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Diffstat (limited to 'gcc-4.4.3/libjava/classpath/gnu/java/security/Engine.java')
| -rw-r--r-- | gcc-4.4.3/libjava/classpath/gnu/java/security/Engine.java | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/gcc-4.4.3/libjava/classpath/gnu/java/security/Engine.java b/gcc-4.4.3/libjava/classpath/gnu/java/security/Engine.java new file mode 100644 index 000000000..6c39d46ac --- /dev/null +++ b/gcc-4.4.3/libjava/classpath/gnu/java/security/Engine.java @@ -0,0 +1,282 @@ +/* Engine -- generic getInstance method. + Copyright (C) 2003, 2006 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package gnu.java.security; + +import gnu.java.lang.CPStringBuilder; + +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; + +import java.security.NoSuchAlgorithmException; +import java.security.Provider; +import java.util.Enumeration; + +/** + * Generic implementation of the getInstance methods in the various + * engine classes in java.security. + * <p> + * These classes ({@link java.security.Signature} for example) can be + * thought of as the "chrome, upholstery, and steering wheel", and the SPI + * (service provider interface, e.g. {@link java.security.SignatureSpi}) + * classes can be thought of as the "engine" -- providing the actual + * functionality of whatever cryptographic algorithm the instance + * represents. + * + * @see Provider + * @author Casey Marshall + */ +public final class Engine +{ + + // Constants. + // ------------------------------------------------------------------------ + + /** Prefix for aliases. */ + private static final String ALG_ALIAS = "Alg.Alias."; + + /** Maximum number of aliases to try. */ + private static final int MAX_ALIASES = 5; + + /** Argument list for no-argument constructors. */ + private static final Object[] NO_ARGS = new Object[0]; + + // Constructor. + // ------------------------------------------------------------------------ + + /** This class cannot be instantiated. */ + private Engine() { } + + /** + * Return the implementation for <i>algorithm</i> for service <i>service</i> + * from <i>provider</i>. The service is e.g. "Signature", and the algorithm + * "DSA". + * + * @param service The service name. + * @param algorithm The name of the algorithm to get. + * @param provider The provider to get the implementation from. + * @return The engine class for the specified algorithm; the object returned + * is typically a subclass of the SPI class for that service, but + * callers should check that this is so. + * @throws NoSuchAlgorithmException If the implementation cannot be found or + * cannot be instantiated. + * @throws InvocationTargetException If the SPI class's constructor throws an + * exception. + * @throws IllegalArgumentException If any of the three arguments is null. + */ + public static Object getInstance(String service, String algorithm, + Provider provider) + throws InvocationTargetException, NoSuchAlgorithmException + { + return getInstance(service, algorithm, provider, NO_ARGS); + } + + /** + * Return the implementation for <i>algorithm</i> for service <i>service</i> + * from <i>provider</i>, passing <i>initArgs</i> to the SPI class's + * constructor (which cannot be null; pass a zero-length array if the SPI + * takes no arguments). The service is e.g. "Signature", and the algorithm + * "DSA". + * + * @param service The service name. + * @param algorithm The name of the algorithm to get. + * @param provider The provider to get the implementation from. + * @param initArgs The arguments to pass to the SPI class's constructor + * (cannot be null). + * @return The engine class for the specified algorithm; the object returned + * is typically a subclass of the SPI class for that service, but + * callers should check that this is so. + * @throws NoSuchAlgorithmException If the implementation cannot be found or + * cannot be instantiated. + * @throws InvocationTargetException If the SPI class's constructor throws an + * exception. + * @throws IllegalArgumentException If any of the four arguments is + * <code>null</code> or if either <code>service</code>, or + * <code>algorithm</code> is an empty string. + */ + public static Object getInstance(String service, String algorithm, + Provider provider, Object[] initArgs) + throws InvocationTargetException, NoSuchAlgorithmException + { + if (service == null) + throw new IllegalArgumentException("service MUST NOT be null"); + service = service.trim(); + if (service.length() == 0) + throw new IllegalArgumentException("service MUST NOT be empty"); + if (algorithm == null) + throw new IllegalArgumentException("algorithm MUST NOT be null"); + algorithm = algorithm.trim(); + if (algorithm.length() == 0) + throw new IllegalArgumentException("algorithm MUST NOT be empty"); + if (provider == null) + throw new IllegalArgumentException("provider MUST NOT be null"); + if (initArgs == null) + throw new IllegalArgumentException("Constructor's parameters MUST NOT be null"); + + Enumeration enumer = provider.propertyNames(); + String key = null; + String alias; + int count = 0; + boolean algorithmFound = false; + CPStringBuilder sb = new CPStringBuilder(); + while (enumer.hasMoreElements()) + { + key = (String) enumer.nextElement(); + if (key.equalsIgnoreCase(service + "." + algorithm)) + { + // remove the service portion from the key + algorithm = key.substring(service.length() + 1); + algorithmFound = true; + break; + } + else if (key.equalsIgnoreCase(ALG_ALIAS + service + "." + algorithm)) + { + alias = provider.getProperty(key); + if (! algorithm.equalsIgnoreCase(alias)) // does not refer to itself + { + algorithm = alias; + if (count++ > MAX_ALIASES) + { + sb.append("Algorithm [").append(algorithm) + .append("] of type [").append(service) + .append("] from provider [").append(provider) + .append("] has too many aliases"); + throw new NoSuchAlgorithmException(sb.toString()); + } + // need to reset enumeration to now look for the alias + enumer = provider.propertyNames(); + } + } + } + + if (! algorithmFound) + { + sb.append("Algorithm [").append(algorithm).append("] of type [") + .append(service).append("] from provider [") + .append(provider).append("] is not found"); + throw new NoSuchAlgorithmException(sb.toString()); + } + + // Find and instantiate the implementation + Class clazz = null; + ClassLoader loader = provider.getClass().getClassLoader(); + Constructor constructor = null; + String className = provider.getProperty(key); + sb.append("Class [").append(className).append("] for algorithm [") + .append(algorithm).append("] of type [").append(service) + .append("] from provider [").append(provider).append("] "); + Throwable cause = null; + try + { + if (loader != null) + clazz = loader.loadClass(className); + else + clazz = Class.forName(className); + constructor = getCompatibleConstructor(clazz, initArgs); + return constructor.newInstance(initArgs); + } + catch (ClassNotFoundException x) + { + sb.append("cannot not be found"); + cause = x; + } + catch (IllegalAccessException x) + { + sb.append("cannot be accessed"); + cause = x; + } + catch (InstantiationException x) + { + sb.append("cannot be instantiated"); + cause = x; + } + catch (ExceptionInInitializerError x) + { + sb.append("cannot be initialized"); + cause = x; + } + catch (SecurityException x) + { + sb.append("caused a security violation"); + cause = x; + } + catch (NoSuchMethodException x) + { + sb.append("does not have/expose an appropriate constructor"); + cause = x; + } + + NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); + x.initCause(cause); + throw x; + } + + /** + * Find a constructor in the given class that can take the specified + * argument list, allowing any of which to be null. + * + * @param clazz The class from which to get the constructor. + * @param initArgs The argument list to be passed to the constructor. + * @return The constructor. + * @throws NoSuchMethodException If no constructor of the given class + * can take the specified argument array. + */ + private static Constructor getCompatibleConstructor(Class clazz, + Object[] initArgs) + throws NoSuchMethodException + { + Constructor[] c = clazz.getConstructors(); + outer:for (int i = 0; i < c.length; i++) + { + Class[] argTypes = c[i].getParameterTypes(); + if (argTypes.length != initArgs.length) + continue; + for (int j = 0; j < argTypes.length; j++) + { + if (initArgs[j] != null && + !argTypes[j].isAssignableFrom(initArgs[j].getClass())) + continue outer; + } + // If we reach this point, we know this constructor (c[i]) has + // the same number of parameters as the target parameter list, + // and all our parameters are either (1) null, or (2) assignable + // to the target parameter type. + return c[i]; + } + throw new NoSuchMethodException(); + } +} |