java.util.Map does not implement Collection, which ought to be implemented by the field to which you apply the &quot;contains&quot; operator.<br><br>If &quot;contains&quot; works with a Map, it is either a bug or not well defined or both.<br>
<br>To test whether a string  is a key (or value) in a Map, use<br>(a) if the string is a field: string memberOf (map.keySet())<br>(b) eval( map.containsKey(string) )<br><br>-W<br><br><br><div class="gmail_quote">On 29 October 2011 13:50, hdrews <span dir="ltr">&lt;<a href="mailto:heinz.drews@gmail.com">heinz.drews@gmail.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I&#39;m using in a rule the &#39;contains&#39; operator against a Map&lt;String,String&gt;.<br>

The method &#39;containsKey&#39; on Map is invoke twice, first with the key then<br>
with the value associated to the key.<br>
<br>
The rule is evaluated to &#39;false&#39;.<br>
<br>
What can I do to prevent this behavior?<br>
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