From dfd94b518ac4bb933760987ad74f4ab3b63912e7 Mon Sep 17 00:00:00 2001
From: Adrien Grand <jpountz@apache.org>
Date: Wed, 25 Feb 2015 14:10:38 +0000
Subject: [PATCH] LUCENE-6227: Fix explanations of FILTER clauses.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1662218 13f79535-47bb-0310-9956-ffa450edef68
---
 .../apache/lucene/search/BooleanWeight.java   | 14 ++++++----
 .../lucene/search/TestSimpleExplanations.java | 28 +++++++++++++++++++
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/search/BooleanWeight.java b/lucene/core/src/java/org/apache/lucene/search/BooleanWeight.java
index 6ad7397fced..c5b99320698 100644
--- a/lucene/core/src/java/org/apache/lucene/search/BooleanWeight.java
+++ b/lucene/core/src/java/org/apache/lucene/search/BooleanWeight.java
@@ -110,6 +110,7 @@ public class BooleanWeight extends Weight {
     int coord = 0;
     float sum = 0.0f;
     boolean fail = false;
+    int matchCount = 0;
     int shouldMatchCount = 0;
     Iterator<BooleanClause> cIter = query.clauses().iterator();
     for (Iterator<Weight> wIter = weights.iterator(); wIter.hasNext();) {
@@ -130,10 +131,10 @@ public class BooleanWeight extends Weight {
           sum += e.getValue();
           coord++;
         } else if (c.isRequired()) {
-          Explanation r =
-              new Explanation(0.0f, "match on required clause (" + c.getQuery().toString() + ")");
-            r.addDetail(e);
-            sumExpl.addDetail(r);
+          Explanation r = new Explanation(0f, "match on required clause, product of:");
+          r.addDetail(new Explanation(0f, Occur.FILTER + " clause"));
+          r.addDetail(e);
+          sumExpl.addDetail(r);
         } else if (c.isProhibited()) {
           Explanation r =
             new Explanation(0.0f, "match on prohibited clause (" + c.getQuery().toString() + ")");
@@ -141,6 +142,9 @@ public class BooleanWeight extends Weight {
           sumExpl.addDetail(r);
           fail = true;
         }
+        if (!c.isProhibited()) {
+          matchCount++;
+        }
         if (c.getOccur() == Occur.SHOULD) {
           shouldMatchCount++;
         }
@@ -165,7 +169,7 @@ public class BooleanWeight extends Weight {
       return sumExpl;
     }
     
-    sumExpl.setMatch(0 < coord ? Boolean.TRUE : Boolean.FALSE);
+    sumExpl.setMatch(0 < matchCount);
     sumExpl.setValue(sum);
     
     final float coordFactor = disableCoord ? 1.0f : coord(coord, maxCoord);
diff --git a/lucene/core/src/test/org/apache/lucene/search/TestSimpleExplanations.java b/lucene/core/src/test/org/apache/lucene/search/TestSimpleExplanations.java
index afbabc2d242..2f0cb26392c 100644
--- a/lucene/core/src/test/org/apache/lucene/search/TestSimpleExplanations.java
+++ b/lucene/core/src/test/org/apache/lucene/search/TestSimpleExplanations.java
@@ -483,6 +483,34 @@ public class TestSimpleExplanations extends BaseExplanationTestCase {
     
   }
 
+  public void testBQ23() throws Exception {
+    BooleanQuery query = new BooleanQuery();
+    query.add(new TermQuery(new Term(FIELD, "w1")), BooleanClause.Occur.FILTER);
+    query.add(new TermQuery(new Term(FIELD, "w2")), BooleanClause.Occur.FILTER);
+    qtest(query, new int[] { 0,1,2,3 });
+  }
+
+  public void testBQ24() throws Exception {
+    BooleanQuery query = new BooleanQuery();
+    query.add(new TermQuery(new Term(FIELD, "w1")), BooleanClause.Occur.FILTER);
+    query.add(new TermQuery(new Term(FIELD, "w2")), BooleanClause.Occur.SHOULD);
+    qtest(query, new int[] { 0,1,2,3 });
+  }
+
+  public void testBQ25() throws Exception {
+    BooleanQuery query = new BooleanQuery();
+    query.add(new TermQuery(new Term(FIELD, "w1")), BooleanClause.Occur.FILTER);
+    query.add(new TermQuery(new Term(FIELD, "w2")), BooleanClause.Occur.MUST);
+    qtest(query, new int[] { 0,1,2,3 });
+  }
+
+  public void testBQ26() throws Exception {
+    BooleanQuery query = new BooleanQuery();
+    query.add(new TermQuery(new Term(FIELD, "w1")), BooleanClause.Occur.FILTER);
+    query.add(new TermQuery(new Term(FIELD, "xx")), BooleanClause.Occur.MUST_NOT);
+    qtest(query, new int[] { 0,1 });
+  }
+
   /* BQ of TQ: using alt so some fields have zero boost and some don't */
   
   public void testMultiFieldBQ1() throws Exception {