/**
* Method to fix the node link for an item after inserting a new node.
*
* @param item the item of the new node
* @param newNode the new node thas has been inserted.
*/
private void fixNodeLinks(Integer item, CFINode newNode) {
// get the latest node in the tree with this item
CFINode lastNode = mapItemLastNode.get(item);
if (lastNode != null) {
// if not null, then we add the new node to the node link of the last node
lastNode.nodeLink = newNode;
}
// Finally, we set the new node as the last node
mapItemLastNode.put(item, newNode);
CFINode headernode = mapItemNodes.get(item);
if (headernode == null) { // there is not
mapItemNodes.put(item, newNode);
}
}
@Override
/**
* Method for getting a string representation of the CP-tree (to be used for debugging purposes).
*
* @return a string
*/
public String toString() {
return "M" + root.toString("");
}
/**
* Add an itemset to the CFI-Tree
*
* @param itemset the itemset
* @param itemsetLength the length of the itemset
* @param support the support of the itemset
*/
public void addCFI(int[] itemset, int itemsetLength, int support) {
CFINode currentNode = root;
// For each item in the itemset
for (int i = 0; i < itemsetLength; i++) {
int item = itemset[i];
// look if there is a node already in the FP-Tree
CFINode child = currentNode.getChildWithID(item);
if (child == null) {
// there is no node, we create a new one
CFINode newNode = new CFINode();
newNode.itemID = item;
newNode.parent = currentNode;
// remember at which level in the tree that node appears
newNode.level = i + 1;
newNode.counter = support; // NEW BY PHILIPPE 2015
// we link the new node to its parrent
currentNode.childs.add(newNode);
// we take this node as the current node for the next for loop iteration
currentNode = newNode;
// We update the header table.
// We check if there is already a node with this id in the header table
fixNodeLinks(item, newNode);
} else {
// FPCLOSE:
// If there is a node already, we update it
// with the maximum of the support already in the path
// and the support of the current itemset
child.counter = Math.max(support, child.counter);
currentNode = child;
}
}
// SET THE SUPPORT OF THE CFI (the last item)
// currentNode.counter = support;
// remember that this is the last added itemset
lastAddedItemsetNode = currentNode;
}
