Lucene querybean - cocoon 2.11

Hi,

I am using  a querybean to generate a Lucene index.

The sitemap pattern is ( adapted from the sample block :

<map:match pattern="create.html">
                 <map:call function="indexCollection">
                     <map:parameter name="screen" value="screen/indexer"/>
                     <map:parameter name="lucene-directory" value="{global:lucene-directory}"/>
                     <map:parameter name="lucene-analyzer" value="{global:lucene-analyzer}"/>
                     <map:parameter name="lucene-merge-factor" value="10"/>
                     <map:parameter name="lucene-create-index" value="false"/>
                     <map:parameter name="lucene-content" value="cocoon:/prepare4indexing/"/>
                     <map:parameter name="content-directory" value="../BB/xml"/>
                     <map:parameter name="include-pattern" value=".xml$"/>
                     <map:parameter name="result-directory" value=""/>
                     <map:parameter name="result-suffix" value=""/>
                 </map:call>
  </map:match>

Please:

 1. What's the $ in <map:parameter name="include-pattern" value=".xml$"/>  for?
 2. Is there any way of excluding a file from being indexed on the value of one of its attributes?

Thanks

Peter