/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.com
*
* 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/.
*/
package com.rapidminer.tools.math.similarity;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.Observable;
import com.rapidminer.tools.Observer;
/**
* This helper class installs and uninstalls additional ports at operators that operate on distance
* measures. It registers itself as an observer of the operator's parameters and instantiates a new
* {@link DistanceMeasure} whenever one of the parameters
* {@link DistanceMeasures#PARAMETER_MEASURE_TYPES},
* {@link DistanceMeasures#PARAMETER_MIXED_MEASURE},
* {@link DistanceMeasures#PARAMETER_NUMERICAL_MEASURE},
* {@link DistanceMeasures#PARAMETER_NOMINAL_MEASURE}, or
* {@link DistanceMeasures#PARAMETER_DIVERGENCE} changes. If the chosen {@link DistanceMeasure}
* overrides
* {@link DistanceMeasure#installAdditionalPorts(com.rapidminer.operator.ports.InputPorts, com.rapidminer.parameter.ParameterHandler)}
* this may install new ports at the operator.
*
* In its {@link Operator#doWork()} method, the operator may call
* {@link #getInitializedMeasure(ExampleSet)} in order to initialize the distance measure and obtain
* it. Call this method only once.
*
* @author Simon Fischer
*
*/
public class DistanceMeasureHelper {
private Operator operator;
private DistanceMeasure measure;
public DistanceMeasureHelper(Operator operator) {
this.operator = operator;
operator.getParameters().addObserver(new Observer<String>() {
@Override
public void update(Observable<String> observable, String arg) {
if (DistanceMeasures.PARAMETER_MEASURE_TYPES.equals(arg)
|| DistanceMeasures.PARAMETER_MIXED_MEASURE.equals(arg)
|| DistanceMeasures.PARAMETER_NUMERICAL_MEASURE.equals(arg)
|| DistanceMeasures.PARAMETER_NOMINAL_MEASURE.equals(arg)
|| DistanceMeasures.PARAMETER_DIVERGENCE.equals(arg)) {
updateMeasure();
}
}
}, false);
updateMeasure();
}
private void updateMeasure() {
if (measure != null) {
measure.uninstallAdditionalPorts(operator.getInputPorts());
}
try {
measure = DistanceMeasures.createMeasure(operator);
} catch (UndefinedParameterError e) {
operator.getLogger().warning("While updating distance measure: " + e.toString());
} catch (OperatorException e) {
operator.getLogger().warning("While updating distance measure: " + e.toString());
}
if (measure != null) {
measure.installAdditionalPorts(operator.getInputPorts(), operator);
}
}
public DistanceMeasure getInitializedMeasure(ExampleSet exampleSet) throws OperatorException {
updateMeasure();
measure.init(exampleSet, operator);
return measure;
}
public int getSelectedMeasureType() throws UndefinedParameterError {
return DistanceMeasures.getSelectedMeasureType(operator);
}
}