Re: Handling and displaying action errors

[Jeff Bischoff]

Julian,

I like the methods you guys have for setting error messages. Seems that 
some JSF books lack such relatively basic information (e.g. Core 
JavaServer Faces)!

Since we have nothing in the Wiki about error reporting, perhaps it 
would be useful to make such an entry. I could make a page describing a 
stripped-down version of your methodology, unless you have the time to 
make one yourself?

Regards,

Jeff Bischoff
Kenneth L Kurz & Assoc, Inc.

Julian Ray wrote:
Here you go.

We include this file in every page 

<%@ taglib uri="http://java.sun.com/jsf/html"; prefix="h"%>
<%@ taglib uri="http://java.sun.com/jsf/core"; prefix="f"%>
<%@ taglib uri="http://myfaces.apache.org/tomahawk"; prefix="t"%>
<%@ taglib uri="http://c2glogistics.com/cms"; prefix="cms"%>

<h:panelGrid styleClass="group" columns="2" cellpadding="2" cellspacing="0"
width="100%" columnClasses="buttonCol, leftAlignCol"
rowClasses="vertAlignTop" rendered="#{! empty facesContext.maximumSeverity}"

        <h:graphicImage value="#{PageMessages.messageImage}" style="float:
left; vertical-align: top;" />  
        <h:panelGrid columns="1" cellpadding="2" cellspacing="2"
columnClasses="leftAlignCol" rowClasses="vertAlignTop" width="100%">   
            <h:outputText value="#{PageMessages.messageHeader}"
escape="false" rendered="#{PageMessages.renderMessage}"/>
            <h:messages errorClass="errorMessage" infoClass="infoMessage"
layout="table" globalOnly="true" showDetail="false" showSummary="true"/>
        </h:panelGrid>
</h:panelGrid>

It is backed up by a request-scoped backing bean which knows how to place
message-specific images into the page

import javax.faces.application.FacesMessage;
import javax.faces.application.FacesMessage.Severity;

import org.apache.commons.lang.StringUtils;

import cms.beans.Messages;

public class PageMessages extends AbstractUIBean {
        private static final long serialVersionUID = -6479897299239746841L;
        private static final String BEAN_NAME =
PageMessages.class.getName();
    private String messageHeader;
    private String messageImage;
    private Severity severityLevel;

    public PageMessages() {

        messageHeader = null;
        
        // See if there are messages queued for the page
        severityLevel = getFacesContext().getMaximumSeverity();
        if (null != severityLevel) {
            getLogger().debug("Severity Level Trapped: level = '" +
severityLevel.toString() + "'");
            if (severityLevel.compareTo(FacesMessage.SEVERITY_ERROR) == 0) {
                messageHeader = Messages.getString("PAGE_MESSAGE_ERROR");
                messageImage = "resources/warning.gif";
            } else if (severityLevel.compareTo(FacesMessage.SEVERITY_INFO)
== 0) {
                messageHeader = null;
                messageImage = "resources/information.gif";
            } else if (severityLevel.compareTo(FacesMessage.SEVERITY_WARN)
== 0) {
                messageHeader = null;
                messageImage = "resources/warning.gif";
            } else if (severityLevel.compareTo(FacesMessage.SEVERITY_FATAL)
== 0) {
                messageHeader = Messages.getString("PAGE_FATAL_ERROR");
                messageImage = "resources/stop.gif";
            }
        } else {
            getLogger().debug("Severity Level Trapped: level = 'null'");
        }
    }
    public Boolean getRenderMessage() {
        return new Boolean(StringUtils.isNotBlank(getMessageHeader()));
    }
    /*
     * Local Methods
     */
    /*
     * Overrides
     */
    public String getBeanName() {
        return BEAN_NAME;
    }

    /*
     * Actions
     */
    /*
     * Listeners
     */
    /*
     * Validators
     */
    /*
     * Accessors
     */
    public String getMessageHeader() {
        return messageHeader;
    }
    public String getMessageImage() {
        return messageImage;
    }
}
        

-----Original Message-----
From: Aleksei Valikov [mailto:[EMAIL PROTECTED] 
Sent: Friday, May 26, 2006 6:19 AM
To: MyFaces Discussion
Subject: Re: Handling and displaying action errors

Hi.


The action method bindings of the backing beans process the request 
and can determine the next view through returning a navigation 
control. Null re-displays the current view so you can set up logic 
which goes

If (someBusinessLogic()) {
        displayConfirmationMessage();
        return myNextView;
} else {
        displayErrorMessage();
        return null;
}

We have a message area included on each JSP page which processes 
actions and inform the user of processing outcomes by using the 
Message interface and sending warnings, errors and info messages. Each 
of our backing beans inherits the following

   protected void setInfoMessage(String msg) {
       getFacesContext().addMessage(null, new 
FacesMessage(FacesMessage.SEVERITY_INFO, msg, null));
   }

   protected void setWarnMessage(String msg) {
       getFacesContext().addMessage(null, new 
FacesMessage(FacesMessage.SEVERITY_WARN, msg, null));
   }
   protected void setErrorMessage(String msg) {
       getFacesContext().addMessage(null, new 
FacesMessage(FacesMessage.SEVERITY_ERROR, msg, null));
   }


Well, this looks fine. So you just queue a message for the null client id?
How do you display messages for null within the mage? Could you please post
the corresponding code for the message area?

Thank you.

Bye.
/lexi