LUCENE-6290: Make the filter -> query migration less trappy.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1662203 13f79535-47bb-0310-9956-ffa450edef68

lucene/CHANGES.txt

@@ -108,6 +108,10 @@ Optimizations
   in order to advance doc IDs, which takes advantage of the cost() API.
   (Adrien Grand)
 
+* LUCENE-6290: QueryWrapperFilter propagates approximations and FilteredQuery
+  rewrites to a BooleanQuery when the filter is a QueryWrapperFilter in order
+  to leverage approximations. (Adrien Grand)
+
 API Changes
 
 * LUCENE-6204, LUCENE-6208: Simplify CompoundFormat: remove files()

lucene/core/src/java/org/apache/lucene/search/FilteredQuery.java

@@ -25,6 +25,7 @@ import java.util.Set;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.ToStringUtils;
 
@@ -301,6 +302,16 @@ public class FilteredQuery extends Query {
    * it returns a new {@code FilteredQuery} wrapping the rewritten query. */
   @Override
   public Query rewrite(IndexReader reader) throws IOException {
+    if (filter instanceof QueryWrapperFilter) {
+      // In that case the filter does not implement random-access anyway so
+      // we want to take advantage of approximations
+      BooleanQuery rewritten = new BooleanQuery();
+      rewritten.add(query, Occur.MUST);
+      rewritten.add(((QueryWrapperFilter) filter).getQuery(), Occur.FILTER);
+      rewritten.setBoost(getBoost());
+      return rewritten;
+    }
+
     final Query queryRewritten = query.rewrite(reader);
     
     if (queryRewritten != query) {

lucene/core/src/java/org/apache/lucene/search/QueryWrapperFilter.java

@@ -17,12 +17,12 @@ package org.apache.lucene.search;
  * limitations under the License.
  */
 
-import org.apache.lucene.index.PostingsEnum;
+import java.io.IOException;
+
+import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.util.Bits;
 
-import java.io.IOException;
-
 /** 
  * Constrains search results to only match those which also match a provided
  * query.  
@@ -44,6 +44,13 @@ public class QueryWrapperFilter extends Filter {
     this.query = query;
   }
   
+  @Override
+  public Query rewrite(IndexReader reader) throws IOException {
+    ConstantScoreQuery rewritten = new ConstantScoreQuery(query);
+    rewritten.setBoost(0);
+    return rewritten;
+  }
+  
   /** returns the inner Query */
   public final Query getQuery() {
     return query;

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

@@ -25,6 +25,8 @@ import org.apache.lucene.analysis.MockAnalyzer;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.SortedDocValuesField;
+import org.apache.lucene.document.StringField;
+import org.apache.lucene.document.Field.Store;
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.PostingsEnum;
@@ -587,6 +589,51 @@ public class TestFilteredQuery extends LuceneTestCase {
     assertEquals(totalDocsWithZero, search.totalHits);
     IOUtils.close(reader, directory);
   }
+
+  public void testPreservesScores() throws IOException {
+    Directory dir = newDirectory();
+    RandomIndexWriter writer = new RandomIndexWriter(random(), dir);
+    Document doc = new Document();
+    doc.add(new StringField("foo", "bar", Store.NO));
+    writer.addDocument(doc);
+    writer.commit();
+    final IndexReader reader = writer.getReader();
+    writer.close();
+    final IndexSearcher searcher = new IndexSearcher(reader);
+    final Query query = new TermQuery(new Term("foo", "bar"));
+    query.setBoost(random().nextFloat());
+    FilteredQuery fq = new FilteredQuery(query, new Filter() {
+      @Override
+      public DocIdSet getDocIdSet(LeafReaderContext context, Bits acceptDocs)
+          throws IOException {
+        return new DocIdSet() {
+          
+          @Override
+          public long ramBytesUsed() {
+            return 0;
+          }
+          
+          @Override
+          public DocIdSetIterator iterator() throws IOException {
+            return DocIdSetIterator.all(context.reader().maxDoc());
+          }
+        };
+      }
+      @Override
+      public String toString(String field) {
+        return "dummy";
+      }
+    });
+    assertEquals(searcher.search(query, 1).scoreDocs[0].score, searcher.search(fq, 1).scoreDocs[0].score, 0f);
+    fq.setBoost(random().nextFloat());
+    // QueryWrapperFilter has special rewrite rules
+    FilteredQuery fq2 = new FilteredQuery(query, new QueryWrapperFilter(new MatchAllDocsQuery()));
+    fq2.setBoost(fq.getBoost());
+    fq2.setBoost(42);
+    assertEquals(searcher.search(fq, 1).scoreDocs[0].score, searcher.search(fq2, 1).scoreDocs[0].score, 10e-5);
+    reader.close();
+    dir.close();
+  }
 }
 
 

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

@@ -16,11 +16,14 @@ package org.apache.lucene.search;
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+import java.io.IOException;
 import java.util.HashSet;
 import java.util.Set;
 
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
+import org.apache.lucene.document.Field.Store;
+import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.RandomIndexWriter;
 import org.apache.lucene.index.Term;
@@ -148,4 +151,40 @@ public class TestQueryWrapperFilter extends LuceneTestCase {
     reader.close();
     dir.close();
   }
+
+  public void testScore() throws IOException {
+    Directory dir = newDirectory();
+    RandomIndexWriter writer = new RandomIndexWriter(random(), dir);
+    Document doc = new Document();
+    doc.add(new StringField("foo", "bar", Store.NO));
+    writer.addDocument(doc);
+    writer.commit();
+    final IndexReader reader = writer.getReader();
+    writer.close();
+    final IndexSearcher searcher = new IndexSearcher(reader);
+    final Query query = new QueryWrapperFilter(new TermQuery(new Term("foo", "bar")));
+    final TopDocs topDocs = searcher.search(query, 1);
+    assertEquals(1, topDocs.totalHits);
+    assertEquals(0f, topDocs.scoreDocs[0].score, 0f);
+    reader.close();
+    dir.close();
+  }
+
+  public void testQueryWrapperFilterPropagatesApproximations() throws IOException {
+    Directory dir = newDirectory();
+    RandomIndexWriter writer = new RandomIndexWriter(random(), dir);
+    Document doc = new Document();
+    doc.add(new StringField("foo", "bar", Store.NO));
+    writer.addDocument(doc);
+    writer.commit();
+    final IndexReader reader = writer.getReader();
+    writer.close();
+    final IndexSearcher searcher = new IndexSearcher(reader);
+    final Query query = new QueryWrapperFilter(new RandomApproximationQuery(new TermQuery(new Term("foo", "bar")), random()));
+    final Weight weight = searcher.createNormalizedWeight(query, random().nextBoolean());
+    final Scorer scorer = weight.scorer(reader.leaves().get(0), null);
+    assertNotNull(scorer.asTwoPhaseIterator());
+    reader.close();
+    dir.close();
+  }
 }

lucene/join/src/test/org/apache/lucene/search/join/TestBlockJoinValidation.java

@@ -30,6 +30,7 @@ import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
+import org.apache.lucene.search.CachingWrapperFilter;
 import org.apache.lucene.search.Filter;
 import org.apache.lucene.search.FilteredQuery;
 import org.apache.lucene.search.IndexSearcher;
@@ -119,7 +120,7 @@ public class TestBlockJoinValidation extends LuceneTestCase {
     Query parentQueryWithRandomChild = createParentQuery();
 
     ToChildBlockJoinQuery blockJoinQuery = new ToChildBlockJoinQuery(parentQueryWithRandomChild, parentsFilter);
-    Filter childFilter = new QueryWrapperFilter(new TermQuery(new Term("common_field", "1")));
+    Filter childFilter = new CachingWrapperFilter(new QueryWrapperFilter(new TermQuery(new Term("common_field", "1"))));
     thrown.expect(IllegalStateException.class);
     thrown.expectMessage(ToChildBlockJoinQuery.ILLEGAL_ADVANCE_ON_PARENT);
     indexSearcher.search(new FilteredQuery(blockJoinQuery, childFilter), 1);