/*

 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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package java.security.spec;

import java.math.BigInteger;

/**

 * This immutable class specifies the set of domain parameters

 * used with elliptic curve cryptography (ECC).

 *

 * @see AlgorithmParameterSpec

 *

 * @author Valerie Peng

 *

 * @since 1.5

 */

public class ECParameterSpec implements AlgorithmParameterSpec {

    private final EllipticCurve curve;

    private final ECPoint g;

    private final BigInteger n;

    private final int h;

    /**

     * Creates elliptic curve domain parameters based on the

     * specified values.

     * @param curve the elliptic curve which this parameter

     * defines.

     * @param g the generator which is also known as the base point.

     * @param n the order of the generator <code>g</code>.

     * @param h the cofactor.

     * @exception NullPointerException if <code>curve</code>,

     * <code>g</code>, or <code>n</code> is null.

     * @exception IllegalArgumentException if <code>n</code>

     * or <code>h</code> is not positive.

     */

    public ECParameterSpec(EllipticCurve curve, ECPoint g,

                           BigInteger n, int h) {

        if (curve == null) {

            throw new NullPointerException("curve is null");

        }

        if (g == null) {

            throw new NullPointerException("g is null");

        }

        if (n == null) {

            throw new NullPointerException("n is null");

        }

        if (n.signum() != 1) {

            throw new IllegalArgumentException("n is not positive");

        }

        if (h <= 0) {

            throw new IllegalArgumentException("h is not positive");

        }

        this.curve = curve;

        this.g = g;

        this.n = n;

        this.h = h;

    }

    /**

     * Returns the elliptic curve that this parameter defines.

     * @return the elliptic curve that this parameter defines.

     */

    public EllipticCurve getCurve() {

        return curve;

    }

    /**

     * Returns the generator which is also known as the base point.

     * @return the generator which is also known as the base point.

     */

    public ECPoint getGenerator() {

        return g;

    }

    /**

     * Returns the order of the generator.

     * @return the order of the generator.

     */

    public BigInteger getOrder() {

        return n;

    }

    /**

     * Returns the cofactor.

     * @return the cofactor.

     */

    public int getCofactor() {

        return h;

    }

}