NothingPicker.java

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/*
    Synthia, a data structure generator
    Copyright (C) 2019-2021 Laboratoire d'informatique formelle
    Université du Québec à Chicoutimi, Canada
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package ca.uqac.lif.synthia.util;
 
import ca.uqac.lif.petitpoucet.NodeFactory;
import ca.uqac.lif.petitpoucet.Part;
import ca.uqac.lif.petitpoucet.PartNode;
import ca.uqac.lif.petitpoucet.function.ExplanationQueryable;
import ca.uqac.lif.synthia.NoMoreElementException;
import ca.uqac.lif.synthia.Picker;
import ca.uqac.lif.synthia.Shrinkable;
 
/**
 * A {@link RelativePicker} that only throws a {@link NoMoreElementException}
 * when the {@link #pick()} method is called.
 *
 * @param <T> The type of the picker (but not really important here).
 * @ingroup API
 */
public class NothingPicker<T> implements Shrinkable<T>, ExplanationQueryable
{
    /**
     * Creates a new instance of the picker.
     */
    public NothingPicker()
    {
        super();
    }
    
    @Override
    public NothingPicker<T> shrink(T o, Picker<Float> decision, float m)
    {
        return new NothingPicker<T>();
    }
 
    @Override
    public void reset()
    {
        //Nothing to do here.
    }
 
    @Override
    public T pick()
    {
        throw  new NoMoreElementException();
    }
 
    @Override
    public Picker<T> duplicate(boolean with_state)
    {
        return new NothingPicker<T>();
    }
 
    @Override
    public PartNode getExplanation(Part p)
    {
        return getExplanation(p, NodeFactory.getFactory());
    }
 
    @Override
    public PartNode getExplanation(Part p, NodeFactory arg1)
    {
        // Nothing is the end of the chain
        return null;
    }
 
    @Override
    public Shrinkable<T> shrink(T o)
    {
        return shrink(o, null, 1);
    }
}