/*

 * Copyright (c) 1997, 2011, 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

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 */

package sun.security.x509;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.Enumeration;

import sun.security.util.*;

/**

 * This class defines the AlgorithmId for the Certificate.

 *

 * @author Amit Kapoor

 * @author Hemma Prafullchandra

 */

public class CertificateAlgorithmId implements CertAttrSet<String> {

    private AlgorithmId algId;

    /**

     * Identifier for this attribute, to be used with the

     * get, set, delete methods of Certificate, x509 type.

     */

    public static final String IDENT = "x509.info.algorithmID";

    /**

     * Sub attributes name for this CertAttrSet.

     */

    public static final String NAME = "algorithmID";

    /**

     * Identifier to be used with get, set, and delete methods. When

     * using this identifier the associated object being passed in or

     * returned is an instance of AlgorithmId.

     * @see sun.security.x509.AlgorithmId

     */

    public static final String ALGORITHM = "algorithm";

    /**

     * Default constructor for the certificate attribute.

     *

     * @param algId the Algorithm identifier

     */

    public CertificateAlgorithmId(AlgorithmId algId) {

        this.algId = algId;

    }

    /**

     * Create the object, decoding the values from the passed DER stream.

     *

     * @param in the DerInputStream to read the serial number from.

     * @exception IOException on decoding errors.

     */

    public CertificateAlgorithmId(DerInputStream in) throws IOException {

        DerValue val = in.getDerValue();

        algId = AlgorithmId.parse(val);

    }

    /**

     * Create the object, decoding the values from the passed stream.

     *

     * @param in the InputStream to read the serial number from.

     * @exception IOException on decoding errors.

     */

    public CertificateAlgorithmId(InputStream in) throws IOException {

        DerValue val = new DerValue(in);

        algId = AlgorithmId.parse(val);

    }

    /**

     * Return the algorithm identifier as user readable string.

     */

    public String toString() {

        if (algId == null) return "";

        return (algId.toString() +

                ", OID = " + (algId.getOID()).toString() + "\n");

    }

    /**

     * Encode the algorithm identifier in DER form to the stream.

     *

     * @param out the DerOutputStream to marshal the contents to.

     * @exception IOException on errors.

     */

    public void encode(OutputStream out) throws IOException {

        DerOutputStream tmp = new DerOutputStream();

        algId.encode(tmp);

        out.write(tmp.toByteArray());

    }

    /**

     * Set the attribute value.

     */

    public void set(String name, Object obj) throws IOException {

        if (!(obj instanceof AlgorithmId)) {

            throw new IOException("Attribute must be of type AlgorithmId.");

        }

        if (name.equalsIgnoreCase(ALGORITHM)) {

            algId = (AlgorithmId)obj;

        } else {

            throw new IOException("Attribute name not recognized by " +

                              "CertAttrSet:CertificateAlgorithmId.");

        }

    }

    /**

     * Get the attribute value.

     */

    public AlgorithmId get(String name) throws IOException {

        if (name.equalsIgnoreCase(ALGORITHM)) {

            return (algId);

        } else {

            throw new IOException("Attribute name not recognized by " +

                               "CertAttrSet:CertificateAlgorithmId.");

        }

    }

    /**

     * Delete the attribute value.

     */

    public void delete(String name) throws IOException {

        if (name.equalsIgnoreCase(ALGORITHM)) {

            algId = null;

        } else {

            throw new IOException("Attribute name not recognized by " +

                               "CertAttrSet:CertificateAlgorithmId.");

        }

    }

    /**

     * Return an enumeration of names of attributes existing within this

     * attribute.

     */

    public Enumeration<String> getElements() {

        AttributeNameEnumeration elements = new AttributeNameEnumeration();

        elements.addElement(ALGORITHM);

        return (elements.elements());

    }

   /**

    * Return the name of this attribute.

    */

   public String getName() {

      return (NAME);

   }

}