/*

 * Copyright (c) 2003, 2013, 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.security;

import java.io.*;

import java.security.cert.CertPath;

/**

 * This class encapsulates information about a code signer.

 * It is immutable.

 *

 * @since 1.5

 * @author Vincent Ryan

 */

public final class CodeSigner implements Serializable {

    private static final long serialVersionUID = 6819288105193937581L;

    /**

     * The signer's certificate path.

     *

     * @serial

     */

    private CertPath signerCertPath;

    /*

     * The signature timestamp.

     *

     * @serial

     */

    private Timestamp timestamp;

    /*

     * Hash code for this code signer.

     */

    private transient int myhash = -1;

    /**

     * Constructs a CodeSigner object.

     *

     * @param signerCertPath The signer's certificate path.

     *                       It must not be {@code null}.

     * @param timestamp A signature timestamp.

     *                  If {@code null} then no timestamp was generated

     *                  for the signature.

     * @throws NullPointerException if {@code signerCertPath} is

     *                              {@code null}.

     */

    public CodeSigner(CertPath signerCertPath, Timestamp timestamp) {

        if (signerCertPath == null) {

            throw new NullPointerException();

        }

        this.signerCertPath = signerCertPath;

        this.timestamp = timestamp;

    }

    /**

     * Returns the signer's certificate path.

     *

     * @return A certificate path.

     */

    public CertPath getSignerCertPath() {

        return signerCertPath;

    }

    /**

     * Returns the signature timestamp.

     *

     * @return The timestamp or {@code null} if none is present.

     */

    public Timestamp getTimestamp() {

        return timestamp;

    }

    /**

     * Returns the hash code value for this code signer.

     * The hash code is generated using the signer's certificate path and the

     * timestamp, if present.

     *

     * @return a hash code value for this code signer.

     */

    public int hashCode() {

        if (myhash == -1) {

            if (timestamp == null) {

                myhash = signerCertPath.hashCode();

            } else {

                myhash = signerCertPath.hashCode() + timestamp.hashCode();

            }

        }

        return myhash;

    }

    /**

     * Tests for equality between the specified object and this

     * code signer. Two code signers are considered equal if their

     * signer certificate paths are equal and if their timestamps are equal,

     * if present in both.

     *

     * @param obj the object to test for equality with this object.

     *

     * @return true if the objects are considered equal, false otherwise.

     */

    public boolean equals(Object obj) {

        if (obj == null || (!(obj instanceof CodeSigner))) {

            return false;

        }

        CodeSigner that = (CodeSigner)obj;

        if (this == that) {

            return true;

        }

        Timestamp thatTimestamp = that.getTimestamp();

        if (timestamp == null) {

            if (thatTimestamp != null) {

                return false;

            }

        } else {

            if (thatTimestamp == null ||

                (! timestamp.equals(thatTimestamp))) {

                return false;

            }

        }

        return signerCertPath.equals(that.getSignerCertPath());

    }

    /**

     * Returns a string describing this code signer.

     *

     * @return A string comprising the signer's certificate and a timestamp,

     *         if present.

     */

    public String toString() {

        StringBuffer sb = new StringBuffer();

        sb.append("(");

        sb.append("Signer: " + signerCertPath.getCertificates().get(0));

        if (timestamp != null) {

            sb.append("timestamp: " + timestamp);

        }

        sb.append(")");

        return sb.toString();

    }

    // Explicitly reset hash code value to -1

    private void readObject(ObjectInputStream ois)

        throws IOException, ClassNotFoundException {

     ois.defaultReadObject();

     myhash = -1;

    }

}