1/*
2 * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25/*
26 * $Id: RetrievalMethod.java,v 1.8 2005/05/10 16:35:35 mullan Exp $
27 */
28package javax.xml.crypto.dsig.keyinfo;
29
30import javax.xml.crypto.Data;
31import javax.xml.crypto.URIReference;
32import javax.xml.crypto.URIReferenceException;
33import javax.xml.crypto.XMLCryptoContext;
34import javax.xml.crypto.XMLStructure;
35import javax.xml.crypto.dsig.Transform;
36import java.util.List;
37
38/**
39 * A representation of the XML <code>RetrievalMethod</code> element as
40 * defined in the <a href="http://www.w3.org/TR/xmldsig-core/">
41 * W3C Recommendation for XML-Signature Syntax and Processing</a>.
42 * A <code>RetrievalMethod</code> object is used to convey a reference to
43 * <code>KeyInfo</code> information that is stored at another location.
44 * The XML schema definition is defined as:
45 *
46 * <pre>
47 *   &lt;element name="RetrievalMethod" type="ds:RetrievalMethodType"/&gt;
48 *   &lt;complexType name="RetrievalMethodType"&gt;
49 *     &lt;sequence&gt;
50 *       &lt;element name="Transforms" type="ds:TransformsType" minOccurs="0"/&gt;
51 *     &lt;/sequence&gt;
52 *     &lt;attribute name="URI" type="anyURI"/&gt;
53 *     &lt;attribute name="Type" type="anyURI" use="optional"/&gt;
54 *   &lt;/complexType&gt;
55 * </pre>
56 *
57 * A <code>RetrievalMethod</code> instance may be created by invoking one of the
58 * {@link KeyInfoFactory#newRetrievalMethod newRetrievalMethod} methods
59 * of the {@link KeyInfoFactory} class, and passing it the URI
60 * identifying the location of the KeyInfo, an optional type URI identifying
61 * the type of KeyInfo, and an optional list of {@link Transform}s; for example:
62 * <pre>
63 *   KeyInfoFactory factory = KeyInfoFactory.getInstance("DOM");
64 *   RetrievalMethod rm = factory.newRetrievalMethod
65 *      ("#KeyValue-1", KeyValue.DSA_TYPE, Collections.singletonList(Transform.BASE64));
66 * </pre>
67 *
68 * @author Sean Mullan
69 * @author JSR 105 Expert Group
70 * @since 1.6
71 * @see KeyInfoFactory#newRetrievalMethod(String)
72 * @see KeyInfoFactory#newRetrievalMethod(String, String, List)
73 */
74public interface RetrievalMethod extends URIReference, XMLStructure {
75
76    /**
77     * Returns an {@link java.util.Collections#unmodifiableList unmodifiable
78     * list} of {@link Transform}s of this <code>RetrievalMethod</code>.
79     *
80     * @return an unmodifiable list of <code>Transform</code> objects (may be
81     *    empty but never <code>null</code>).
82     */
83    List<Transform> getTransforms();
84
85    /**
86     * Returns the URI of the referenced <code>KeyInfo</code> information.
87     *
88     * @return the URI of the referenced <code>KeyInfo</code> information in
89     *    RFC 2396 format (never <code>null</code>)
90     */
91    String getURI();
92
93   /**
94    * Dereferences the <code>KeyInfo</code> information referenced by this
95    * <code>RetrievalMethod</code> and applies the specified
96    * <code>Transform</code>s.
97    *
98    * @param context an <code>XMLCryptoContext</code> that may contain
99    *    additional useful information for dereferencing the URI. The
100    *    context's <code>baseURI</code> and <code>dereferencer</code>
101    *    parameters (if specified) are used to resolve and dereference this
102    *    <code>RetrievalMethod</code>
103    * @return a <code>Data</code> object representing the raw contents of the
104    *    <code>KeyInfo</code> information referenced by this
105    *    <code>RetrievalMethod</code>. It is the caller's responsibility to
106    *    convert the returned data to an appropriate
107    *    <code>KeyInfo</code> object.
108    * @throws NullPointerException if <code>context</code> is <code>null</code>
109    * @throws URIReferenceException if there is an error while dereferencing
110    */
111    Data dereference(XMLCryptoContext context) throws URIReferenceException;
112}
113