From 278dc0fc0415263c68ce9db5c7644765a37359e1 Mon Sep 17 00:00:00 2001
From: Michael McCandless <mikemccand@apache.org>
Date: Mon, 1 Dec 2008 18:50:45 +0000
Subject: [PATCH] LUCENE-1296: add protected method
 CachingWrapperFilter.docIdSetToCache

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@722174 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                            |  4 ++++
 .../src/java/org/apache/lucene/misc/ChainedFilter.java |  9 +++++++--
 .../java/org/apache/lucene/search/BooleanFilter.java   |  9 ++++++---
 .../org/apache/lucene/search/CachingWrapperFilter.java | 10 +++++++++-
 4 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 904d2a67ee7..e1c098be5ab 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -105,6 +105,10 @@ New features
     slower first-time usage due to populating the FieldCache.  (Tim
     Sturge via Mike McCandless)
 
+ 8. LUCENE-1296: add protected method CachingWrapperFilter.docIdSetToCache 
+    to allow subclasses to choose which DocIdSet implementation to use
+    (Paul Elschot via Mike McCandless)
+
 Optimizations
 
  1. LUCENE-1427: Fixed QueryWrapperFilter to not waste time computing
diff --git a/contrib/miscellaneous/src/java/org/apache/lucene/misc/ChainedFilter.java b/contrib/miscellaneous/src/java/org/apache/lucene/misc/ChainedFilter.java
index 097b9ccb052..0731c4bb241 100644
--- a/contrib/miscellaneous/src/java/org/apache/lucene/misc/ChainedFilter.java
+++ b/contrib/miscellaneous/src/java/org/apache/lucene/misc/ChainedFilter.java
@@ -176,8 +176,13 @@ public class ChainedFilter extends Filter
         }
         return result;
     }
-    
-    /** Provide a SortedVIntList when it is definitely smaller than an OpenBitSet */
+
+    // TODO: in 3.0, instead of removing this deprecated
+    // method, make it a no-op and mark it final
+    /** Provide a SortedVIntList when it is definitely
+     *  smaller than an OpenBitSet
+     *  @deprecated Either use CachingWrapperFilter, or
+     *  switch to a different DocIdSet implementation yourself. */
     protected DocIdSet finalResult(OpenBitSetDISI result, int maxDocs) {
         return (result.cardinality() < (maxDocs / 9))
               ? (DocIdSet) new SortedVIntList(result)
diff --git a/contrib/queries/src/java/org/apache/lucene/search/BooleanFilter.java b/contrib/queries/src/java/org/apache/lucene/search/BooleanFilter.java
index 552d1b2a539..c3c22f86255 100644
--- a/contrib/queries/src/java/org/apache/lucene/search/BooleanFilter.java
+++ b/contrib/queries/src/java/org/apache/lucene/search/BooleanFilter.java
@@ -19,11 +19,9 @@ package org.apache.lucene.search;
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.BitSet;
 
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.BooleanClause.Occur;
-import org.apache.lucene.util.DocIdBitSet;
 import org.apache.lucene.util.OpenBitSet;
 import org.apache.lucene.util.OpenBitSetDISI;
 import org.apache.lucene.util.SortedVIntList;
@@ -116,7 +114,12 @@ public class BooleanFilter extends Filter
     return emptyDocIdSet;
   }
 
-  /** Provide a SortedVIntList when it is definitely smaller than an OpenBitSet */
+  // TODO: in 3.0, instead of removing this deprecated
+  // method, make it a no-op and mark it final
+  /** Provide a SortedVIntList when it is definitely smaller
+   * than an OpenBitSet.
+   * @deprecated Either use CachingWrapperFilter, or
+   * switch to a different DocIdSet implementation yourself. */
   protected DocIdSet finalResult(OpenBitSetDISI result, int maxDocs) {
     return (result.cardinality() < (maxDocs / 9))
       ? (DocIdSet) new SortedVIntList(result)
diff --git a/src/java/org/apache/lucene/search/CachingWrapperFilter.java b/src/java/org/apache/lucene/search/CachingWrapperFilter.java
index 52d2b5d0f9c..4efeb40f35c 100644
--- a/src/java/org/apache/lucene/search/CachingWrapperFilter.java
+++ b/src/java/org/apache/lucene/search/CachingWrapperFilter.java
@@ -73,6 +73,14 @@ public class CachingWrapperFilter extends Filter {
 
     return bits;
   }
+
+  /** Provide the DocIdSet to be cached, using the DocIdSet provided
+   *  by the wrapped Filter.
+   *  This implementation returns the given DocIdSet.
+   */
+  protected DocIdSet docIdSetToCache(DocIdSet docIdSet, IndexReader reader) {
+    return docIdSet;
+  }
   
   public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
     if (cache == null) {
@@ -91,7 +99,7 @@ public class CachingWrapperFilter extends Filter {
         return new DocIdBitSet((BitSet) cached);
     }
 
-    final DocIdSet docIdSet = filter.getDocIdSet(reader);
+    final DocIdSet docIdSet = docIdSetToCache(filter.getDocIdSet(reader), reader);
 
     synchronized (cache) {  // update cache
       cache.put(reader, docIdSet);