Nesting templates in Tiles, why are attributes undefined in the included template?

Question

I use Tiles 2 in my web application, and the basic setup I've got in my tiles.xml file is this:

<tiles-definitions>
    <definition name="mainLayout" template="/jsp/layout.jsp">
        <put-attribute name="header" value=""/>
        <put-attribute name="menu" value="/jsp/defaultMenu.jsp" />
        <put-attribute name="content" value="" />
        <put-attribute name="footer" value="/jsp/footer.jsp" />
    </definition>

    <definition name="HomePage" extends="mainLayout">
        <put-attribute name="content" type="template" value="/jsp/home.jsp"/>
        <put-attribute name="homeClass" value="active" />
    </definition>

    ... rest omitted for brevity.

In layout.jsp, which defines the layout, I include the menu in the appropriate place.

<tiles:insertAttribute name="menu" />

So, then inside my menu template, I wanted to use the homeClass attribute defined in tiles.xml.

<tiles:insertAttribute name='homeClass'/>

but I get an error about the homeClass attribute not being defined. If I do an insertAttribute in my layout.jsp, the value is defined properly, but I need it defined in the menu JSP, included from my layout.

So, my question is: How can I have the homeClass attribute passed correctly not just to my layout template, but to the menu template which is included from the layout template?

Nested tiles get their own attribute space - which is why homeClass is undefined - but never fear: you can define it in both places — nont, Nov 03 '10 at 20:15

score 3 · Accepted Answer · answered Nov 03 '10 at 20:03

I believe you could use nested template definitions:

<definition name="mainLayout" template="/jsp/layout.jsp">
        <put-attribute name="header" value=""/>

        <put-attribute name="menu">
            <definition template="/jsp/defaultMenu.jsp">
                <put-attribute name="homeClass" value="active"/>
            </definition>
         </put-attribute>

        <put-attribute name="content" value="" />
        <put-attribute name="footer" value="/jsp/footer.jsp" />
    </definition>

Nesting templates in Tiles, why are attributes undefined in the included template?

1 Answers1