public StructuredRetrieval(StructuredIndex index, Parameters factoryParameters) {
this.index = index;
Parameters featureParameters = factoryParameters.clone();
featureParameters.add("collectionLength", Long.toString(index.getCollectionLength()));
featureParameters.add("documentCount", Long.toString(index.getDocumentCount()));
featureFactory = new FeatureFactory(featureParameters);
}
/**
* Evaluates a query.
*
* @param queryTree A query tree that has been already transformed with
* StructuredRetrieval.transformQuery.
* @param requested The number of documents to retrieve, at most.
* @return
* @throws java.lang.Exception
*/
public ScoredDocument[] runQuery(Node queryTree, int requested) throws Exception {
// my addition
queryTree = this.transformQuery(queryTree);
// System.out.println("runQuery: " + queryTree.toString());
// construct the query iterators
ScoreIterator iterator = (ScoreIterator) createIterator(queryTree);
// now there should be an iterator at the root of this tree
PriorityQueue<ScoredDocument> queue = new PriorityQueue<ScoredDocument>();
while (!iterator.isDone()) {
int document = iterator.nextCandidate();
int length = index.getLength(document);
double score = iterator.score(document, length);
if (queue.size() <= requested || queue.peek().score < score) {
ScoredDocument scoredDocument = new ScoredDocument(document, score);
queue.add(scoredDocument);
if (queue.size() > requested) {
queue.poll();
}
}
iterator.movePast(document);
}
return getArrayResults(queue);
}
public NodeType getNodeType(Node node) throws Exception {
NodeType nodeType = index.getNodeType(node);
if (nodeType == null) {
nodeType = featureFactory.getNodeType(node);
}
return nodeType;
}
public StructuredIterator createIterator(Node node) throws Exception {
ArrayList<StructuredIterator> internalIterators = new ArrayList<StructuredIterator>();
for (Node internalNode : node.getInternalNodes()) {
StructuredIterator internalIterator = createIterator(internalNode);
internalIterators.add(internalIterator);
}
StructuredIterator iterator = index.getIterator(node);
if (iterator == null) {
iterator = featureFactory.getIterator(node, internalIterators);
}
return iterator;
}
public void close() throws IOException {
index.close();
}
public String getDocumentName(int document) {
return index.getDocumentName(document);
}
