add RawTFSimilarity class (#13749)

lucene/core/src/java/org/apache/lucene/search/similarities/RawTFSimilarity.java

@@ -0,0 +1,45 @@
+/*
+ * 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.
+ */
+package org.apache.lucene.search.similarities;
+
+import org.apache.lucene.search.CollectionStatistics;
+import org.apache.lucene.search.TermStatistics;
+
+/** Similarity that returns the raw TF as score. */
+public class RawTFSimilarity extends Similarity {
+
+  /** Default constructor: parameter-free */
+  public RawTFSimilarity() {
+    super();
+  }
+
+  /** Primary constructor. */
+  public RawTFSimilarity(boolean discountOverlaps) {
+    super(discountOverlaps);
+  }
+
+  @Override
+  public SimScorer scorer(
+      float boost, CollectionStatistics collectionStats, TermStatistics... termStats) {
+    return new SimScorer() {
+      @Override
+      public float score(float freq, long norm) {
+        return boost * freq;
+      }
+    };
+  }
+}

lucene/core/src/test/org/apache/lucene/search/TestBooleanQueryVisitSubscorers.java

@@ -29,14 +29,13 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field.Store;
 import org.apache.lucene.document.TextField;
-import org.apache.lucene.index.FieldInvertState;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.similarities.ClassicSimilarity;
-import org.apache.lucene.search.similarities.Similarity;
+import org.apache.lucene.search.similarities.RawTFSimilarity;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.tests.index.RandomIndexWriter;
@@ -75,7 +74,7 @@ public class TestBooleanQueryVisitSubscorers extends LuceneTestCase {
     searcher = newSearcher(reader, true, false);
     searcher.setSimilarity(new ClassicSimilarity());
     scorerSearcher = new ScorerIndexSearcher(reader);
-    scorerSearcher.setSimilarity(new CountingSimilarity());
+    scorerSearcher.setSimilarity(new RawTFSimilarity());
   }
 
   @Override
@@ -345,24 +344,4 @@ public class TestBooleanQueryVisitSubscorers extends LuceneTestCase {
       return builder;
     }
   }
-
-  // Similarity that just returns the frequency as the score
-  private static class CountingSimilarity extends Similarity {
-
-    @Override
-    public long computeNorm(FieldInvertState state) {
-      return 1;
-    }
-
-    @Override
-    public SimScorer scorer(
-        float boost, CollectionStatistics collectionStats, TermStatistics... termStats) {
-      return new SimScorer() {
-        @Override
-        public float score(float freq, long norm) {
-          return freq;
-        }
-      };
-    }
-  }
 }

lucene/core/src/test/org/apache/lucene/search/TestConjunctions.java

@@ -29,12 +29,11 @@ import org.apache.lucene.document.Field.Store;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.DirectoryReader;
-import org.apache.lucene.index.FieldInvertState;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.similarities.Similarity;
+import org.apache.lucene.search.similarities.RawTFSimilarity;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.tests.analysis.MockAnalyzer;
 import org.apache.lucene.tests.index.RandomIndexWriter;
@@ -67,7 +66,7 @@ public class TestConjunctions extends LuceneTestCase {
     reader = writer.getReader();
     writer.close();
     searcher = newSearcher(reader);
-    searcher.setSimilarity(new TFSimilarity());
+    searcher.setSimilarity(new RawTFSimilarity());
   }
 
   static Document doc(String v1, String v2) {
@@ -93,26 +92,6 @@ public class TestConjunctions extends LuceneTestCase {
     super.tearDown();
   }
 
-  // Similarity that returns the TF as score
-  private static class TFSimilarity extends Similarity {
-
-    @Override
-    public long computeNorm(FieldInvertState state) {
-      return 1; // we dont care
-    }
-
-    @Override
-    public SimScorer scorer(
-        float boost, CollectionStatistics collectionStats, TermStatistics... termStats) {
-      return new SimScorer() {
-        @Override
-        public float score(float freq, long norm) {
-          return freq;
-        }
-      };
-    }
-  }
-
   public void testScorerGetChildren() throws Exception {
     Directory dir = newDirectory();
     IndexWriter w = new IndexWriter(dir, newIndexWriterConfig());

lucene/core/src/test/org/apache/lucene/search/similarities/TestRawTFSimilarity.java

@@ -0,0 +1,103 @@
+/*
+ * 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.
+ */
+package org.apache.lucene.search.similarities;
+
+import java.io.IOException;
+import java.util.Random;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.index.DirectoryReader;
+import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.search.BoostQuery;
+import org.apache.lucene.search.IndexSearcher;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.TermQuery;
+import org.apache.lucene.search.TopDocs;
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.tests.search.similarities.BaseSimilarityTestCase;
+import org.apache.lucene.tests.util.LuceneTestCase;
+import org.apache.lucene.util.IOUtils;
+
+public class TestRawTFSimilarity extends BaseSimilarityTestCase {
+
+  private Directory directory;
+  private IndexReader indexReader;
+  private IndexSearcher indexSearcher;
+
+  @Override
+  protected Similarity getSimilarity(Random random) {
+    return new RawTFSimilarity();
+  }
+
+  @Override
+  public void setUp() throws Exception {
+    super.setUp();
+    directory = newDirectory();
+    try (IndexWriter indexWriter = new IndexWriter(directory, newIndexWriterConfig())) {
+      final Document document1 = new Document();
+      final Document document2 = new Document();
+      final Document document3 = new Document();
+      document1.add(LuceneTestCase.newTextField("test", "one", Field.Store.YES));
+      document2.add(LuceneTestCase.newTextField("test", "two two", Field.Store.YES));
+      document3.add(LuceneTestCase.newTextField("test", "three three three", Field.Store.YES));
+      indexWriter.addDocument(document1);
+      indexWriter.addDocument(document2);
+      indexWriter.addDocument(document3);
+      indexWriter.commit();
+    }
+    indexReader = DirectoryReader.open(directory);
+    indexSearcher = newSearcher(indexReader);
+    indexSearcher.setSimilarity(new RawTFSimilarity());
+  }
+
+  @Override
+  public void tearDown() throws Exception {
+    IOUtils.close(indexReader, directory);
+    super.tearDown();
+  }
+
+  public void testOne() throws IOException {
+    implTest("one", 1f);
+  }
+
+  public void testTwo() throws IOException {
+    implTest("two", 2f);
+  }
+
+  public void testThree() throws IOException {
+    implTest("three", 3f);
+  }
+
+  private void implTest(String text, float expectedScore) throws IOException {
+    Query query = new TermQuery(new Term("test", text));
+    TopDocs topDocs = indexSearcher.search(query, 1);
+    assertEquals(1, topDocs.totalHits.value());
+    assertEquals(1, topDocs.scoreDocs.length);
+    assertEquals(expectedScore, topDocs.scoreDocs[0].score, 0.0);
+  }
+
+  public void testBoostQuery() throws IOException {
+    Query query = new TermQuery(new Term("test", "three"));
+    float boost = 14f;
+    TopDocs topDocs = indexSearcher.search(new BoostQuery(query, boost), 1);
+    assertEquals(1, topDocs.totalHits.value());
+    assertEquals(1, topDocs.scoreDocs.length);
+    assertEquals(42f, topDocs.scoreDocs[0].score, 0.0);
+  }
+}