--- /dev/null
+package org.apache.lucene.facet.search.sampling;
+
+import java.io.IOException;
+
+import org.apache.lucene.facet.search.ScoredDocIDs;
+import org.apache.lucene.facet.search.results.FacetResult;
+
+/**
+ * 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.
+ */
+
+/**
+ * Fixer of sample facet accumulation results
+ *
+ * @lucene.experimental
+ */
+public interface SampleFixer {
+
+ /**
+ * Alter the input result, fixing it to account for the sampling. This
+ * implementation can compute accurate or estimated counts for the sampled facets.
+ * For example, a faster correction could just multiply by a compensating factor.
+ *
+ * @param origDocIds
+ * full set of matching documents.
+ * @param fres
+ * sample result to be fixed.
+ * @throws IOException
+ */
+ public void fixResult(ScoredDocIDs origDocIds, FacetResult fres) throws IOException;
+}
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