Index: src/java/org/apache/lucene/search/ConstantScoreQuery.java
===================================================================
--- src/java/org/apache/lucene/search/ConstantScoreQuery.java	(revision 733441)
+++ src/java/org/apache/lucene/search/ConstantScoreQuery.java	(working copy)
@@ -20,13 +20,12 @@
 import org.apache.lucene.index.IndexReader;
 
 import java.io.IOException;
-import java.util.Set;
 
 /**
  * A query that wraps a filter and simply returns a constant score equal to the
  * query boost for every document in the filter.
  *
- *
+ * @deprecated Use {@link Filter} directly as {@link Query}.
  * @version $Id$
  */
 public class ConstantScoreQuery extends Query {
@@ -40,114 +39,20 @@
   public Filter getFilter() {
     return filter;
   }
+  
+  public void setBoost(float boost) {
+    super.setBoost(boost);
+    filter.setBoost(getBoost());
+  }
 
   public Query rewrite(IndexReader reader) throws IOException {
-    return this;
+    return filter.rewrite(reader);
   }
 
-  public void extractTerms(Set terms) {
-    // OK to not add any terms when used for MultiSearcher,
-    // but may not be OK for highlighting
-  }
-
-  protected class ConstantWeight implements Weight {
-    private Similarity similarity;
-    private float queryNorm;
-    private float queryWeight;
-
-    public ConstantWeight(Searcher searcher) {
-      this.similarity = getSimilarity(searcher);
-    }
-
-    public Query getQuery() {
-      return ConstantScoreQuery.this;
-    }
-
-    public float getValue() {
-      return queryWeight;
-    }
-
-    public float sumOfSquaredWeights() throws IOException {
-      queryWeight = getBoost();
-      return queryWeight * queryWeight;
-    }
-
-    public void normalize(float norm) {
-      this.queryNorm = norm;
-      queryWeight *= this.queryNorm;
-    }
-
-    public Scorer scorer(IndexReader reader) throws IOException {
-      return new ConstantScorer(similarity, reader, this);
-    }
-
-    public Explanation explain(IndexReader reader, int doc) throws IOException {
-
-      ConstantScorer cs = (ConstantScorer)scorer(reader);
-      boolean exists = cs.docIdSetIterator.skipTo(doc) && (cs.docIdSetIterator.doc() == doc);
-
-      ComplexExplanation result = new ComplexExplanation();
-
-      if (exists) {
-        result.setDescription("ConstantScoreQuery(" + filter
-        + "), product of:");
-        result.setValue(queryWeight);
-        result.setMatch(Boolean.TRUE);
-        result.addDetail(new Explanation(getBoost(), "boost"));
-        result.addDetail(new Explanation(queryNorm,"queryNorm"));
-      } else {
-        result.setDescription("ConstantScoreQuery(" + filter
-        + ") doesn't match id " + doc);
-        result.setValue(0);
-        result.setMatch(Boolean.FALSE);
-      }
-      return result;
-    }
-  }
-
-  protected class ConstantScorer extends Scorer {
-    final DocIdSetIterator docIdSetIterator;
-    final float theScore;
-    int doc=-1;
-
-    public ConstantScorer(Similarity similarity, IndexReader reader, Weight w) throws IOException {
-      super(similarity);
-      theScore = w.getValue();
-      docIdSetIterator = filter.getDocIdSet(reader).iterator();
-    }
-
-    public boolean next() throws IOException {
-      return docIdSetIterator.next();
-    }
-
-    public int doc() {
-      return docIdSetIterator.doc();
-    }
-
-    public float score() throws IOException {
-      return theScore;
-    }
-
-    public boolean skipTo(int target) throws IOException {
-      return docIdSetIterator.skipTo(target);
-    }
-
-    public Explanation explain(int doc) throws IOException {
-      throw new UnsupportedOperationException();
-    }
-  }
-
-
-  protected Weight createWeight(Searcher searcher) {
-    return new ConstantScoreQuery.ConstantWeight(searcher);
-  }
-
-
   /** Prints a user-readable version of this query. */
   public String toString(String field)
   {
-    return "ConstantScore(" + filter.toString()
-      + (getBoost()==1.0 ? ")" : "^" + getBoost());
+    return filter.toString(field);
   }
 
   /** Returns true if <code>o</code> is equal to this. */
@@ -155,13 +60,12 @@
     if (this == o) return true;
     if (!(o instanceof ConstantScoreQuery)) return false;
     ConstantScoreQuery other = (ConstantScoreQuery)o;
-    return this.getBoost()==other.getBoost() && filter.equals(other.filter);
+    return this.filter.equals(other.filter);
   }
 
   /** Returns a hash code value for this object. */
   public int hashCode() {
-    // Simple add is OK since no existing filter hashcode has a float component.
-    return filter.hashCode() + Float.floatToIntBits(getBoost());
+    return filter.hashCode();
   }
 
 }
Index: src/java/org/apache/lucene/search/Filter.java
===================================================================
--- src/java/org/apache/lucene/search/Filter.java	(revision 733441)
+++ src/java/org/apache/lucene/search/Filter.java	(working copy)
@@ -17,8 +17,12 @@
  * limitations under the License.
  */
 
+import java.io.IOException;
+import java.util.Set;
 import java.util.BitSet;
 import java.io.IOException;
+import java.io.Serializable;
+
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.util.DocIdBitSet;
 
@@ -30,14 +34,14 @@
  *  All implementing classes must therefore implement {@link #getDocIdSet(IndexReader)}
  *  in order to work with Lucene 3.0.
  */
-public abstract class Filter implements java.io.Serializable {
+public abstract class Filter extends Query implements Serializable {
   /**
    * @return A BitSet with true for documents which should be permitted in
    * search results, and false for those that should not.
    * @deprecated Use {@link #getDocIdSet(IndexReader)} instead.
    */
   public BitSet bits(IndexReader reader) throws IOException {
-    return null;
+    throw new UnsupportedOperationException();
   }
 	
   /**
@@ -48,4 +52,120 @@
   public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
     return new DocIdBitSet(bits(reader));
   }
+
+  public Query rewrite(IndexReader reader) throws IOException {
+    return this;
+  }
+
+  /** Prints a query to a string. */
+  public String toString() {
+    // revert to default toString(), because of infinite loop
+    return getClass().getName() + '@' + Integer.toHexString(hashCode());
+  }
+
+  /** Prints a user-readable version of this query. */
+  public String toString(String field)
+  {
+    // this method currently maps to the generic
+    // toString() method, because toString(field) is
+    // abstract in Query, but does not exist in current
+    // Filter!
+    return toString();
+  }
+
+  public void extractTerms(Set terms) {
+    // OK to not add any terms when used for MultiSearcher,
+    // but may not be OK for highlighting
+  }
+
+  protected class ConstantWeight implements Weight {
+    private Similarity similarity;
+    private float queryNorm;
+    private float queryWeight;
+
+    public ConstantWeight(Searcher searcher) {
+      this.similarity = getSimilarity(searcher);
+    }
+
+    public Query getQuery() {
+      return Filter.this;
+    }
+
+    public float getValue() {
+      return queryWeight;
+    }
+
+    public float sumOfSquaredWeights() throws IOException {
+      queryWeight = getBoost();
+      return queryWeight * queryWeight;
+    }
+
+    public void normalize(float norm) {
+      this.queryNorm = norm;
+      queryWeight *= this.queryNorm;
+    }
+
+    public Scorer scorer(IndexReader reader) throws IOException {
+      return new ConstantScorer(similarity, reader, this);
+    }
+
+    public Explanation explain(IndexReader reader, int doc) throws IOException {
+
+      ConstantScorer cs = (ConstantScorer)scorer(reader);
+      boolean exists = cs.docIdSetIterator.skipTo(doc) && (cs.docIdSetIterator.doc() == doc);
+
+      ComplexExplanation result = new ComplexExplanation();
+
+      if (exists) {
+        result.setDescription(getQuery() + ", product of:");
+        result.setValue(queryWeight);
+        result.setMatch(Boolean.TRUE);
+        result.addDetail(new Explanation(getBoost(), "boost"));
+        result.addDetail(new Explanation(queryNorm,"queryNorm"));
+      } else {
+        result.setDescription(getQuery() + " doesn't match id " + doc);
+        result.setValue(0);
+        result.setMatch(Boolean.FALSE);
+      }
+      return result;
+    }
+  }
+
+  protected class ConstantScorer extends Scorer {
+    final DocIdSetIterator docIdSetIterator;
+    final float theScore;
+    int doc=-1;
+
+    public ConstantScorer(Similarity similarity, IndexReader reader, Weight w) throws IOException {
+      super(similarity);
+      theScore = w.getValue();
+      docIdSetIterator = Filter.this.getDocIdSet(reader).iterator();
+    }
+
+    public boolean next() throws IOException {
+      return docIdSetIterator.next();
+    }
+
+    public int doc() {
+      return docIdSetIterator.doc();
+    }
+
+    public float score() throws IOException {
+      return theScore;
+    }
+
+    public boolean skipTo(int target) throws IOException {
+      return docIdSetIterator.skipTo(target);
+    }
+
+    public Explanation explain(int doc) throws IOException {
+      throw new UnsupportedOperationException();
+    }
+  }
+
+
+  protected Weight createWeight(Searcher searcher) {
+    return new ConstantWeight(searcher);
+  }
+
 }