/**
* return the head entry in the list preserving the cupipe requirement of at least one entry left
* in the list
*/
private LRUClockNode getHeadEntry() {
synchronized (lock) {
LRUClockNode aNode = NewLRUClockHand.this.head.nextLRUNode();
if (aNode == this.tail) {
return null;
}
LRUClockNode next = aNode.nextLRUNode();
this.head.setNextLRUNode(next);
next.setPrevLRUNode(this.head);
aNode.setNextLRUNode(null);
aNode.setPrevLRUNode(null);
this.size++;
return aNode;
}
}
/** remove an entry from the pipe... (marks it evicted to be skipped later) */
public boolean unlinkEntry(LRUClockNode entry) {
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(LocalizedStrings.NewLRUClockHand_UNLINKENTRY_CALLED, entry));
}
entry.setEvicted();
stats().incDestroys();
synchronized (lock) {
LRUClockNode next = entry.nextLRUNode();
LRUClockNode prev = entry.prevLRUNode();
if (next == null || prev == null) {
// not in the list anymore.
return false;
}
next.setPrevLRUNode(prev);
prev.setNextLRUNode(next);
entry.setNextLRUNode(null);
entry.setPrevLRUNode(null);
}
return true;
}
/**
* Adds a new lru node for the entry between the current tail and head of the list.
*
* @param aNode Description of the Parameter
*/
public final void appendEntry(final LRUClockNode aNode) {
synchronized (this.lock) {
if (aNode.nextLRUNode() != null || aNode.prevLRUNode() != null) {
return;
}
if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
logger.trace(
LogMarker.LRU_CLOCK,
LocalizedMessage.create(
LocalizedStrings.NewLRUClockHand_ADDING_ANODE_TO_LRU_LIST, aNode));
}
aNode.setNextLRUNode(this.tail);
this.tail.prevLRUNode().setNextLRUNode(aNode);
aNode.setPrevLRUNode(this.tail.prevLRUNode());
this.tail.setPrevLRUNode(aNode);
this.size++;
}
}