private void Remove(HitDoc hitDoc)
{
// remove from cache
if (hitDoc.doc == null)
{
// it's not in the list
return; // abort
}
if (hitDoc.next == null)
{
last = hitDoc.prev;
}
else
{
hitDoc.next.prev = hitDoc.prev;
}
if (hitDoc.prev == null)
{
first = hitDoc.next;
}
else
{
hitDoc.prev.next = hitDoc.next;
}
numDocs--;
}
private void AddToFront(HitDoc hitDoc)
{
// insert at front of cache
if (first == null)
{
last = hitDoc;
}
else
{
first.prev = hitDoc;
}
hitDoc.next = first;
first = hitDoc;
hitDoc.prev = null;
numDocs++;
}
/// <summary>Returns the stored fields of the n<sup>th</sup> document in this set.
/// <p/>Documents are cached, so that repeated requests for the same element may
/// return the same Document object.
/// </summary>
/// <throws> CorruptIndexException if the index is corrupt </throws>
/// <throws> IOException if there is a low-level IO error </throws>
public Document Doc(int n)
{
HitDoc hitDoc = HitDoc(n);
// Update LRU cache of documents
Remove(hitDoc); // remove from list, if there
AddToFront(hitDoc); // add to front of list
if (numDocs > maxDocs)
{
// if cache is full
HitDoc oldLast = last;
Remove(last); // flush last
oldLast.doc = null; // let doc get gc'd
}
if (hitDoc.doc == null)
{
hitDoc.doc = searcher.Doc(hitDoc.id); // cache miss: read document
}
return(hitDoc.doc);
}
private void Remove(HitDoc hitDoc)
{
// remove from cache
if (hitDoc.doc == null)
{
// it's not in the list
return ; // abort
}
if (hitDoc.next == null)
{
last = hitDoc.prev;
}
else
{
hitDoc.next.prev = hitDoc.prev;
}
if (hitDoc.prev == null)
{
first = hitDoc.next;
}
else
{
hitDoc.prev.next = hitDoc.next;
}
numDocs--;
}
private void AddToFront(HitDoc hitDoc)
{
// insert at front of cache
if (first == null)
{
last = hitDoc;
}
else
{
first.prev = hitDoc;
}
hitDoc.next = first;
first = hitDoc;
hitDoc.prev = null;
numDocs++;
}