/*
 Copyright (C) 2007 Richard Gomes

 This source code is release under the BSD License.

 This file is part of JQuantLib, a free-software/open-source library
 for financial quantitative analysts and developers - http://jquantlib.org/

 JQuantLib is free software: you can redistribute it and/or modify it
 under the terms of the JQuantLib license.  You should have received a
 copy of the license along with this program; if not, please email
 . The license is also available online at
 .

 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 license for more details.

 JQuantLib is based on QuantLib. http://quantlib.org/
 When applicable, the original copyright notice follows this notice.
 */

/*
 Copyright (C) 2003, 2006 Ferdinando Ametrano
 Copyright (C) 2006 Warren Chou
 Copyright (C) 2006 StatPro Italia srl
 Copyright (C) 2006 Chiara Fornarola

 This file is part of QuantLib, a free-software/open-source library
 for financial quantitative analysts and developers - http://quantlib.org/

 QuantLib is free software: you can redistribute it and/or modify it
 under the terms of the QuantLib license.  You should have received a
 copy of the license along with this program; if not, please email
 . The license is also available online at
 .

 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 license for more details.
*/

package org.jquantlib.instruments;

import org.jquantlib.lang.exceptions.LibraryException;
import org.jquantlib.util.PolymorphicVisitor;
import org.jquantlib.util.Visitor;

/**
 * Binary asset-or-nothing payoff which pays off nothing if the underlying asset price {@latex$ S_{T}} finishes
 * below/above the strike price {@latex$ K}, or pays out the asset price {@latex$ S_{T}} itself if the underlying asset finishes
 * above/below the strike price.
 * 

 * Definitions of Binary path-independent payoffs can be found in
 * M. Rubinstein, E. Reiner:"Unscrambling The Binary Code", Risk, Vol.4 no.9,1991.
 *
 * @see Binary Options
 *
 * @author Richard Gomes
 */
public class AssetOrNothingPayoff extends StrikedTypePayoff {

	//
    // public constructors
    //

    /**
     * Constructs a typed {@link Payoff} with a fixed strike price and the policy of an asset-or-nothing payoff
     *
     * @param type is an {@link Option.Type}
     * @param strike is the strike price
     */
    public AssetOrNothingPayoff(final Option.Type type, final/* @Real */double strike) {
		super(type, strike);
	}


	//
    // Overrides Payoff
    //

    @Override
    public String name() /* @ReadOnly */ {
        return "AssetOrNothing";
    }

    /**
     * {@inheritDoc}
     * 

     * Pays off nothing if the underlying asset price {@latex$ S_{T}} finishes below/above the strike price {@latex$ K}, or pays
     * out the asset price {@latex$ S_{T}} itself if the underlying asset finishes above/below the strike price.
     * 
CALL Option: if {@latex$ S_{T}>K \rightarrow S_{T}}, otherwise zero
     * 
PUT Option: if {@latex$ K>S_{T} \rightarrow S_{T}}, otherwise zero
     * where {@latex$ S_{T}} is the asset price at maturity
     */
    @Override
    public final double get(final double price) /* @ReadOnly */ {
		if (type == Option.Type.Call)
            return (price - strike > 0.0) ? price : 0.0;
        else if (type == Option.Type.Put)
            return (strike - price > 0.0) ? price : 0.0;
        else
            throw new LibraryException("unknown/illegal option type"); // TODO: message
	}


	//
	// implements PolymorphicVisitable
	//

	@Override
	public void accept(final PolymorphicVisitor pv) {
		final Visitor v = (pv!=null) ? pv.visitor(this.getClass()) : null;
        if (v != null) {
            v.visit(this);
        } else {
            super.accept(pv);
        }
	}

}