Override RichFaces Message renderer with Bootstrap alert design

faces-config.xml

<render-kit>
        <renderer>
            <component-family>javax.faces.Messages</component-family>
            <renderer-type>org.richfaces.MessagesRenderer</renderer-type>
            <renderer-class>your.package.RichMessagesRenderer</renderer-class>
        </renderer>
</render-kit>

RichMessagesRenderer.java

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.faces.application.FacesMessage;
import javax.faces.application.FacesMessage.Severity;
import javax.faces.component.UIComponent;
import javax.faces.component.UIMessages;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.FacesRenderer;
import javax.faces.render.Renderer;

@FacesRenderer(componentFamily="javax.faces.Messages", rendererType="org.richfaces.MessagesRenderer")
public class RichMessagesRenderer extends Renderer {
    
    @Override
    public void encodeEnd(FacesContext facesContext, UIComponent component) throws IOException{
        if(!component.isRendered()) {
            return;
        }
        
        UIMessages uiMessages = (UIMessages) component;
        ResponseWriter writer = facesContext.getResponseWriter();
        
        assert(writer != null);
        
        String clientId = uiMessages.getClientId(facesContext);
        Iterator<FacesMessage> allMessages = uiMessages.isGlobalOnly() ? facesContext.getMessages(null) : facesContext.getMessages();
        
        Map<Severity, List<FacesMessage>> messages = new HashMap<Severity, List<FacesMessage>>();
        messages.put(FacesMessage.SEVERITY_INFO, new ArrayList<FacesMessage>()); // Bootstrap info
        messages.put(FacesMessage.SEVERITY_WARN, new ArrayList<FacesMessage>()); // Bootstrap warning
        messages.put(FacesMessage.SEVERITY_ERROR, new ArrayList<FacesMessage>()); // Bootstrap error
        messages.put(FacesMessage.SEVERITY_FATAL, new ArrayList<FacesMessage>()); // Bootstrap error
        
        while (allMessages.hasNext()){
            FacesMessage message = allMessages.next();
            
            if(message.isRendered() && !uiMessages.isRedisplay()) {
                continue;
            }
            
            messages.get(message.getSeverity()).add(message);
        }
        
        writer.startElement("div", uiMessages);
        writer.writeAttribute("id", clientId, "id");

        List<FacesMessage> severityMessages = messages.get(FacesMessage.SEVERITY_FATAL);
        if (severityMessages.size() > 0){
            encodeSeverityMessages(facesContext, uiMessages, FacesMessage.SEVERITY_FATAL, severityMessages);
        }
        
        severityMessages = messages.get(FacesMessage.SEVERITY_ERROR);
        if (severityMessages.size() > 0){
            encodeSeverityMessages(facesContext, uiMessages, FacesMessage.SEVERITY_ERROR, severityMessages);
        }
        
        severityMessages = messages.get(FacesMessage.SEVERITY_WARN);
        if (severityMessages.size() > 0){
            encodeSeverityMessages(facesContext, uiMessages, FacesMessage.SEVERITY_WARN, severityMessages);
        }
        
        severityMessages = messages.get(FacesMessage.SEVERITY_INFO);
        if (severityMessages.size() > 0){
            encodeSeverityMessages(facesContext, uiMessages, FacesMessage.SEVERITY_INFO, severityMessages);
        }
            
        writer.endElement("div");
    }

    private void encodeSeverityMessages(FacesContext facesContext, UIMessages uiMessages, Severity severity, List<FacesMessage> messages) throws IOException {
        ResponseWriter writer = facesContext.getResponseWriter();
        
        String alertSeverityClass = "";
        
        if(FacesMessage.SEVERITY_INFO.equals(severity)) {
            alertSeverityClass = "alert-info";
        }
        else if(FacesMessage.SEVERITY_WARN.equals(severity)) {
            alertSeverityClass = ""; // Default alert is a warning
        }
        else if(FacesMessage.SEVERITY_ERROR.equals(severity)) {
            alertSeverityClass = "alert-error";
        }
        else if(FacesMessage.SEVERITY_FATAL.equals(severity)) {
            alertSeverityClass = "alert-error";
        }
        
        writer.startElement("div", null);
        
        writer.writeAttribute("class", "rf alert fade in alert-block " + alertSeverityClass, null);
        
        writer.startElement("a", null);
        writer.writeAttribute("class", "close", null);
        writer.writeAttribute("data-dismiss","alert", null);
        writer.writeAttribute("href", "#", null);
        writer.write("&times;");
        writer.endElement("a");
        
        writer.startElement("ul", null);
        for (FacesMessage msg : messages){
            String summary = msg.getSummary() != null ? msg.getSummary() : "";
            String detail = msg.getDetail() != null ? msg.getDetail() : summary;
            
            writer.startElement("li", null);

            if (uiMessages.isShowSummary()){
                writer.startElement("strong", null);
                writer.writeText(summary, null);
                writer.endElement("strong");
            }
            
            if (uiMessages.isShowDetail()){
                writer.writeText(" "+detail, null);
            }
            
            writer.endElement("li");
            msg.rendered();
        }
        writer.endElement("ul");
        writer.endElement("div");
    }
}

see https://gist.github.com/4151211 for JSF version