freemarker : cast "Interface" Object to the real concret class
<p>I iterate to a list of IColonne object. But I need to cast to the concret class to get specific attribut. My list have "Colonne" and "ColonneGroup" object.</p>

<p>The IColonne interface :</p>

<pre><code>public interface IColonne {
    String getFtlName();
    int getWidthPx(final int tableSize);
}
</code></pre>

<p>The Colonne concrete class:</p>

<pre><code>public class Colonne implements IColonne {
    ....
}
</code></pre>

<p>The ColonneGroup concret class :</p>

<pre><code>public class ColonneGroup implements IColonne {
    private List&lt;String&gt; texts;
}
</code></pre>

<p>I need to access to access to the "texts" attribut. But I have "only" IColonne. So I need to cast to ColonneGroup. How can I do this?</p>