Index: src/test/org/apache/lucene/analysis/TestReverseStringFilter.java
===================================================================
--- src/test/org/apache/lucene/analysis/TestReverseStringFilter.java	(revision 0)
+++ src/test/org/apache/lucene/analysis/TestReverseStringFilter.java	(revision 0)
@@ -0,0 +1,20 @@
+package org.apache.lucene.analysis;
+
+import java.io.StringReader;
+
+import org.apache.lucene.util.LuceneTestCase;
+
+public class TestReverseStringFilter extends LuceneTestCase {
+  public void testFilter() throws Exception {
+    TokenStream stream = new WhitespaceTokenizer(
+        new StringReader("Do have a nice day"));     // 1-4 length string
+    ReverseStringFilter filter = new ReverseStringFilter(stream);
+    final Token reusableToken = new Token();
+    assertEquals("oD", filter.next(reusableToken).term());
+    assertEquals("evah", filter.next(reusableToken).term());
+    assertEquals("a", filter.next(reusableToken).term());
+    assertEquals("ecin", filter.next(reusableToken).term());
+    assertEquals("yad", filter.next(reusableToken).term());
+    assertNull(filter.next(reusableToken));
+  }
+}

Property changes on: src\test\org\apache\lucene\analysis\TestReverseStringFilter.java
___________________________________________________________________
Added: svn:keywords
   + Author Date Id Revision
Added: svn:eol-style
   + native

Index: src/java/org/apache/lucene/analysis/ReverseStringFilter.java
===================================================================
--- src/java/org/apache/lucene/analysis/ReverseStringFilter.java	(revision 0)
+++ src/java/org/apache/lucene/analysis/ReverseStringFilter.java	(revision 0)
@@ -0,0 +1,53 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.lucene.analysis;
+
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Token;
+
+import java.io.IOException;
+
+/**
+ * Reverse token string e.g. "country" => "yrtnuoc".
+ *
+ * @version $Id$
+ */
+public final class ReverseStringFilter extends TokenFilter {
+
+  public ReverseStringFilter(TokenStream in) {
+    super(in);
+  }
+
+  public final Token next(Token in) throws IOException {
+    for (Token token=input.next(in); token!=null; token=input.next(in)) {
+      int len = token.termLength();
+      if( len <= 1 ) return token;
+      int num = len / 2;
+      char[] termBuffer = token.termBuffer();
+      char c;
+      for( int i = 0; i < num; i++ ){
+        c = termBuffer[i];
+        termBuffer[i] = termBuffer[len - i - 1];
+        termBuffer[len - i - 1] = c;
+      }
+      return token;
+    }
+    return null;
+  }
+}

Property changes on: src\java\org\apache\lucene\analysis\ReverseStringFilter.java
___________________________________________________________________
Added: svn:keywords
   + Author Date Id Revision
Added: svn:eol-style
   + native

Index: src/java/org/apache/lucene/analysis/ReverseStringAnalyzer.java
===================================================================
--- src/java/org/apache/lucene/analysis/ReverseStringAnalyzer.java	(revision 0)
+++ src/java/org/apache/lucene/analysis/ReverseStringAnalyzer.java	(revision 0)
@@ -0,0 +1,48 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.lucene.analysis;
+
+import java.io.IOException;
+import java.io.Reader;
+
+/**
+ * @version $Id$
+ */
+public class ReverseStringAnalyzer extends Analyzer {
+
+  public TokenStream tokenStream(String fieldName, Reader reader) {
+    return new ReverseStringFilter(new LowerCaseTokenizer(reader));
+  }
+
+  /** Filters LowerCaseTokenizer with ReverseStringFilter. */
+  private class SavedStreams {
+    Tokenizer source;
+    TokenStream result;
+  };
+  public TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException {
+    SavedStreams streams = (SavedStreams) getPreviousTokenStream();
+    if (streams == null) {
+      streams = new SavedStreams();
+      streams.source = new LowerCaseTokenizer(reader);
+      streams.result = new ReverseStringFilter(streams.source);
+      setPreviousTokenStream(streams);
+    } else
+      streams.source.reset(reader);
+    return streams.result;
+  }
+}

Property changes on: src\java\org\apache\lucene\analysis\ReverseStringAnalyzer.java
___________________________________________________________________
Added: svn:keywords
   + Author Date Id Revision
Added: svn:eol-style
   + native

Index: src/java/org/apache/lucene/search/PrefixQuery.java
===================================================================
--- src/java/org/apache/lucene/search/PrefixQuery.java	(revision 697643)
+++ src/java/org/apache/lucene/search/PrefixQuery.java	(working copy)
@@ -31,9 +31,27 @@
 
   /** Constructs a query for terms starting with <code>prefix</code>. */
   public PrefixQuery(Term prefix) {
-    this.prefix = prefix;
+    this(prefix,false);
   }
 
+  public PrefixQuery(Term prefix, boolean reverse) {
+    if(reverse){
+      String s = prefix.text();
+      int len = s.length();
+      if( len <= 1 ){
+        this.prefix = prefix;
+        return;
+      }
+      StringBuffer sb = new StringBuffer(len);
+      for( int i = 0; i < len; i++ ){
+        sb.append( s.charAt( len - i - 1 ) );
+      }
+      this.prefix = new Term(prefix.field(),sb.toString());
+    }
+    else
+      this.prefix = prefix;
+  }
+
   /** Returns the prefix of this query. */
   public Term getPrefix() { return prefix; }
 
@@ -47,7 +65,7 @@
         Term term = enumerator.term();
         if (term != null &&
             term.text().startsWith(prefixText) &&
-            term.field() == prefixField) // interned comparison 
+            term.field() == prefixField) // interned comparison
         {
           TermQuery tq = new TermQuery(term);	  // found a match
           tq.setBoost(getBoost());                // set the boost