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

package org.apache.samoa.moa.classifiers.core.conditionaltests;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * 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.
 * #L%
 */

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

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

  /**
   * Returns the number of the branch for an instance, -1 if unknown.
   * 
   * @param inst
   *          the instance to be used
   * @return the number of the branch for an instance, -1 if unknown.
   */
  public abstract int branchForInstance(Instance inst);

  /**
   * Gets whether the number of the branch for an instance is known.
   * 
   * @param inst
   * @return true if the number of the branch for an instance is known
   */
  public boolean resultKnownForInstance(Instance inst) {
    return branchForInstance(inst) >= 0;
  }

  /**
   * Gets the number of maximum branches, -1 if unknown.
   * 
   * @return the number of maximum branches, -1 if unknown..
   */
  public abstract int maxBranches();

  /**
   * Gets the text that describes the condition of a branch. It is used to describe the branch.
   * 
   * @param branch
   *          the number of the branch to describe
   * @param context
   *          the context or header of the data stream
   * @return the text that describes the condition of the branch
   */
  public abstract String describeConditionForBranch(int branch,
      InstancesHeader context);

  /**
   * Returns an array with the attributes that the test depends on.
   * 
   * @return an array with the attributes that the test depends on
   */
  public abstract int[] getAttsTestDependsOn();
}