/*
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.advanced;
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;
import org.geogebra.common.kernel.geos.GeoNumeric;
/**
* Selected 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.
*
*/
public class AlgoSelectedElement extends AlgoElement {
private GeoList geoList; // input
private GeoElement element; // output
/**
* Creates new selected element algo
*
* @param cons
* construction
* @param label
* output label
* @param geoList
* list
*/
public AlgoSelectedElement(Construction cons, String label,
GeoList geoList) {
super(cons);
this.geoList = geoList;
// init return element as copy of first list element
if (geoList.size() > 0) {
// create copy of first GeoElement in list
element = geoList.get(0).copyInternal(cons);
}
// desperate case: empty list
else {
element = new GeoNumeric(cons);
}
setInputOutput();
compute();
element.setLabel(label);
}
@Override
public Commands getClassName() {
return Commands.SelectedElement;
}
@Override
protected void setInputOutput() {
input = new GeoElement[1];
input[0] = geoList;
setOutputLength(1);
setOutput(0, element);
setDependencies(); // done by AlgoElement
}
/**
* Returns the selected element
*
* @return selected element
*/
public GeoElement getElement() {
return element;
}
@Override
public final void compute() {
if (!geoList.isDefined()) {
element.setUndefined();
return;
}
GeoElement geo = geoList.getSelectedElement();
// check type:
if (geo != null && geo.getGeoClassType() == element.getGeoClassType()) {
element.set(geo);
} else {
element.setUndefined();
}
}
}