/*
 * Copyright (c) 2005, 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
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 */
/*
 * $Id: PGPData.java,v 1.4 2005/05/10 16:35:35 mullan Exp $
 */
package javax.xml.crypto.dsig.keyinfo;

import java.util.Collections;
import java.util.List;
import javax.xml.crypto.XMLStructure;

/**
 * A representation of the XML <code>PGPData</code> element as defined in
 * the <a href="http://www.w3.org/TR/xmldsig-core/">
 * W3C Recommendation for XML-Signature Syntax and Processing</a>. A
 * <code>PGPData</code> object is used to convey information related to
 * PGP public key pairs and signatures on such keys. The XML Schema Definition
 * is defined as:
 *
 * <pre>
 *    <element name="PGPData" type="ds:PGPDataType"/>
 *    <complexType name="PGPDataType">
 *      <choice>
 *        <sequence>
 *          <element name="PGPKeyID" type="base64Binary"/>
 *          <element name="PGPKeyPacket" type="base64Binary" minOccurs="0"/>
 *          <any namespace="##other" processContents="lax" minOccurs="0"
 *           maxOccurs="unbounded"/>
 *        </sequence>
 *        <sequence>
 *          <element name="PGPKeyPacket" type="base64Binary"/>
 *          <any namespace="##other" processContents="lax" minOccurs="0"
 *           maxOccurs="unbounded"/>
 *        </sequence>
 *      </choice>
 *    </complexType>
 * </pre>
 *
 * A <code>PGPData</code> instance may be created by invoking one of the
 * {@link KeyInfoFactory#newPGPData newPGPData} methods of the {@link
 * KeyInfoFactory} class, and passing it
 * <code>byte</code> arrays representing the contents of the PGP public key
 * identifier and/or PGP key material packet, and an optional list of
 * elements from an external namespace.
 *
 * @author Sean Mullan
 * @author JSR 105 Expert Group
 * @since 1.6
 * @see KeyInfoFactory#newPGPData(byte[])
 * @see KeyInfoFactory#newPGPData(byte[], byte[], List)
 * @see KeyInfoFactory#newPGPData(byte[], List)
 */
public interface PGPData extends XMLStructure {

    /**
     * URI identifying the PGPData KeyInfo type:
     * http://www.w3.org/2000/09/xmldsig#PGPData. This can be specified as the
     * value of the <code>type</code> parameter of the {@link RetrievalMethod}
     * class to describe a remote <code>PGPData</code> structure.
     */
    final static String TYPE = "http://www.w3.org/2000/09/xmldsig#PGPData";

    /**
     * Returns the PGP public key identifier of this <code>PGPData</code> as
     * defined in <a href="http://www.ietf.org/rfc/rfc2440.txt">RFC 2440</a>,
     * section 11.2.
     *
     * @return the PGP public key identifier (may be <code>null</code> if
     *    not specified). Each invocation of this method returns a new clone
     *    to protect against subsequent modification.
     */
    byte[] getKeyId();

    /**
     * Returns the PGP key material packet of this <code>PGPData</code> as
     * defined in <a href="http://www.ietf.org/rfc/rfc2440.txt">RFC 2440</a>,
     * section 5.5.
     *
     * @return the PGP key material packet (may be <code>null</code> if not
     *    specified). Each invocation of this method returns a new clone to
     *    protect against subsequent modification.
     */
    byte[] getKeyPacket();

    /**
     * Returns an {@link Collections#unmodifiableList unmodifiable list}
     * of {@link XMLStructure}s representing elements from an external
     * namespace.
     *
     * @return an unmodifiable list of <code>XMLStructure</code>s (may be
     *    empty, but never <code>null</code>)
     */
    List getExternalElements();
}