add search method that allows Sort, but doesn't require a Filter

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1021360 13f79535-47bb-0310-9956-ffa450edef68

lucene/src/java/org/apache/lucene/search/Searcher.java

@@ -49,6 +49,19 @@ public abstract class Searcher implements Searchable {
     return search(createWeight(query), filter, n, sort);
   }
 
+  /**
+   * Search implementation with arbitrary sorting and no filter.
+   * @param query The query to search for
+   * @param n Return only the top n results
+   * @param sort The {@link org.apache.lucene.search.Sort} object
+   * @return The top docs, sorted according to the supplied {@link org.apache.lucene.search.Sort} instance
+   * @throws IOException
+   */
+  public TopFieldDocs search(Query query, int n,
+                             Sort sort) throws IOException {
+    return search(createWeight(query), null, n, sort);
+  }
+
   /** Lower-level search API.
   *
   * <p>{@link Collector#collect(int)} is called for every matching document.