/*

 * Copyright 1997-2006 Sun Microsystems, Inc.  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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.x509;

import java.io.IOException;

import java.io.OutputStream;

import java.math.BigInteger;

import java.util.Enumeration;

import sun.security.util.*;

/**

 * Represent the CRL Number Extension.

 *

 * <p>This extension, if present, conveys a monotonically increasing

 * sequence number for each CRL issued by a given CA through a specific

 * CA X.500 Directory entry or CRL distribution point. This extension

 * allows users to easily determine when a particular CRL supersedes

 * another CRL.

 *

 * @author Hemma Prafullchandra

 * @see Extension

 * @see CertAttrSet

 */

public class CRLNumberExtension extends Extension

implements CertAttrSet<String> {

    /**

     * Attribute name.

     */

    public static final String NAME = "CRLNumber";

    public static final String NUMBER = "value";

    private static final String LABEL = "CRL Number";

    private BigInteger crlNumber = null;

    private String extensionName;

    private String extensionLabel;

    // Encode this extension value

    private void encodeThis() throws IOException {

        if (crlNumber == null) {

            this.extensionValue = null;

            return;

        }

        DerOutputStream os = new DerOutputStream();

        os.putInteger(this.crlNumber);

        this.extensionValue = os.toByteArray();

    }

    /**

     * Create a CRLNumberExtension with the integer value .

     * The criticality is set to false.

     *

     * @param crlNum the value to be set for the extension.

     */

    public CRLNumberExtension(int crlNum) throws IOException {

        this(PKIXExtensions.CRLNumber_Id, false, BigInteger.valueOf(crlNum),

        NAME, LABEL);

    }

    /**

     * Create a CRLNumberExtension with the BigInteger value .

     * The criticality is set to false.

     *

     * @param crlNum the value to be set for the extension.

     */

    public CRLNumberExtension(BigInteger crlNum) throws IOException {

        this(PKIXExtensions.CRLNumber_Id, false, crlNum, NAME, LABEL);

    }

    /**

     * Creates the extension (also called by the subclass).

     */

    protected CRLNumberExtension(ObjectIdentifier extensionId,

        boolean isCritical, BigInteger crlNum, String extensionName,

        String extensionLabel) throws IOException {

        this.extensionId = extensionId;

        this.critical = isCritical;

        this.crlNumber = crlNum;

        this.extensionName = extensionName;

        this.extensionLabel = extensionLabel;

        encodeThis();

    }

    /**

     * Create the extension from the passed DER encoded value of the same.

     *

     * @param critical true if the extension is to be treated as critical.

     * @param value an array of DER encoded bytes of the actual value.

     * @exception ClassCastException if value is not an array of bytes

     * @exception IOException on error.

     */

    public CRLNumberExtension(Boolean critical, Object value)

    throws IOException {

        this(PKIXExtensions.CRLNumber_Id, critical, value, NAME, LABEL);

    }

    /**

     * Creates the extension (also called by the subclass).

     */

    protected CRLNumberExtension(ObjectIdentifier extensionId,

        Boolean critical, Object value, String extensionName,

        String extensionLabel) throws IOException {

        this.extensionId = extensionId;

        this.critical = critical.booleanValue();

        this.extensionValue = (byte[]) value;

        DerValue val = new DerValue(this.extensionValue);

        this.crlNumber = val.getBigInteger();

        this.extensionName = extensionName;

        this.extensionLabel = extensionLabel;

    }

    /**

     * Set the attribute value.

     */

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

        if (name.equalsIgnoreCase(NUMBER)) {

            if (!(obj instanceof BigInteger)) {

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

            }

            crlNumber = (BigInteger)obj;

        } else {

          throw new IOException("Attribute name not recognized by"

                                + " CertAttrSet:" + extensionName + ".");

        }

        encodeThis();

    }

    /**

     * Get the attribute value.

     */

    public Object get(String name) throws IOException {

        if (name.equalsIgnoreCase(NUMBER)) {

            if (crlNumber == null) return null;

            else return crlNumber;

        } else {

          throw new IOException("Attribute name not recognized by"

                                + " CertAttrSet:" + extensionName + ".");

        }

    }

    /**

     * Delete the attribute value.

     */

    public void delete(String name) throws IOException {

        if (name.equalsIgnoreCase(NUMBER)) {

            crlNumber = null;

        } else {

          throw new IOException("Attribute name not recognized by"

                                + " CertAttrSet:" + extensionName + ".");

        }

        encodeThis();

    }

    /**

     * Returns a printable representation of the CRLNumberExtension.

     */

    public String toString() {

        String s = super.toString() + extensionLabel + ": " +

                   ((crlNumber == null) ? "" : Debug.toHexString(crlNumber))

                   + "\n";

        return (s);

    }

    /**

     * Write the extension to the DerOutputStream.

     *

     * @param out the DerOutputStream to write the extension to.

     * @exception IOException on encoding errors.

     */

    public void encode(OutputStream out) throws IOException {

       DerOutputStream  tmp = new DerOutputStream();

        encode(out, PKIXExtensions.CRLNumber_Id, true);

    }

    /**

     * Write the extension to the DerOutputStream.

     * (Also called by the subclass)

     */

    protected void encode(OutputStream out, ObjectIdentifier extensionId,

        boolean isCritical) throws IOException {

       DerOutputStream  tmp = new DerOutputStream();

       if (this.extensionValue == null) {

           this.extensionId = extensionId;

           this.critical = isCritical;

           encodeThis();

       }

       super.encode(tmp);

       out.write(tmp.toByteArray());

    }

    /**

     * Return an enumeration of names of attributes existing within this

     * attribute.

     */

    public Enumeration<String> getElements() {

        AttributeNameEnumeration elements = new AttributeNameEnumeration();

        elements.addElement(NUMBER);

        return (elements.elements());

    }

    /**

     * Return the name of this attribute.

     */

    public String getName() {

        return (extensionName);

    }

}