/**
* @param entry Entry to touch.
* @return {@code True} if queue has been changed by this call.
*/
private boolean touch(GridCacheEntry<K, V> entry) {
Node<GridCacheEntry<K, V>> node = entry.meta(meta);
// Entry has not been enqueued yet.
if (node == null) {
while (true) {
node = queue.offerLastx(entry);
if (entry.putMetaIfAbsent(meta, node) != null) {
// Was concurrently added, need to clear it from queue.
queue.unlinkx(node);
// Queue has not been changed.
return false;
} else if (node.item() != null) {
if (!entry.isCached()) {
// Was concurrently evicted, need to clear it from queue.
queue.unlinkx(node);
return false;
}
return true;
}
// If node was unlinked by concurrent shrink() call, we must repeat the whole cycle.
else if (!entry.removeMeta(meta, node)) return false;
}
}
// Entry is already in queue.
return false;
}
/** {@inheritDoc} */
@Override
public void onEntryAccessed(boolean rmv, GridCacheEntry<K, V> entry) {
if (!rmv) {
if (!entry.isCached()) return;
// Shrink only if queue was changed.
if (touch(entry)) shrink();
} else {
Node<GridCacheEntry<K, V>> node = entry.removeMeta(meta);
if (node != null) queue.unlinkx(node);
}
}
/** Shrinks FIFO queue to maximum allowed size. */
private void shrink() {
int max = this.max;
int startSize = queue.sizex();
for (int i = 0; i < startSize && queue.sizex() > max; i++) {
GridCacheEntry<K, V> entry = queue.poll();
if (entry == null) break;
if (!entry.evict()) {
entry.removeMeta(meta);
touch(entry);
}
}
}
/**
* Checks entry for empty value.
*
* @param entry Entry to check.
* @return {@code True} if entry is empty.
*/
private boolean empty(GridCacheEntry<K, V> entry) {
try {
return entry.peek(F.asList(GLOBAL)) == null;
} catch (GridException e) {
U.error(null, e.getMessage(), e);
assert false : "Should never happen: " + e;
return false;
}
}