Source for gnu.java.rmi.server.RMIHashes

   1: /* RMIHashes.java --
   2:    Copyright (c) 1996, 1997, 1998, 1999, 2004  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.java.rmi.server;
  40: 
  41: import gnu.java.lang.CPStringBuilder;
  42: 
  43: import gnu.java.lang.reflect.TypeSignature;
  44: 
  45: import java.io.ByteArrayOutputStream;
  46: import java.io.DataOutputStream;
  47: import java.lang.reflect.Method;
  48: import java.security.MessageDigest;
  49: 
  50: public class RMIHashes
  51: {
  52:   //There're other places using DigestOutputStream to generate hash in classpath, but I think the way I used
  53:   //here is more efficient, anyway, you can switch to DigestOutputStream by doing like "//or:" comments say.
  54: 
  55:   //or:add this statement: private static final NullOutputStream nullOutputStream = new NullOutputStream ();
  56:   public static long getMethodHash(Method meth)
  57:   {
  58:     //Object Serialization Spec 8.3
  59:     try
  60:     {
  61:         MessageDigest md = MessageDigest.getInstance ("SHA");
  62:         //or:remove this statement: DigestOutputStream digest_out = new DigestOutputStream (nullOutputStream, md);
  63:         ByteArrayOutputStream digest_out = new ByteArrayOutputStream();
  64:         DataOutputStream data_out = new DataOutputStream (digest_out);
  65: 
  66:         CPStringBuilder sbuf = new CPStringBuilder();
  67:         sbuf.append(meth.getName());
  68:         sbuf.append('(');
  69:         Class params[] = meth.getParameterTypes();
  70:         for(int i = 0; i < params.length; i++)
  71:             sbuf.append(TypeSignature.getEncodingOfClass(params[i]));
  72:         sbuf.append(')');
  73:         Class rcls = meth.getReturnType();
  74:         if(rcls != Void.TYPE)
  75:             sbuf.append(TypeSignature.getEncodingOfClass(rcls));
  76:         else
  77:             sbuf.append('V');
  78: 
  79:         data_out.writeUTF (sbuf.toString());
  80:         data_out.flush();
  81:         data_out.close ();
  82: 
  83:         md.update(digest_out.toByteArray()); //or:remove this statement
  84:         byte[] sha = md.digest ();
  85:         long result = 0;
  86:         int len = sha.length < 8 ? sha.length : 8;
  87:         for (int i=0; i < len; i++)
  88:             result += (long)(sha[i] & 0xFF) << (8 * i);
  89:         return result;
  90:     }catch(Exception _){
  91:         return -1L;
  92:         }
  93:   }
  94: 
  95:   public static long getInterfaceHash(Class clazz)
  96:   {
  97:     return clazz.hashCode ();
  98:   }
  99: }