samoa-api/src/main/java/org/apache/samoa/moa/classifiers/core/conditionaltests/NominalAttributeBinaryTest.java

/*
 * 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.samoa.moa.classifiers.core.conditionaltests;

import org.apache.samoa.instances.Instance;
import org.apache.samoa.instances.InstancesHeader;

/**
 * Nominal binary conditional test for instances to use to split nodes in Hoeffding trees.
 * 
 * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz)
 * @version $Revision: 7 $
 */
public class NominalAttributeBinaryTest extends InstanceConditionalBinaryTest {

  private static final long serialVersionUID = 1L;

  protected int attIndex;

  protected int attValue;

  public NominalAttributeBinaryTest(int attIndex, int attValue) {
    this.attIndex = attIndex;
    this.attValue = attValue;
  }

  @Override
  public int branchForInstance(Instance inst) {
    int instAttIndex = this.attIndex < inst.classIndex() ? this.attIndex
        : this.attIndex + 1;
    return inst.isMissing(instAttIndex) ? -1 : ((int) inst.value(instAttIndex) == this.attValue ? 0 : 1);
  }

  @Override
  public String describeConditionForBranch(int branch, InstancesHeader context) {
    if ((branch == 0) || (branch == 1)) {
      return InstancesHeader.getAttributeNameString(context,
          this.attIndex)
          + (branch == 0 ? " = " : " != ")
          + InstancesHeader.getNominalValueString(context,
              this.attIndex, this.attValue);
    }
    throw new IndexOutOfBoundsException();
  }

  @Override
  public void getDescription(StringBuilder sb, int indent) {
    // TODO Auto-generated method stub
  }

  @Override
  public int[] getAttsTestDependsOn() {
    return new int[] { this.attIndex };
  }
}