/**
* Clears away any URNs for files that do not exist anymore.
* @param shouldClearURNSetMap true if you want to clear TIME_TO_URNSET_MAP
* too
*/
private void pruneTimes(boolean shouldClearURNSetMap) {
// if i'm using FM, always grab that lock first and then me. be quick
// about it though :)
synchronized (RouterService.getFileManager()) {
synchronized (this) {
Iterator iter = URN_TO_TIME_MAP.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry currEntry = (Map.Entry) iter.next();
if(!(currEntry.getKey() instanceof URN) ||
!(currEntry.getValue() instanceof Long)) {
iter.remove();
dirty = true;
continue;
}
URN currURN = (URN) currEntry.getKey();
Long cTime = (Long) currEntry.getValue();
// check to see if file still exists
// NOTE: technically a URN can map to multiple FDs, but I only want
// to know about one. getFileDescForUrn prefers FDs over iFDs.
FileDesc fd = RouterService.getFileManager().getFileDescForUrn(currURN);
if ((fd == null) || (fd.getFile() == null) || !fd.getFile().exists()) {
dirty = true;
iter.remove();
if (shouldClearURNSetMap)
removeURNFromURNSet(currURN, cTime);
}
}
}
}
}
/**
* Returns an List of URNs, from 'youngest' to 'oldest'.
* @param max the maximum number of URNs you want returned. if you
* want all, give Integer.MAX_VALUE.
* @param request in case the query has meta-flags, you can give it to
* me. null is fine though.
* @return a List ordered by younger URNs.
*/
public List getFiles(final QueryRequest request, final int max)
throws IllegalArgumentException {
// if i'm using FM, always grab that lock first and then me. be quick
// about it though :)
synchronized (RouterService.getFileManager()) {
synchronized (this) {
if (max < 1) throw new IllegalArgumentException("bad max = " + max);
List urnList = new ArrayList();
Iterator iter = TIME_TO_URNSET_MAP.entrySet().iterator();
final MediaType.Aggregator filter =
(request == null ? null : MediaType.getAggregator(request));
// may be non-null at loop end
List toRemove = null;
// we bank on the fact that the TIME_TO_URNSET_MAP iterator returns the
// entries in descending order....
while (iter.hasNext() && (urnList.size() < max)) {
Map.Entry currEntry = (Map.Entry) iter.next();
Set urns = (Set) currEntry.getValue();
// only put as many as desired, and possibly filter results based
// on what the query desires
Iterator innerIter = urns.iterator();
while ((urnList.size() < max) && innerIter.hasNext()) {
URN currURN = (URN) innerIter.next();
FileDesc fd =
RouterService.getFileManager().getFileDescForUrn(currURN);
// unfortunately fds can turn into ifds so ignore
if ((fd == null) || (fd instanceof IncompleteFileDesc)) {
if (toRemove == null) toRemove = new ArrayList();
toRemove.add(currURN);
continue;
}
if (filter == null) urnList.add(currURN);
else if (filter.allow(fd.getFileName())) urnList.add(currURN);
}
}
// clear any ifd's or unshared files that may have snuck into structures
if (toRemove != null) {
Iterator removees = toRemove.iterator();
while (removees.hasNext()) {
URN currURN = (URN) removees.next();
removeTime(currURN);
}
}
return urnList;
}
}
}
/**
* Constructs the TIME_TO_URNSET_MAP, which is based off the entries in the
* URN_TO_TIME_MAP.
* IMPORTANT NOTE: currently this method is not synchronized, and does not
* need to be since it is only called from the constructor (which auto-
* magically disallows concurrent acess to the instance. If this method
* is ever made public, called from multiple entrypoints, etc.,
* synchronization may be needed.
*/
private void constructURNMap() {
Set entries = URN_TO_TIME_MAP.entrySet();
Iterator iter = entries.iterator();
while (iter.hasNext()) {
// for each entry, get the creation time and the urn....
Map.Entry currEntry = (Map.Entry) iter.next();
Long cTime = (Long) currEntry.getValue();
URN urn = (URN) currEntry.getKey();
// don't ever add IFDs
if (RouterService.getFileManager().getFileDescForUrn(urn)
instanceof IncompleteFileDesc) continue;
// put the urn in a set of urns that have that creation time....
Set urnSet = (Set) TIME_TO_URNSET_MAP.get(cTime);
if (urnSet == null) {
urnSet = new HashSet();
// populate the reverse mapping
TIME_TO_URNSET_MAP.put(cTime, urnSet);
}
urnSet.add(urn);
}
}
