001/* CertPathBuilder.java -- bulids CertPath objects from Certificates. 002 Copyright (C) 2003, 2004 Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038 039package java.security.cert; 040 041import gnu.java.lang.CPStringBuilder; 042 043import gnu.java.security.Engine; 044 045import java.lang.reflect.InvocationTargetException; 046import java.security.InvalidAlgorithmParameterException; 047import java.security.NoSuchAlgorithmException; 048import java.security.NoSuchProviderException; 049import java.security.Provider; 050import java.security.Security; 051 052/** 053 * This class builds certificate paths (also called certificate chains), 054 * which can be used to establish trust for a particular certificate by 055 * building a path from a trusted certificate (a trust anchor) to the 056 * untrusted certificate. 057 * 058 * @see CertPath 059 */ 060public class CertPathBuilder 061{ 062 063 // Constants and fields. 064 // ------------------------------------------------------------------------ 065 066 /** Service name for CertPathBuilder. */ 067 private static final String CERT_PATH_BUILDER = "CertPathBuilder"; 068 069 /** The underlying implementation. */ 070 private CertPathBuilderSpi cpbSpi; 071 072 /** The provider of this implementation. */ 073 private Provider provider; 074 075 /** The name of this implementation. */ 076 private String algorithm; 077 078 // Constructor. 079 // ------------------------------------------------------------------------ 080 081 /** 082 * Creates a new CertPathBuilder. 083 * 084 * @param cpbSpi The underlying implementation. 085 * @param provider The provider of the implementation. 086 * @param algorithm This implementation's name. 087 */ 088 protected CertPathBuilder(CertPathBuilderSpi cpbSpi, Provider provider, 089 String algorithm) 090 { 091 this.cpbSpi = cpbSpi; 092 this.provider = provider; 093 this.algorithm = algorithm; 094 } 095 096 // Class methods. 097 // ------------------------------------------------------------------------ 098 099 /** 100 * Get the default cert path builder type. 101 * 102 * <p>This value can be set at run-time by the security property 103 * <code>"certpathbuilder.type"</code>. If this property is not set, 104 * then the value returned is <code>"PKIX"</code>. 105 * 106 * @return The default CertPathBuilder algorithm. 107 */ 108 public static final String getDefaultType() 109 { 110 String type = Security.getProperty("certpathbuilder.type"); 111 if (type == null) 112 type = "PKIX"; 113 return type; 114 } 115 116 /** 117 * Returns an instance of a named <code>CertPathBuilder</code> from the 118 * first provider that implements it. 119 * 120 * @param algorithm The name of the <code>CertPathBuilder</code> to create. 121 * @return The new instance. 122 * @throws NoSuchAlgorithmException If no installed provider implements the 123 * named algorithm. 124 * @throws IllegalArgumentException if <code>algorithm</code> is 125 * <code>null</code> or is an empty string. 126 */ 127 public static CertPathBuilder getInstance(String algorithm) 128 throws NoSuchAlgorithmException 129 { 130 Provider[] p = Security.getProviders(); 131 NoSuchAlgorithmException lastException = null; 132 for (int i = 0; i < p.length; i++) 133 try 134 { 135 return getInstance(algorithm, p[i]); 136 } 137 catch (NoSuchAlgorithmException x) 138 { 139 lastException = x; 140 } 141 if (lastException != null) 142 throw lastException; 143 throw new NoSuchAlgorithmException(algorithm); 144 } 145 146 /** 147 * Returns an instance of a named <code>CertPathBuilder</code> from a named 148 * provider. 149 * 150 * @param algorithm The name of the <code>CertPathBuilder</code> to create. 151 * @param provider The name of the provider to use. 152 * @return The new instance. 153 * @throws NoSuchAlgorithmException If no installed provider implements the 154 * named algorithm. 155 * @throws NoSuchProviderException If the named provider does not exist. 156 * @throws IllegalArgumentException if either <code>algorithm</code> or 157 * <code>provider</code> is <code>null</code>, or if 158 * <code>algorithm</code> is an empty string. 159 */ 160 public static CertPathBuilder getInstance(String algorithm, String provider) 161 throws NoSuchAlgorithmException, NoSuchProviderException 162 { 163 if (provider == null) 164 throw new IllegalArgumentException("provider MUST NOT be null"); 165 Provider p = Security.getProvider(provider); 166 if (p == null) 167 throw new NoSuchProviderException(provider); 168 return getInstance(algorithm, p); 169 } 170 171 /** 172 * Returns an instance of a named <code>CertPathBuilder</code> from the 173 * specified provider. 174 * 175 * @param algorithm The name of the <code>CertPathBuilder</code> to create. 176 * @param provider The provider to use. 177 * @return The new instance. 178 * @throws NoSuchAlgorithmException If no installed provider implements the 179 * named algorithm. 180 * @throws IllegalArgumentException if either <code>algorithm</code> or 181 * <code>provider</code> is <code>null</code>, or if 182 * <code>algorithm</code> is an empty string. 183 */ 184 public static CertPathBuilder getInstance(String algorithm, Provider provider) 185 throws NoSuchAlgorithmException 186 { 187 CPStringBuilder sb = new CPStringBuilder("CertPathBuilder for algorithm [") 188 .append(algorithm).append("] from provider[") 189 .append(provider).append("] could not be created"); 190 Throwable cause; 191 try 192 { 193 Object spi = Engine.getInstance(CERT_PATH_BUILDER, algorithm, provider); 194 return new CertPathBuilder((CertPathBuilderSpi) spi, provider, algorithm); 195 } 196 catch (InvocationTargetException x) 197 { 198 cause = x.getCause(); 199 if (cause instanceof NoSuchAlgorithmException) 200 throw (NoSuchAlgorithmException) cause; 201 if (cause == null) 202 cause = x; 203 } 204 catch (ClassCastException x) 205 { 206 cause = x; 207 } 208 NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); 209 x.initCause(cause); 210 throw x; 211 } 212 213 /** 214 * Return the name of this CertPathBuilder algorithm. 215 * 216 * @return The algorithm name. 217 */ 218 public final String getAlgorithm() 219 { 220 return algorithm; 221 } 222 223 /** 224 * Return the provider of this instance's implementation. 225 * 226 * @return The provider. 227 */ 228 public final Provider getProvider() 229 { 230 return provider; 231 } 232 233 /** 234 * Builds a certificate path. The {@link CertPathParameters} parameter 235 * passed to this method is implementation-specific, but in general 236 * should contain some number of certificates and some number of 237 * trusted certificates (or "trust anchors"). 238 * 239 * @param params The parameters. 240 * @retrun The certificate path result. 241 * @throws CertPathBuilderException If the certificate path cannot be 242 * built. 243 * @throws InvalidAlgorithmParameterException If the implementation 244 * rejects the specified parameters. 245 */ 246 public final CertPathBuilderResult build(CertPathParameters params) 247 throws CertPathBuilderException, InvalidAlgorithmParameterException 248 { 249 return cpbSpi.engineBuild(params); 250 } 251}