Check if a map contains a specific key in Freemarker
<p>In Java:</p>

<pre><code>Map&lt;String, Object&gt; model = new HashMap&lt;&gt;();
Map&lt;String, String&gt; items = new HashMap&lt;&gt;();
items.put("color", "red");
model.put("items", items);
</code></pre>

<p>I now want to include a snippet in my rendered template if <code>items</code> contains the key <code>color</code>.</p>

<pre><code>&lt;#if ???? &gt;
   the map contains a key called color
&lt;/#if&gt;
</code></pre>

<p>What do I replace the ???? with?</p>