Index: src/java/org/apache/lucene/search/QueryFilter.java
===================================================================
--- src/java/org/apache/lucene/search/QueryFilter.java	(revision 525635)
+++ src/java/org/apache/lucene/search/QueryFilter.java	(working copy)
@@ -18,14 +18,14 @@
  */
 
 import java.io.IOException;
-import java.util.WeakHashMap;
 import java.util.BitSet;
+
 import org.apache.lucene.index.IndexReader;
 
 /** Constrains search results to only match those which also match a provided
- * query.  Results are cached, so that searches after the first on the same
- * index using this filter are much faster.
- *
+ * query.  Results are not cached.  To cache the filter bits wrap the QueryFilter
+ * in the {@link org.apache.lucene.search.CachingWrapperFilter}.
+ * 
  * <p> This could be used, for example, with a {@link RangeQuery} on a suitably
  * formatted date field to implement date filtering.  One could re-use a single
  * QueryFilter that matches, e.g., only documents modified within the last
@@ -36,7 +36,6 @@
  */
 public class QueryFilter extends Filter {
   private Query query;
-  private transient WeakHashMap cache = null;
 
   /** Constructs a filter which only matches documents matching
    * <code>query</code>.
@@ -47,17 +46,6 @@
 
   public BitSet bits(IndexReader reader) throws IOException {
 
-    if (cache == null) {
-      cache = new WeakHashMap();
-    }
-
-    synchronized (cache) {  // check cache
-      BitSet cached = (BitSet) cache.get(reader);
-      if (cached != null) {
-        return cached;
-      }
-    }
-
     final BitSet bits = new BitSet(reader.maxDoc());
 
     new IndexSearcher(reader).search(query, new HitCollector() {
@@ -66,10 +54,6 @@
       }
     });
 
-    synchronized (cache) {  // update cache
-      cache.put(reader, bits);
-    }
-
     return bits;
   }