Another quick tip here: if you're working with the Apache Solr module, specifically looking at the documents that are being created from your nodes, and you want to print out the document and have a look at what fields and values are on your $document
then if you did this:
// Print the $document using the devel dpm function.
dpm($document);
Then you would get a very unhelpful output from Krumo, because all the fields on the $document
are protected, and so the devel module can't access them. Instead you can do this:
dpm(array_combine($document->getFieldNames(), $document->getFieldValues()));
And you'll get a nice array...