public JSch() 
{
    try{
      String osname=(String)(System.getProperties().get("os.name"));
      if(osname!=null && osname.equals("Mac OS X")){
        config.put("hmac-sha1",     "com.jcraft.jsch.jcraft.HMACSHA1"); 
        config.put("hmac-md5",      "com.jcraft.jsch.jcraft.HMACMD5"); 
        config.put("hmac-md5-96",   "com.jcraft.jsch.jcraft.HMACMD596"); 
        config.put("hmac-sha1-96",  "com.jcraft.jsch.jcraft.HMACSHA196"); 
      }
    }
    catch(Exception e){
    }
}

 public  void addIdentity(String prvkey) throws JSchException 
{
    addIdentity(prvkey, (byte[])null);
}

 public  void addIdentity(String prvkey,
    String passphrase) throws JSchException 
{
    byte[] _passphrase=null;
    if(passphrase!=null){
      _passphrase=Util.str2byte(passphrase);
    }
    addIdentity(prvkey, _passphrase);
    if(_passphrase!=null)
      Util.bzero(_passphrase);
}

 public  void addIdentity(String prvkey,
    byte[] passphrase) throws JSchException 
{
    Identity identity=IdentityFile.newInstance(prvkey, null, this);
    addIdentity(identity, passphrase);
}

 public  void addIdentity(Identity identity,
    byte[] passphrase) throws JSchException 
{
    if(passphrase!=null){
      try{ 
        byte[] goo=new byte[passphrase.length];
        System.arraycopy(passphrase, 0, goo, 0, passphrase.length);
        passphrase=goo;
        identity.setPassphrase(passphrase); 
      }
      finally{
        Util.bzero(passphrase);
      }
    }
    synchronized(identities){
      if(!identities.contains(identity)){
	identities.addElement(identity);
      }
    }
}

 public  void addIdentity(String prvkey,
    String pubkey,
    byte[] passphrase) throws JSchException 
{
    Identity identity=IdentityFile.newInstance(prvkey, pubkey, this);
    addIdentity(identity, passphrase);
}

 public  void addIdentity(String name,
    byte[] prvkey,
    byte[] pubkey,
    byte[] passphrase) throws JSchException 
{
    Identity identity=IdentityFile.newInstance(name, prvkey, pubkey, this);
    addIdentity(identity, passphrase);
}

 protected  void addSession(Session session) 
{
    synchronized(pool){
      pool.addElement(session);
    }
}

 public static String getConfig(String key) 
{
 
    synchronized(config){
      return (String)(config.get(key));
    }
}

 public HostKeyRepository getHostKeyRepository() 
{
 
    if(known_hosts==null) known_hosts=new KnownHosts(this);
    return known_hosts;
}

 public Vector getIdentityNames() throws JSchException 
{
    Vector foo=new Vector();
    synchronized(identities){
      for(int i=0; i< identities.size(); i++){
        Identity identity=(Identity)(identities.elementAt(i));
        foo.addElement(identity.getName());
      }
    }
    return foo;
}

 static Logger getLogger() 
{
    return logger;
}

 public Session getSession(String username,
    String host) throws JSchException 
{
 return getSession(username, host, 22);
}

 public Session getSession(String username,
    String host,
    int port) throws JSchException 
{
    if(username==null){
      throw new JSchException("username must not be null.");
    }
    if(host==null){
      throw new JSchException("host must not be null.");
    }
    Session s=new Session(this); 
    s.setUserName(username);
    s.setHost(host);
    s.setPort(port);
    //pool.addElement(s);
    return s;
}

 public  void removeAllIdentity() throws JSchException 
{
    synchronized(identities){
      Vector foo=getIdentityNames();
      for(int i=0; i< foo.size(); i++){
        String name=((String)foo.elementAt(i));
        removeIdentity(name);
      }
    }
}

 public  void removeIdentity(String name) throws JSchException 
{
    synchronized(identities){
      for(int i=0; i< identities.size(); i++){
        Identity identity=(Identity)(identities.elementAt(i));
	if(!identity.getName().equals(name))
          continue;
        identities.removeElement(identity);
        identity.clear();
        break;
      }
    }
}

 protected boolean removeSession(Session session) 
{
    synchronized(pool){
      return pool.remove(session);
    }
}

 public static  void setConfig(Hashtable newconf) 
{
    synchronized(config){
      for(java.util.Enumeration e=newconf.keys() ; e.hasMoreElements() ;) {
	String key=(String)(e.nextElement());
	config.put(key, (String)(newconf.get(key)));
      }
    }
}

 public static  void setConfig(String key,
    String value) 
{
    config.put(key, value);
}

 public  void setHostKeyRepository(HostKeyRepository hkrepo) 
{
    known_hosts=hkrepo;
}

 public  void setKnownHosts(String filename) throws JSchException 
{
    if(known_hosts==null) known_hosts=new KnownHosts(this);
    if(known_hosts instanceof KnownHosts){
      synchronized(known_hosts){
	((KnownHosts)known_hosts).setKnownHosts(filename); 
      }
    }
}

 public  void setKnownHosts(InputStream stream) throws JSchException 
{
 
    if(known_hosts==null) known_hosts=new KnownHosts(this);
    if(known_hosts instanceof KnownHosts){
      synchronized(known_hosts){
	((KnownHosts)known_hosts).setKnownHosts(stream); 
      }
    }
}

 public static  void setLogger(Logger logger) 
{
    if(logger==null) JSch.logger=DEVNULL;
    JSch.logger=logger;
}