1 files changed, 190 insertions, 0 deletions
diff --git a/src/de/lmu/ifi/dbs/elki/datasource/filter/typeconversions/ClassLabelFilter.java b/src/de/lmu/ifi/dbs/elki/datasource/filter/typeconversions/ClassLabelFilter.java
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@@ -0,0 +1,190 @@
+package de.lmu.ifi.dbs.elki.datasource.filter.typeconversions;
+
+/*
+ This file is part of ELKI:
+ Environment for Developing KDD-Applications Supported by Index-Structures
+
+ Copyright (C) 2014
+ Ludwig-Maximilians-Universität München
+ Lehr- und Forschungseinheit für Datenbanksysteme
+ ELKI Development Team
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import java.util.ArrayList;
+import java.util.List;
+
+import de.lmu.ifi.dbs.elki.data.ClassLabel;
+import de.lmu.ifi.dbs.elki.data.LabelList;
+import de.lmu.ifi.dbs.elki.data.SimpleClassLabel;
+import de.lmu.ifi.dbs.elki.data.type.SimpleTypeInformation;
+import de.lmu.ifi.dbs.elki.datasource.bundle.MultipleObjectsBundle;
+import de.lmu.ifi.dbs.elki.datasource.filter.ObjectFilter;
+import de.lmu.ifi.dbs.elki.utilities.Alias;
+import de.lmu.ifi.dbs.elki.utilities.exceptions.AbortException;
+import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
+import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
+import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameterization.Parameterization;
+import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.IntParameter;
+import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.ObjectParameter;
+
+/**
+ * Class that turns a label column into a class label column.
+ * 
+ * @author Erich Schubert
+ * 
+ * @apiviz.uses LabelList oneway - - «reads»
+ * @apiviz.has ClassLabel
+ */
+@Alias({ "de.lmu.ifi.dbs.elki.datasource.filter.normalization.ClassLabelFilter" })
+public class ClassLabelFilter implements ObjectFilter {
+  /**
+   * The index of the label to be used as class label, null if no class label is
+   * specified.
+   */
+  private final int classLabelIndex;
+
+  /**
+   * The class label class to use.
+   */
+  private final ClassLabel.Factory<?> classLabelFactory;
+
+  /**
+   * Constructor.
+   * 
+   * @param classLabelIndex The index to convert
+   * @param classLabelFactory The class label factory to use
+   */
+  public ClassLabelFilter(int classLabelIndex, ClassLabel.Factory<?> classLabelFactory) {
+    super();
+    this.classLabelIndex = classLabelIndex;
+    this.classLabelFactory = classLabelFactory;
+  }
+
+  @Override
+  public MultipleObjectsBundle filter(MultipleObjectsBundle objects) {
+    MultipleObjectsBundle bundle = new MultipleObjectsBundle();
+    // Find a labellist column
+    boolean done = false;
+    boolean keeplabelcol = false;
+    for(int i = 0; i < objects.metaLength(); i++) {
+      SimpleTypeInformation<?> meta = objects.meta(i);
+      // Skip non-labellist columns - or if we already had a labellist
+      if(done || !LabelList.class.equals(meta.getRestrictionClass())) {
+        bundle.appendColumn(meta, objects.getColumn(i));
+        continue;
+      }
+      done = true;
+
+      // We split the label column into two parts
+      List<ClassLabel> clscol = new ArrayList<>(objects.dataLength());
+      List<LabelList> lblcol = new ArrayList<>(objects.dataLength());
+
+      ArrayList<String> lbuf = new ArrayList<>();
+      // Split the column
+      for(Object obj : objects.getColumn(i)) {
+        if(obj != null) {
+          LabelList ll = (LabelList) obj;
+          int off = (classLabelIndex >= 0) ? classLabelIndex : (ll.size() - classLabelIndex);
+          try {
+            ClassLabel lbl = classLabelFactory.makeFromString(ll.get(off));
+            clscol.add(lbl);
+          }
+          catch(Exception e) {
+            throw new AbortException("Cannot initialize class labels: " + e.getMessage(), e);
+          }
+          lbuf.clear();
+          for(int j = 0; j < ll.size(); j++) {
+            if(j == off) {
+              continue;
+            }
+            lbuf.add(ll.get(j));
+          }
+          lblcol.add(LabelList.make(lbuf));
+          if(lbuf.size() > 0) {
+            keeplabelcol = true;
+          }
+        }
+        else {
+          clscol.add(null);
+          lblcol.add(null);
+        }
+      }
+      bundle.appendColumn(classLabelFactory.getTypeInformation(), clscol);
+      // Only add the label column when it's not empty.
+      if(keeplabelcol) {
+        bundle.appendColumn(meta, lblcol);
+      }
+    }
+    return bundle;
+  }
+
+  /**
+   * Parameterization class.
+   * 
+   * @author Erich Schubert
+   * 
+   * @apiviz.exclude
+   */
+  public static class Parameterizer extends AbstractParameterizer {
+    /**
+     * Optional parameter that specifies the index of the label to be used as
+     * class label, must be an integer equal to or greater than 0.
+     * <p>
+     * Key: {@code -dbc.classLabelIndex}
+     * </p>
+     */
+    public static final OptionID CLASS_LABEL_INDEX_ID = new OptionID("dbc.classLabelIndex", "The index of the label to be used as class label. The first label is 0, negative indexes are relative to the end.");
+
+    /**
+     * Parameter to specify the class of occurring class labels.
+     * <p>
+     * Key: {@code -dbc.classLabelClass}
+     * </p>
+     */
+    public static final OptionID CLASS_LABEL_CLASS_ID = new OptionID("dbc.classLabelClass", "Class label class to use.");
+
+    /**
+     * The index of the label to be used as class label, null if no class label
+     * is specified.
+     */
+    protected int classLabelIndex;
+
+    /**
+     * The class label factory to use.
+     */
+    private ClassLabel.Factory<?> classLabelFactory;
+
+    @Override
+    protected void makeOptions(Parameterization config) {
+      super.makeOptions(config);
+      // parameter class label index
+      final IntParameter classLabelIndexParam = new IntParameter(CLASS_LABEL_INDEX_ID);
+      final ObjectParameter<ClassLabel.Factory<?>> classlabelClassParam = new ObjectParameter<>(CLASS_LABEL_CLASS_ID, ClassLabel.Factory.class, SimpleClassLabel.Factory.class);
+
+      config.grab(classLabelIndexParam);
+      config.grab(classlabelClassParam);
+      if(classLabelIndexParam.isDefined() && classlabelClassParam.isDefined()) {
+        classLabelIndex = classLabelIndexParam.intValue();
+        classLabelFactory = classlabelClassParam.instantiateClass(config);
+      }
+    }
+
+    @Override
+    protected ClassLabelFilter makeInstance() {
+      return new ClassLabelFilter(classLabelIndex, classLabelFactory);
+    }
+  }
+}