/*
 Copyright (C) 2007 John Martin

 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) 2006 Allen Kuo

 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.QL;
import org.jquantlib.lang.exceptions.LibraryException;


/**
 * Class for forward type payoffs
 *
 * @author John Martin
 */
public class ForwardTypePayoff extends Payoff {

    //
    // protected fields
    //

    /**
     * This field represents the {@link Forward}'s strike price
     */
    protected /* @Price */ double strike;

    protected Position type;

    //
    // public constructors
    //

    /**
     * Constructs a typed {@link Payoff} with a fixed strike price
     *
     * @param type is an {@link ForwardType}
     * @param strike is the strike price
     */
    public ForwardTypePayoff (final Position positionType, final/* @Price */double strike) {
        super ();
        QL.require (strike >= 0.0, "negative strike given"); // TODO: message
        this.strike = strike;
        this.type = positionType;
    }

    //
    // public final methods
    //

    /**
     * @return the strike value
     */
    public final/* @Strike */double strike () {
        return strike;
    }

    //
    // overrides Payoff
    //

    @Override
    public String description () /* @ReadOnly */ {
        final StringBuilder sb = new StringBuilder();
        sb.append (name());
        // Review, added this because it will be more helpful for debugging purposes.
        sb.append (this.type.toString());
        sb.append (" ");
        sb.append (this.strike);
        return sb.toString();
    }

    @Override
    public final double get (final double price) {
        if (type == Position.Long)
            return price - strike;
        else if (type == Position.Short)
            return strike - price;
        else
            throw new LibraryException (" Unknown Forward Type ");
    }

    @Override
    public String name () {
        return "Forward";
    }
    
}