title: change value of field in solr based on age of document
body: <p>In my solr schema (Solr4.1) I have 2 fields</p>
  
  <pre><code>&lt;timestamp&gt;
  &lt;status&gt;
  </code></pre>
  
  <p>I want to update/change the status of documents over 14 days old but not delete them from the index.</p>
  
  <p>I delete them currently like this</p>
  
  <pre><code>curl http://localhost/solr/update?commit=true -H "Content-Type: text/xml" --data-binary '&lt;delete&gt;&lt;query&gt;timestamp:[* TO NOW-14DAYS] &lt;/query&gt;&lt;/delete&gt;'
  </code></pre>
  
  <p>im wondering if i can change the status field to some nominal text value "expired" or "archived" etc based on the documents age as determined by the timestamp value.</p>
  
  <p>Thanks</p>