/*

 * Copyright 2004-2006 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.util.*;

import sun.security.util.DerOutputStream;

import sun.security.util.DerValue;

/**

 * The Authority Information Access Extension (OID = 1.3.6.1.5.5.7.1.1).

 * <p>

 * The AIA extension identifies how to access CA information and services

 * for the certificate in which it appears. It enables CAs to issue their

 * certificates pre-configured with the URLs appropriate for contacting

 * services relevant to those certificates. For example, a CA may issue a

 * certificate that identifies the specific OCSP Responder to use when

 * performing on-line validation of that certificate.

 * <p>

 * This extension is defined in

 * <a href="http://www.ietf.org/rfc/rfc3280.txt">Internet X.509 PKI Certificate and Certificate Revocation List (CRL) Profile</a>. The profile permits

 * the extension to be included in end-entity or CA certificates,

 * and it must be marked as non-critical. Its ASN.1 definition is as follows:

 * <pre>

 *   id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 }

 *

 *   AuthorityInfoAccessSyntax  ::=

 *         SEQUENCE SIZE (1..MAX) OF AccessDescription

 *

 *   AccessDescription  ::=  SEQUENCE {

 *         accessMethod          OBJECT IDENTIFIER,

 *         accessLocation        GeneralName  }

 * </pre>

 * <p>

 * @see Extension

 * @see CertAttrSet

 */

public class AuthorityInfoAccessExtension extends Extension

        implements CertAttrSet<String> {

    /**

     * Identifier for this attribute, to be used with the

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

     */

    public static final String IDENT =

                                "x509.info.extensions.AuthorityInfoAccess";

    /**

     * Attribute name.

     */

    public static final String NAME = "AuthorityInfoAccess";

    public static final String DESCRIPTIONS = "descriptions";

    /**

     * The List of AccessDescription objects.

     */

    private List<AccessDescription> accessDescriptions;

    /**

     * Create an AuthorityInfoAccessExtension from a List of

     * AccessDescription; the criticality is set to false.

     *

     * @param accessDescriptions the List of AccessDescription

     * @throws IOException on error

     */

    public AuthorityInfoAccessExtension(

            List<AccessDescription> accessDescriptions) throws IOException {

        this.extensionId = PKIXExtensions.AuthInfoAccess_Id;

        this.critical = false;

        this.accessDescriptions = accessDescriptions;

        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 Array of DER encoded bytes of the actual value.

     * @exception IOException on error.

     */

    public AuthorityInfoAccessExtension(Boolean critical, Object value)

            throws IOException {

        this.extensionId = PKIXExtensions.AuthInfoAccess_Id;

        this.critical = critical.booleanValue();

        if (!(value instanceof byte[])) {

            throw new IOException("Illegal argument type");

        }

        extensionValue = (byte[])value;

        DerValue val = new DerValue(extensionValue);

        if (val.tag != DerValue.tag_Sequence) {

            throw new IOException("Invalid encoding for " +

                                  "AuthorityInfoAccessExtension.");

        }

        accessDescriptions = new ArrayList<AccessDescription>();

        while (val.data.available() != 0) {

            DerValue seq = val.data.getDerValue();

            AccessDescription accessDescription = new AccessDescription(seq);

            accessDescriptions.add(accessDescription);

        }

    }

    /**

     * Return the list of AccessDescription objects.

     */

    public List<AccessDescription> getAccessDescriptions() {

        return accessDescriptions;

    }

    /**

     * Return the name of this attribute.

     */

    public String getName() {

        return NAME;

    }

    /**

     * 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();

        if (this.extensionValue == null) {

            this.extensionId = PKIXExtensions.AuthInfoAccess_Id;

            this.critical = false;

            encodeThis();

        }

        super.encode(tmp);

        out.write(tmp.toByteArray());

    }

    /**

     * Set the attribute value.

     */

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

        if (name.equalsIgnoreCase(DESCRIPTIONS)) {

            if (!(obj instanceof List)) {

                throw new IOException("Attribute value should be of type List.");

            }

            accessDescriptions = (List<AccessDescription>)obj;

        } else {

            throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:AuthorityInfoAccessExtension.");

        }

        encodeThis();

    }

    /**

     * Get the attribute value.

     */

    public Object get(String name) throws IOException {

        if (name.equalsIgnoreCase(DESCRIPTIONS)) {

            return accessDescriptions;

        } else {

            throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:AuthorityInfoAccessExtension.");

        }

    }

    /**

     * Delete the attribute value.

     */

    public void delete(String name) throws IOException {

        if (name.equalsIgnoreCase(DESCRIPTIONS)) {

            accessDescriptions = new ArrayList<AccessDescription>();

        } else {

            throw new IOException("Attribute name [" + name +

                                "] not recognized by " +

                                "CertAttrSet:AuthorityInfoAccessExtension.");

        }

        encodeThis();

    }

    /**

     * Return an enumeration of names of attributes existing within this

     * attribute.

     */

    public Enumeration<String> getElements() {

        AttributeNameEnumeration elements = new AttributeNameEnumeration();

        elements.addElement(DESCRIPTIONS);

        return elements.elements();

    }

     // Encode this extension value

    private void encodeThis() throws IOException {

        if (accessDescriptions.isEmpty()) {

            this.extensionValue = null;

        } else {

            DerOutputStream ads = new DerOutputStream();

            for (AccessDescription accessDescription : accessDescriptions) {

                accessDescription.encode(ads);

            }

            DerOutputStream seq = new DerOutputStream();

            seq.write(DerValue.tag_Sequence, ads);

            this.extensionValue = seq.toByteArray();

        }

    }

    /**

     * Return the extension as user readable string.

     */

    public String toString() {

        return super.toString() + "AuthorityInfoAccess [\n  "

               + accessDescriptions + "\n]\n";

    }

}