{
if (pageMap instanceof AccessStackPageMap)
{
synchronized (Session.get())
{
AccessStackPageMap accessPM = (AccessStackPageMap)pageMap;
// Do we need to evict under this strategy?
if (accessPM.getVersions() > maxVersions)
{
// Remove oldest entry from access stack
final AccessStackPageMap.Access oldestAccess = (Access)accessPM.getAccessStack()
.remove(0);
final IPageMapEntry oldestEntry = pageMap.getEntry(oldestAccess.getId());
// If entry is a page (cannot be null if we're evicting)
if (oldestEntry instanceof Page)
{
Page page = (Page)oldestEntry;
// If there is more than one version of this page
if (page.getVersions() > 1)
{
// expire the oldest version
page.expireOldestVersion();
}
else
{
// expire whole page
accessPM.removeEntry(page);
}
}
else
{
// If oldestEntry is not an instance of Page, then it is
// some
// custom, user-defined IPageMapEntry class and cannot
// contain
// versioning information, so we just remove the entry.
if (oldestEntry != null)
{
accessPM.removeEntry(oldestEntry);
}
}
}
}
}