Why it cannot find the setter method for the attribute in my custom tag?

Question

Hi, i have a custom tag like this:
<robin:category tModelKey="#{data.tModelKey}" > </robin:category>And in my tld file:
<tag>
      <name>category</name>
     <tag-class>category.component.HtmlCategoryTag</tag-class>
     <attribute>
         <name>tModelKey</name>
         <required>false</required>
         <rtexprvalue>false</rtexprvalue>
         <type>java.lang.String</type>
     </attribute>
</tag>
........................................and in my HtmlCategoryTag Class
public class HtmlCategoryTag extends HtmlPanelGridTag
private String tModelKey;
public String getTModelKey()
return tModelKey;
public void setTModelKey(String modelKey)
tModelKey = modelKey;
So,you see,generally speaking,to use a custom tag,we only to write a tag class,declare it in the tld file,nothing more.
What fints me is that if i change "tModelKey" to "test" and change the according part in the tag class , tld file and jsp file, the "setter not found" problem no longer exists,everything goes right!!!.
So why this happens? please help:)
Best Regards:)
Robin

Answer 1

Then you also need to create a UI element that extends HtmlPanelGrid
that has a tModelKey member and getters/setters. That object will hold
the information so that you can use it in your bean.Whoops... ignore that! Sorry. Attributes are simply stored in the component map component.getAttributes().
Add to your Tag class:
public void setProperties(UIComponent component) {
    super.setProperties(component);
    Tags.setString(component, "tModelKey", tModelKey);
public void release() {
    // see above
}Where Tags.java is:public class Tags {
    public static void setString(UIComponent component, String attributeName, String attributeValue) {
        if (attributeValue != null) {
            if (UIComponentTag.isValueReference(attributeValue)) {
                setValueBinding(component, attributeName, attributeValue);
            } else {
                component.getAttributes().put(attributeName, attributeValue);
    public static void setValueBinding(UIComponent component, String attributeName, String attributeValue) {
        FacesContext context = FacesContext.getCurrentInstance();
        Application app = context.getApplication();
        ValueBinding vb = app.createValueBinding(attributeValue);
        component.setValueBinding(attributeName, vb);
}