How to propagate FacesMessage between two jsf pages

Hello,

The JSF don’t propagate a FacesMessage between two jsf pages, i discovery this when i trying to make something like this:

1 -
User click in a Jsf Button

2 - Call the action method in the Managed Bean, something like this:

	public String someMethod(){
		// Execute some code
		FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_INFO, "", "Something message");
		FacesContext.getCurrentInstance().addMessage(null, msg);
		return "otherPage";
	}

3 - Suppose that the string “otherPage” cause a normal redirect to other Jsf page, through faces-config.xml, in this exact point the FacesMessage is losted.

Resolution: For resolve this problem, follow this steps, basically this will affect all lifecycle of your jsf application:

1 - In your faces-config.xml, put this code:

  <lifecycle>
    <phase-listener>com.somepackage.MultiPageMessagesSupport</phase-listener>  
  </lifecycle>

2 – Put the below java class in the package specified above:

import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;

/**
 * Enables messages to be rendered on different pages from which they were set.
 * To produce this behaviour, this class acts as a <code>PhaseListener</code>.
 * 
 * This is performed by moving the FacesMessage objects:
 * <li>After each phase where messages may be added, this moves the messages
 * from the page-scoped FacesContext to the session-scoped session map.
 * <li>Before messages are rendered, this moves the messages from the
 * session-scoped session map back to the page-scoped FacesContext.
 * 
 * Only messages that are not associated with a particular component are ever
 * moved. These are the only messages that can be rendered on a page that is
 * different from where they originated. * To enable this behaviour, add a
 * <code>lifecycle</code> block to your faces-config.xml file. That block
 * should contain a single <code>phase-listener</code> block containing the
 * fully-qualified classname of this file.
 * 
 * @author <a href="mailto:jesse@odel.on.ca">Jesse Wilson</a>
 * 
 * @version This version have the bug corrected: The bug was:
 * In the same page, the FacesMessage was displayed many times,
 * with this patch, only different messages is added into new context.
 */
public class MultiPageMessagesSupport implements PhaseListener {

	private static final long serialVersionUID = 3328743500652081238L;

	/** a name to save messages in the session under */
	private static final String sessionToken = "MULTI_PAGE_MESSAGES_SUPPORT";

	/**
	 * Return the identifier of the request processing phase during which this
	 * listener is interested in processing PhaseEvent events.
	 */
	public PhaseId getPhaseId() {
		return PhaseId.ANY_PHASE;
	}

	/**
	 * Handle a notification that the processing for a particular phase of the
	 * request processing lifecycle is about to begin.
	 */
	public void beforePhase(PhaseEvent event) {
		if (event.getPhaseId() == PhaseId.RENDER_RESPONSE) {
			FacesContext facesContext = event.getFacesContext();
			restoreMessages(facesContext);
		}
	}

	/**
	 * Handle a notification that the processing for a particular phase has just
	 * been completed.
	 */
	public void afterPhase(PhaseEvent event) {
		if (event.getPhaseId() == PhaseId.APPLY_REQUEST_VALUES
				|| event.getPhaseId() == PhaseId.PROCESS_VALIDATIONS
				|| event.getPhaseId() == PhaseId.INVOKE_APPLICATION) {
			FacesContext facesContext = event.getFacesContext();
			saveMessages(facesContext);
		}
	}

	/**
	 * Remove the messages that are not associated with any particular component
	 * from the faces context and store them to the user's session.
	 * 
	 * @return the number of removed messages.
	 */
	@SuppressWarnings("unchecked")
	private int saveMessages(FacesContext facesContext) {
		// remove messages from the context
		Set<FacesMessage> messages = new HashSet<FacesMessage>();
		for (Iterator i = facesContext.getMessages(null); i.hasNext();) {
			FacesMessage msg = (FacesMessage) i.next();
			messages.add(msg);
			i.remove();
		}
		// store them in the session
		if (messages.size() == 0)
			return 0;
		Map sessionMap = facesContext.getExternalContext().getSessionMap();
		// if there already are messages
		Set<FacesMessage> existingMessages = (Set<FacesMessage>) sessionMap
				.get(sessionToken);
		if (existingMessages != null) {
			existingMessages.addAll(messages);
			// if these are the first messages
		} else {
			sessionMap.put(sessionToken, messages);
		}
		return messages.size();
	}

	/**
	 * Remove the messages that are not associated with any particular component
	 * from the user's session and add them to the faces context.
	 * 
	 * @return the number of removed messages.
	 */
	@SuppressWarnings("unchecked")
	private int restoreMessages(FacesContext facesContext) {
		// remove messages from the session
		Map sessionMap = facesContext.getExternalContext().getSessionMap();
		Set<FacesMessage> messages = (Set<FacesMessage>) sessionMap
				.remove(sessionToken);
		// store them in the context
		if (messages == null)
			return 0;
		int restoredCount = messages.size();

		// set that contains wich messages already exists in the FacesContext
		Set<FacesMessage> facesContextMessages = new HashSet<FacesMessage>();
		for (Iterator i = facesContext.getMessages(null); i.hasNext();) {
			FacesMessage msg = (FacesMessage) i.next();
			facesContextMessages.add(msg);
			i.remove();
		}

		// add the messages that aren't in the FacesContext 
		for (FacesMessage facesMessage : messages) {
			if (!facesContextMessages.contains(facesMessage))
				facesContext.addMessage(null, facesMessage);
		}
		return restoredCount;
	}
}
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