Attribute not found on Apache Tiles

Question

I'm using Apache Tiles on a Sprint MVC app and I have this tiles.xml:

<tiles-definitions>
    <definition name="defaultLayout" template="/WEB-INF/tiles/template/defaultLayout.jsp">
        <put-attribute name="title" value="" />
        <put-attribute name="header" value="/WEB-INF/tiles/template/header.jsp" />
        <put-attribute name="content" value=""/>
        <put-attribute name="footer" value="/WEB-INF/tiles/template/footer.jsp" />
    </definition>

    <definition name="home" extends="defaultLayout">
        <put-attribute name="title" value="Alsa" />
        <put-attribute name="content" value="/WEB-INF/pages/home.jsp" />
        <put-attribute name="active" value="index" />
    </definition>
</tiles-definitions>

What I'm trying to do is use the attribute active to add a class to active menu item. For that I have this in header.jsp:

<%@ taglib uri="http://tiles.apache.org/tags-tiles-extras" prefix="tilesx" %>

<tilesx:useAttribute name="active" />

The problem is that everytime I try to render the page I get this error:

org.apache.tiles.template.NoSuchAttributeException: Error importing attributes. Attribute 'active' is null

What am I doing wrong?

Answer 1

The trick here is to add cascade=true to your attribute so that it will be available to nested definitions and templates.

 <definition name="home" extends="defaultLayout">
        <put-attribute name="title"   value="Alsa" />
        <put-attribute name="content" value="/WEB-INF/pages/home.jsp" />
        <put-attribute name="active"  value="index" cascade="true"/>
    </definition>

See: https://tiles.apache.org/framework/tutorial/advanced/nesting-extending.html

Answer 2

You may need to declare the class. You'll also need id.

<tilesx:useAttribute name="active" id="active" class="java.lang.String"/>

Also if there are other tiles definitions in your app other than "home" and if any of them do not define an "active" attribute, you may want to set "ignore" to true as part of your definition to avoid runtime errors. More here:https://tiles.apache.org/framework/tiles-jsp/tlddoc/index.html