/**
* Get an array of search results for other editions of the title
* represented by this record (empty if unavailable). In most cases,
* this will use the XISSN/XISBN logic to find matches.
*
* @return mixed Editions in index engine result format (or null if no
* hits, or PEAR_Error object).
* @access public
*/
public function getEditions()
{
include_once 'sys/WorldCatUtils.php';
$wc = new WorldCatUtils();
// Try to build an array of OCLC Number, ISBN or ISSN-based sub-queries:
$parts = array();
$oclcNum = $this->getCleanOCLCNum();
if (!empty($oclcNum)) {
$oclcList = $wc->getXOCLCNUM($oclcNum);
foreach ($oclcList as $current) {
$parts[] = "oclc_num:" . $current;
}
}
$isbn = $this->getCleanISBN();
if (!empty($isbn)) {
$isbnList = $wc->getXISBN($isbn);
foreach ($isbnList as $current) {
$parts[] = 'isbn:' . $current;
}
}
$issn = $this->getCleanISSN();
if (!empty($issn)) {
$issnList = $wc->getXISSN($issn);
foreach ($issnList as $current) {
$parts[] = 'issn:' . $current;
}
}
// If we have query parts, we should try to find related records:
if (!empty($parts)) {
// Limit the number of parts based on the boolean clause limit:
$index = $this->getIndexEngine();
$limit = $index->getBooleanClauseLimit();
if (count($parts) > $limit) {
$parts = array_slice($parts, 0, $limit);
}
// Assemble the query parts and filter out current record:
$query = '(' . implode(' OR ', $parts) . ') NOT id:"' . addcslashes($this->getUniqueID(), '"') . '"';
// Perform the search and return either results or an error:
$result = $index->search($query, null, null, 0, 5);
if (PEAR::isError($result)) {
return $result;
}
if (isset($result['response']['docs']) && !empty($result['response']['docs'])) {
return $result['response']['docs'];
}
}
// If we got this far, we were unable to find any results:
return null;
}
