--- /dev/null
+package org.apache.lucene.facet.search.sampling;
+
+import java.io.IOException;
+
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.index.TermDocs;
+
+import org.apache.lucene.facet.search.DrillDown;
+import org.apache.lucene.facet.search.ScoredDocIDs;
+import org.apache.lucene.facet.search.ScoredDocIDsIterator;
+import org.apache.lucene.facet.search.params.FacetSearchParams;
+import org.apache.lucene.facet.search.results.FacetResult;
+import org.apache.lucene.facet.search.results.FacetResultNode;
+import org.apache.lucene.facet.taxonomy.CategoryPath;
+import org.apache.lucene.facet.taxonomy.TaxonomyReader;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Fix sampling results by counting the intersection between two lists: a
+ * TermDocs (list of documents in a certain category) and a DocIdSetIterator
+ * (list of documents matching the query).
+ *
+ *
+ * @lucene.experimental
+ */
+// TODO (Facet): implement also an estimated fixing by ratio (taking into
+// account "translation" of counts!)
+class TakmiSampleFixer implements SampleFixer {
+
+ private TaxonomyReader taxonomyReader;
+ private IndexReader indexReader;
+ private FacetSearchParams searchParams;
+
+ public TakmiSampleFixer(IndexReader indexReader,
+ TaxonomyReader taxonomyReader, FacetSearchParams searchParams) {
+ this.indexReader = indexReader;
+ this.taxonomyReader = taxonomyReader;
+ this.searchParams = searchParams;
+ }
+
+ public void fixResult(ScoredDocIDs origDocIds, FacetResult fres)
+ throws IOException {
+ FacetResultNode topRes = fres.getFacetResultNode();
+ fixResultNode(topRes, origDocIds);
+ }
+
+ /**
+ * Fix result node count, and, recursively, fix all its children
+ *
+ * @param facetResNode
+ * result node to be fixed
+ * @param docIds
+ * docids in effect
+ * @throws IOException
+ */
+ private void fixResultNode(FacetResultNode facetResNode, ScoredDocIDs docIds)
+ throws IOException {
+ recount(facetResNode, docIds);
+ for (FacetResultNode frn : facetResNode.getSubResults()) {
+ fixResultNode(frn, docIds);
+ }
+ }
+
+ /**
+ * Internal utility: recount for a facet result node
+ *
+ * @param fresNode
+ * result node to be recounted
+ * @param docIds
+ * full set of matching documents.
+ * @throws IOException
+ */
+ private void recount(FacetResultNode fresNode, ScoredDocIDs docIds)
+ throws IOException {
+ // TODO (Facet): change from void to return the new, smaller docSet, and use
+ // that for the children, as this will make their intersection ops faster.
+ // can do this only when the new set is "sufficiently" smaller.
+
+ /* We need the category's path name in order to do its recounting.
+ * If it is missing, because the option to label only part of the
+ * facet results was exercise, we need to calculate them anyway, so
+ * in essence sampling with recounting spends some extra cycles for
+ * labeling results for which labels are not required. */
+ CategoryPath catPath = fresNode.getLabel(taxonomyReader); // force labeling
+
+ Term drillDownTerm = DrillDown.term(searchParams, catPath);
+ int updatedCount = countIntersection(indexReader.termDocs(drillDownTerm),
+ docIds.iterator());
+
+ fresNode.setValue(updatedCount);
+ }
+
+ /**
+ * Count the size of the intersection between two lists: a TermDocs (list of
+ * documents in a certain category) and a DocIdSetIterator (list of documents
+ * matching a query).
+ */
+ private static int countIntersection(TermDocs p1, ScoredDocIDsIterator p2)
+ throws IOException {
+ // The documentation of of both TermDocs and DocIdSetIterator claim
+ // that we must do next() before doc(). So we do, and if one of the
+ // lists is empty, obviously return 0;
+ if (!p1.next()) {
+ return 0;
+ }
+ if (!p2.next()) {
+ return 0;
+ }
+
+ int d1 = p1.doc();
+ int d2 = p2.getDocID();
+
+ int count = 0;
+ for (;;) {
+ if (d1 == d2) {
+ ++count;
+ if (!p1.next()) {
+ break; // end of list 1, nothing more in intersection
+ }
+ d1 = p1.doc();
+ if (!advance(p2, d1)) {
+ break; // end of list 2, nothing more in intersection
+ }
+ d2 = p2.getDocID();
+ } else if (d1 < d2) {
+ if (!p1.skipTo(d2)) {
+ break; // end of list 1, nothing more in intersection
+ }
+ d1 = p1.doc();
+ } else /* d1>d2 */ {
+ if (!advance(p2, d1)) {
+ break; // end of list 2, nothing more in intersection
+ }
+ d2 = p2.getDocID();
+ }
+ }
+ return count;
+ }
+
+ /**
+ * utility: advance the iterator until finding (or exceeding) specific
+ * document
+ *
+ * @param iterator
+ * iterator being advanced
+ * @param targetDoc
+ * target of advancing
+ * @return false if iterator exhausted, true otherwise.
+ */
+ private static boolean advance(ScoredDocIDsIterator iterator, int targetDoc) {
+ while (iterator.next()) {
+ if (iterator.getDocID() >= targetDoc) {
+ return true; // target reached
+ }
+ }
+ return false; // exhausted
+ }
+}
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fnp / pylucene.git / blobdiff