Mahout's DataModel as DataModel for issue #83

rival-core/pom.xml

@@ -16,10 +16,17 @@
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
         </dependency>
+
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-csv</artifactId>
             <version>1.0</version>
         </dependency>
+
+        <dependency>
+            <groupId>org.apache.mahout</groupId>
+            <artifactId>mahout-core</artifactId>
+            <version>${mahout.version}</version>
+        </dependency>
     </dependencies>
 </project>

rival-core/src/main/java/net/recommenders/rival/core/DataModelFactory.java

@@ -15,6 +15,8 @@
  */
 package net.recommenders.rival.core;
 
+import net.recommenders.rival.core.ext.MahoutDataModel;
+
 /**
  *
  * @author <a href="http://github.com/abellogin">Alejandro</a>
@@ -33,4 +35,7 @@ public static <U, I> TemporalDataModelIF<U, I> getSimpleTemporalModel() {
         return new TemporalDataModel<>();
     }
 
+    public static TemporalDataModelIF<Long, Long> getMahoutTemporalModel() {
+        return new MahoutDataModel();
+    }
 }

rival-core/src/main/java/net/recommenders/rival/core/ext/MahoutDataModel.java

@@ -0,0 +1,171 @@
+/*
+ * Copyright 2016 recommenders.net.
+ *
+ * Licensed 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 net.recommenders.rival.core.ext;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import net.recommenders.rival.core.TemporalDataModelIF;
+import org.apache.mahout.cf.taste.common.TasteException;
+import org.apache.mahout.cf.taste.impl.common.FastByIDMap;
+import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
+import org.apache.mahout.cf.taste.impl.model.GenericDataModel;
+import org.apache.mahout.cf.taste.impl.model.GenericPreference;
+import org.apache.mahout.cf.taste.model.Preference;
+import org.apache.mahout.cf.taste.model.PreferenceArray;
+
+/**
+ *
+ * @author <a href="http://github.com/abellogin">Alejandro</a>
+ */
+public class MahoutDataModel implements TemporalDataModelIF<Long, Long> {
+
+    private GenericDataModel model;
+    private FastByIDMap<Collection<Preference>> data;
+    private FastByIDMap<FastByIDMap<Long>> timestampData;
+
+    public MahoutDataModel() {
+        model = null;
+        data = new FastByIDMap<Collection<Preference>>();
+        timestampData = new FastByIDMap<FastByIDMap<Long>>();
+    }
+
+    private void generateDatamodel() {
+        FastByIDMap<PreferenceArray> userData = GenericDataModel.toDataMap(data, true);
+        model = new GenericDataModel(userData, timestampData);
+        data = null;
+        timestampData = null;
+    }
+
+    @Override
+    public void addPreference(Long u, Long i, Double d) {
+        if (model != null) {
+            throw new IllegalArgumentException("DataModel already generated. It is not possible to add more information.");
+        }
+        Collection<Preference> prefs = null;
+        if (!data.containsKey(u)) {
+            prefs = new ArrayList<Preference>();
+            data.put(u, prefs);
+        } else {
+            prefs = data.get(u);
+        }
+        prefs.add(new GenericPreference(u, i, d.floatValue()));
+    }
+
+    @Override
+    public void addTimestamp(Long u, Long i, Long t) {
+        if (model != null) {
+            throw new IllegalArgumentException("DataModel already generated. It is not possible to add more information.");
+        }
+        FastByIDMap<Long> prefs = null;
+        if (!timestampData.containsKey(u)) {
+            prefs = new FastByIDMap<Long>();
+            timestampData.put(u, prefs);
+        } else {
+            prefs = timestampData.get(u);
+        }
+        prefs.put(i, t);
+    }
+
+    @Override
+    public Double getUserItemPreference(Long u, Long i) {
+        if (model == null) {
+            generateDatamodel();
+        }
+        try {
+            return model.getPreferenceValue(u, i) * 1.0;
+        } catch (TasteException e) {
+            e.printStackTrace();
+        }
+        return Double.NaN;
+    }
+
+    @Override
+    public Iterable<Long> getUserItemTimestamps(Long u, Long i) {
+        if (model == null) {
+            generateDatamodel();
+        }
+        List<Long> t = new ArrayList<>();
+        try {
+            t.add(model.getPreferenceTime(u, i));
+        } catch (TasteException e) {
+            e.printStackTrace();
+        }
+        return t;
+    }
+
+    @Override
+    public Iterable<Long> getUserItems(Long u) {
+        if (model == null) {
+            generateDatamodel();
+        }
+        try {
+            return model.getItemIDsFromUser(u);
+        } catch (TasteException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    @Override
+    public Iterable<Long> getItems() {
+        if (model == null) {
+            generateDatamodel();
+        }
+        List<Long> items = new ArrayList<>();
+        LongPrimitiveIterator lpi = model.getItemIDs();
+        while (lpi.hasNext()) {
+            items.add(lpi.nextLong());
+        }
+        return items;
+    }
+
+    @Override
+    public Iterable<Long> getUsers() {
+        if (model == null) {
+            generateDatamodel();
+        }
+        List<Long> users = new ArrayList<>();
+        LongPrimitiveIterator lpi = model.getUserIDs();
+        while (lpi.hasNext()) {
+            users.add(lpi.nextLong());
+        }
+        return users;
+    }
+
+    @Override
+    public int getNumItems() {
+        if (model == null) {
+            generateDatamodel();
+        }
+        return model.getNumItems();
+    }
+
+    @Override
+    public int getNumUsers() {
+        if (model == null) {
+            generateDatamodel();
+        }
+        return model.getNumUsers();
+    }
+
+    @Override
+    public void clear() {
+        model = null;
+        data = new FastByIDMap<Collection<Preference>>();
+        timestampData = new FastByIDMap<FastByIDMap<Long>>();
+    }
+}