1 /* 2 * Copyright (c) 2007, 2013, 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 package java.security.cert; 27 28 import java.io.IOException; 29 import java.io.OutputStream; 30 import java.io.Serializable; 31 32 /** 33 * This interface represents an X.509 extension. 34 * 35 * <p> 36 * Extensions provide a means of associating additional attributes with users 37 * or public keys and for managing a certification hierarchy. The extension 38 * format also allows communities to define private extensions to carry 39 * information unique to those communities. 40 * 41 * <p> 42 * Each extension contains an object identifier, a criticality setting 43 * indicating whether it is a critical or a non-critical extension, and 44 * and an ASN.1 DER-encoded value. Its ASN.1 definition is: 45 * 46 * <pre> 47 * 48 * Extension ::= SEQUENCE { 49 * extnId OBJECT IDENTIFIER, 50 * critical BOOLEAN DEFAULT FALSE, 51 * extnValue OCTET STRING 52 * -- contains a DER encoding of a value 53 * -- of the type registered for use with 54 * -- the extnId object identifier value 55 * } 56 * 57 * </pre> 58 * 59 * <p> 60 * This interface is designed to provide access to a single extension, 61 * unlike {@link java.security.cert.X509Extension} which is more suitable 62 * for accessing a set of extensions. 63 * 64 * @since 1.7 65 */ 66 public interface Extension { 67 68 /** 69 * Gets the extensions's object identifier. 70 * 71 * @return the object identifier as a String 72 */ getId()73 String getId(); 74 75 /** 76 * Gets the extension's criticality setting. 77 * 78 * @return true if this is a critical extension. 79 */ isCritical()80 boolean isCritical(); 81 82 /** 83 * Gets the extensions's DER-encoded value. Note, this is the bytes 84 * that are encoded as an OCTET STRING. It does not include the OCTET 85 * STRING tag and length. 86 * 87 * @return a copy of the extension's value, or {@code null} if no 88 * extension value is present. 89 */ getValue()90 byte[] getValue(); 91 92 /** 93 * Generates the extension's DER encoding and writes it to the output 94 * stream. 95 * 96 * @param out the output stream 97 * @exception IOException on encoding or output error. 98 * @exception NullPointerException if {@code out} is {@code null}. 99 */ encode(OutputStream out)100 void encode(OutputStream out) throws IOException; 101 } 102