/*
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org
This file is part of GeoGebra.
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation.
*/
package org.geogebra.common.kernel.statistics;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.algos.AlgoElement;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoList;
/**
* random element of a GeoList object.
*
* Note: the type of the returned GeoElement object is determined by the type of
* the first list element. If the list is initially empty, a GeoNumeric object
* is created for element.
*
* @author Michael
* @version 2010-06-01
*/
public class AlgoRandomElement extends AlgoElement {
private GeoList geoList; // input
private GeoElement element; // output
/**
* Creates new random element algo
*
* @param cons
* @param label
* @param geoList
*/
public AlgoRandomElement(Construction cons, String label, GeoList geoList) {
super(cons);
this.geoList = geoList;
// init return element as copy of first list element
if (geoList.size() > 0) {
element = geoList.get(0).copyInternal(cons);
} else if (geoList.getTypeStringForXML() != null) {
// if the list was non-empty at some point before saving, get the
// same type of geo
// saved in XML from 4.1.131.0
element = kernel.createGeoElement(cons,
geoList.getTypeStringForXML());
}
// desperate case: empty list
else {
// saved in XML from 4.0.18.0
element = cons.getOutputGeo();
}
setInputOutput();
compute();
element.setLabel(label);
cons.addRandomGeo(element);
}
@Override
public Commands getClassName() {
return Commands.RandomElement;
}
@Override
protected void setInputOutput() {
input = new GeoElement[1];
input[0] = geoList;
setOutputLength(1);
setOutput(0, element);
setDependencies(); // done by AlgoElement
}
/**
* Returns chosen element
*
* @return chosen element
*/
public GeoElement getElement() {
return element;
}
@Override
public final void compute() {
if (!geoList.isDefined() || geoList.size() == 0) {
element.setUndefined();
return;
}
GeoElement randElement = geoList.get((int) Math.floor(
(cons.getApplication().getRandomNumber() * geoList.size())));
// check type:
if (randElement.getGeoClassType() == element.getGeoClassType()) {
element.set(randElement);
} else {
element.setUndefined();
}
}
}