1 files changed, 57 insertions, 10 deletions
diff --git a/src/de/lmu/ifi/dbs/elki/database/datastore/DataStoreUtil.java b/src/de/lmu/ifi/dbs/elki/database/datastore/DataStoreUtil.java
index 6d0c2d0f..5369dda9 100644
--- a/src/de/lmu/ifi/dbs/elki/database/datastore/DataStoreUtil.java
+++ b/src/de/lmu/ifi/dbs/elki/database/datastore/DataStoreUtil.java
@@ -4,7 +4,7 @@ package de.lmu.ifi.dbs.elki.database.datastore;
  This file is part of ELKI:
  Environment for Developing KDD-Applications Supported by Index-Structures
 
- Copyright (C) 2013
+ Copyright (C) 2014
  Ludwig-Maximilians-Universität München
  Lehr- und Forschungseinheit für Datenbanksysteme
  ELKI Development Team
@@ -23,8 +23,10 @@ package de.lmu.ifi.dbs.elki.database.datastore;
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+import java.util.Comparator;
+
+import de.lmu.ifi.dbs.elki.database.ids.DBIDRef;
 import de.lmu.ifi.dbs.elki.database.ids.DBIDs;
-import de.lmu.ifi.dbs.elki.distance.distancevalue.DoubleDistance;
 
 /**
  * Storage utility class. Mostly a shorthand for
@@ -126,15 +128,60 @@ public final class DataStoreUtil {
   }
 
   /**
-   * Make a new storage, to associate the given ids with an double valued
-   * distance.
+   * Sort objects by a double relation
    * 
-   * @param ids DBIDs to store data for
-   * @param hints Hints for the storage manager
-   * @return new data store
+   * @author Erich Schubert
+   * 
+   * @apiviz.exclude
    */
-  public static WritableDoubleDistanceDataStore makeDoubleDistanceStorage(DBIDs ids, int hints) {
-    // FIXME: this is an ugly work-around.
-    return (WritableDoubleDistanceDataStore) DataStoreFactory.FACTORY.makeStorage(ids, hints, DoubleDistance.class);
+  public static class AscendingByDoubleDataStore implements Comparator<DBIDRef> {
+    /**
+     * Scores to use for sorting.
+     */
+    private final DoubleDataStore scores;
+    
+    /**
+     * Constructor.
+     *
+     * @param scores Scores for sorting
+     */
+    public AscendingByDoubleDataStore(DoubleDataStore scores) {
+      super();
+      this.scores = scores;
+    }
+
+    @Override
+    public int compare(DBIDRef id1, DBIDRef id2) {
+      return Double.compare(scores.doubleValue(id1), scores.doubleValue(id2));
+    }
+  }
+
+  /**
+   * Sort objects by a double relation
+   * 
+   * @author Erich Schubert
+   * 
+   * @apiviz.exclude
+   */
+  public static class DescendingByDoubleDataStore implements Comparator<DBIDRef> {
+    /**
+     * Scores to use for sorting.
+     */
+    private final DoubleDataStore scores;
+    
+    /**
+     * Constructor.
+     *
+     * @param scores Scores for sorting
+     */
+    public DescendingByDoubleDataStore(DoubleDataStore scores) {
+      super();
+      this.scores = scores;
+    }
+
+    @Override
+    public int compare(DBIDRef id1, DBIDRef id2) {
+      return Double.compare(scores.doubleValue(id2), scores.doubleValue(id1));
+    }
   }
 }