JSF 1.2 and h:commandButton custom renderer problem

Question

Hi everyone!
I'm working on my custom h:commandButton renderer for a couple of hours and I cannot solve some issues...
First of all: what I want to do is to substiute default h:commandButton renderer with my own which will call standard renderer and puts some other tags. After all I will have something like that:
    <div class="leftbackground">     
       <div class="rightbackground">
           <input type="button" value="Ok" />  --- this is defaulty rendered by h:commandButton renderer
       </div>
    </div>So that I've put some lines info faces-config.xml:
<render-kit>
         <renderer>
              <component-family>javax.faces.Command</component-family>
              <renderer-type>javax.faces.Button</renderer-type>
              <renderer-class>test.MyCommandButtonRenderer</renderer-class>
         </renderer>
    </render-kit>I've written my own renderer which looks like this:
package test;
import java.io.IOException;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.Renderer;
import com.sun.faces.renderkit.html_basic.HtmlBasicRenderer;
public class MyCommandButtonRenderer extends HtmlBasicRenderer{
     public MyCommandButtonRenderer(){
          System.out.println("MyCommandButtonRenderer constructor has been calles");
     public void encodeEnd(FacesContext context, UIComponent component)
               throws IOException {
          try{
          ResponseWriter writer = context.getResponseWriter();
          writer.startElement("h3", component);
          writer.writeText("Hello from a custom JSF UI Component!", null);          
          writer.endElement("h3");  
          }catch(Exception e){
               e.printStackTrace();
}After that, when I try to call h:commandButton on my JSF page:
     <f:view>
          <h:form>
               <h:commandButton  value="Save"  />
          </h:form>
     </f:view>I can see <h3>Hello from a custom JSF UI Component!</h3>. Unfortunately my <input type="button"> isn't rendered.
I have tried something like this:
(in MyCommandRenderer}
public void encodeEnd(FacesContext context, UIComponent component)
               throws IOException {
          try{
          ResponseWriter writer = context.getResponseWriter();
          writer.startElement("h3", component);
          writer.writeText("Hello from a custom JSF UI Component!", null);          
          writer.endElement("h3");  
          String family = "javax.faces.Command";
          String renderType = "javax.faces.Button";
          Renderer baseRenderer =
               context.getRenderKit().getRenderer(family , renderType);
          baseRenderer.encodeEnd(context, component);
          }catch(Exception e){
               e.printStackTrace();
}but it obviously only rendered multiple h3 elements until StackOverflowException is being thrown (it calling himself again and again).
What am I doing wrong? Why my <input type="button"> isn't called? How to call default h:commandButton renderer and told him to render <input type=button> ? Is there any commandButton renderer class I can extend ?Which renderer is used by default by CommandButton component?
Thanks in advance for any help. I'm really close to leave off my work and stay with something more familiar ;)
Sorry for my bad English.
Looking forward to hearing from you,
Matthew
Edited by: MatthewPL on Nov 28, 2007 12:42 AM

Answer 1

To the best of my knowledge, the standard does not specify the default renderer class for any components.
I would take a wrapper/decorator approach. Add a field to your renderer for the default renderer. Before configuring your renderer, obtain the default renderer and set it on your renderer, then configure it.
OTOH, there might be easier ways for you to accomplish what you want to do. You could use a PhaseListener to add components to the view whenever a commandButton is encountered in the tree.