
	public static void restoreMessages(FacesContext context)
	{
		if (context == null) return;

		// look in the session
		HttpSession s = (HttpSession) context.getExternalContext().getSession(false);
		if (s == null) return;

		// get messages
		List msgs = (List) s.getAttribute(ATTR_MSGS);
		if (msgs != null)
		{
			// process each one - add it to this context's message set
			for (Iterator iMessages = msgs.iterator(); iMessages.hasNext();)
			{
				FacesMessage msg = (FacesMessage) iMessages.next();
				// Note: attributed to no specific tree element
				context.addMessage(null, msg);
			}

			s.removeAttribute(ATTR_MSGS);
		}
	}

	/**
	 * Save current messages for later restoration.
	 * 
	 * @param context
	 *        The current faces context.
	 */
	public static void saveMessages(FacesContext context)
	{
		if (context == null) return;

		// look in the session
		HttpSession s = (HttpSession) context.getExternalContext().getSession(false);
		if (s == null) return;

		// collect the messages from the context for restoration on the next rendering
		List msgs = new Vector();
		for (Iterator iMessages = context.getMessages(); iMessages.hasNext();)
		{
			FacesMessage msg = (FacesMessage) iMessages.next();
			msgs.add(msg);
		}

		// store the messages for this mode to find
		s.setAttribute(ATTR_MSGS, msgs);
	}
}