/**
* Gives back the relevant node based on the given radius
*
* @param position starting point to calculate recommendation
* @param radius defines how many levels above start position should be incorporated
*/
public INode collectNode(INode position, int radius) {
INode relevantNode = null;
// Going one level up if radius parameter stills allows it
if (radius > 0) {
if (!position.isRoot()) {
INode parent = position.getParent();
relevantNode = collectNode(parent, radius - 1);
} else {
relevantNode = position;
}
} else {
relevantNode = position;
}
return relevantNode;
}
/**
* Collect all the content that should be recommended based on given user and radius
*
* @param position starting point to calculate recommendation
* @param radiusU defines how many levels of users should be incorporated
* @param radiusC defines how many levels of content should be incorporated
*/
public Map<INode, IAttribute> recommend(INode position, int radiusU, int radiusC) {
Map<INode, IAttribute> recommendation = new HashMap<INode, IAttribute>();
// Find relevant User
INode relUser = collectNode(position, radiusU);
System.out.println("starting recommendation from user node: " + relUser.toString());
// collect leaf content nodes from relUser content items
Set<INode> userAttributes = relUser.getAttributeKeys();
for (INode content : userAttributes) {
Map<INode, IAttribute> contentLeafNodes = collectLeaves(content, null);
for (INode leafNode : contentLeafNodes.keySet()) {
recommendation.put(leafNode, contentLeafNodes.get(leafNode));
}
}
return recommendation;
}
/**
* Gives back the leaf nodes related to a given node
*
* @param position this node is the starting point to find leaves
* @param leaves collection of all leaves
*/
public Map<INode, IAttribute> collectLeaves(INode position, Map<INode, IAttribute> leaves) {
// Create leaves set if not exists
if (leaves == null) {
leaves = new HashMap<INode, IAttribute>();
}
// If position is leaf
if (position.isLeaf()) {
System.out.println(position.getAttributesString());
leaves.put(position, position.getAttributeValue(position));
return leaves;
}
// If position is no leaf
Iterator<INode> children = position.getChildren();
while (children.hasNext()) {
INode child = children.next();
Map<INode, IAttribute> tempLeaves = (collectLeaves(child, leaves));
for (INode tempLeaf : tempLeaves.keySet()) {
if (!leaves.keySet().contains(tempLeaf)) {
leaves.put(tempLeaf, tempLeaf.getAttributeValue(tempLeaf));
}
}
}
return leaves;
}
/**
* Runs a test that compares the tree calculation with the real values of a given user This
* recommendation type allows to calculate an RMSE value that indicates the quality of the
* recommendations produced by the clusterer
*/
public Map<Integer, IAttribute> runTestRecommendation(INode testNode) {
// Find position of the similar node in the tree
INode position = leavesMapU.get((int) testNode.getDatasetId());
if (position == null) {
return null;
} else {
// Collect ratings of all content given by the input node
Map<Integer, IAttribute> contentRatings = collectRatings(position, testNode, null);
return contentRatings;
}
}
/**
* Collect ratings of all content given by the input node
*
* @param position this is the starting point for collecting
* @param inputNodeID this node defines the content that needs to be collected
*/
public Map<Integer, IAttribute> collectRatings(
INode position, INode testNode, Map<Integer, IAttribute> contentRatings) {
// Create Map for content of test user with empty values if not existing
if (contentRatings == null) {
contentRatings = new HashMap<Integer, IAttribute>(); // DatasetID, AttributeData
Set<INode> testContentKeys = testNode.getAttributeKeys();
for (INode testContentKey : testContentKeys) {
contentRatings.put((int) testContentKey.getDatasetId(), null);
}
}
// Look for content nodes on the list and add it to collected ratings map
Set<INode> posContentKeys = position.getAttributeKeys();
Map<Integer, IAttribute> posContentMap = new HashMap<Integer, IAttribute>();
for (INode posContentKey : posContentKeys) {
// Find Dataset ID of Content Node -> FIXME: very inefficient
int contentDatasetID = 0;
for (Iterator<Entry<Integer, INode>> iter = leavesMapC.entrySet().iterator();
iter.hasNext(); ) {
Map.Entry<Integer, INode> e = (Map.Entry<Integer, INode>) iter.next();
if (posContentKey.getId() == e.getValue().getId()) {
contentDatasetID = e.getKey();
}
}
posContentMap.put(contentDatasetID, position.getAttributeValue(posContentKey));
}
for (Entry<Integer, IAttribute> contentRating : contentRatings.entrySet()) {
int datasetID = contentRating.getKey();
IAttribute rating = contentRating.getValue();
// Check if value still needs to be found
if (rating == null) {
try {
IAttribute contentAttributes = posContentMap.get(datasetID);
contentRatings.put(datasetID, posContentMap.get(datasetID));
} catch (Exception e) {
System.out.println(e);
}
}
}
// Check if all movies were found
if (contentRatings.containsValue(null) != true) {
return contentRatings;
} else {
// Go one level up if possible
if (position.getParent() != null) {
contentRatings = collectRatings(position.getParent(), testNode, contentRatings);
if (contentRatings != null) {
return contentRatings;
}
} else {
return contentRatings;
}
}
return null;
}