source: trunk/CrossPare/src/de/ugoe/cs/cpdp/training/FixClass.java

// Copyright 2015 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.cpdp.training;

import weka.classifiers.AbstractClassifier;
import weka.core.Capabilities;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Utils;
import weka.core.Capabilities.Capability;

/**
 * Simple classifier that always predicts the same class
 * 
 * @author Steffen Herbold
 */
public class FixClass extends AbstractClassifier {

    /**
     * default serial ID
     */
    private static final long serialVersionUID = 1L;

    /**
     * default prediction: non-defective
     */
    private double fixedClassValue = 0.0d;

    /**
     * Returns default capabilities of the classifier.
     * 
     * @return the capabilities of this classifier
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enable(Capability.NOMINAL_ATTRIBUTES);
        result.enable(Capability.NUMERIC_ATTRIBUTES);
        result.enable(Capability.DATE_ATTRIBUTES);
        result.enable(Capability.STRING_ATTRIBUTES);
        result.enable(Capability.RELATIONAL_ATTRIBUTES);
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enable(Capability.NOMINAL_CLASS);
        result.enable(Capability.NUMERIC_CLASS);
        result.enable(Capability.MISSING_CLASS_VALUES);

        // instances
        result.setMinimumNumberInstances(0);

        return result;
    }

    /*
     * (non-Javadoc)
     * 
     * @see weka.classifiers.AbstractClassifier#setOptions(java.lang.String[])
     */
    @Override
    public void setOptions(String[] options) throws Exception {
        fixedClassValue = Double.parseDouble(Utils.getOption('C', options));
    }

    /*
     * (non-Javadoc)
     * 
     * @see weka.classifiers.AbstractClassifier#classifyInstance(weka.core.Instance)
     */
    @Override
    public double classifyInstance(Instance instance) {
        return fixedClassValue;
    }

    /*
     * (non-Javadoc)
     * 
     * @see weka.classifiers.Classifier#buildClassifier(weka.core.Instances)
     */
    @Override
    public void buildClassifier(Instances traindata) throws Exception {
        // do nothing
    }
}