simpledatabase.java

java kerberos implementation

/*
  Simple Implementation of Kerberos protocol v5
  Copyright (C) 2003 Thia Yeo Ching ([e-mail])

  This program 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
  of the License, or (at your option) any later version.

  This program 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 this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
package SimpleKerberos.tool;


import java.io.*;

/**
 * General purpose database built using file system.
 * Each database is a directory.
 * Each record is a text file, and the file name is the ID.
 */
public class SimpleDatabase
{
  private static final String USER_HOME = "user.home";
  private static final String FILE_SEPARATOR = "file.separator";

  private String databaseName_;

  /**
   * @param dbName
   */
  public SimpleDatabase(String dbName)
  {
    databaseName_ = dbName;
  }

  public boolean create()
  {
    // always create under home dir
    String fullpathname = getHomeDirWithLastFileSeparator() + databaseName_;
    File db = new File(fullpathname);
    boolean exists = db.exists();
    if (!exists)
    {
      if (db.mkdir())
      {
        return true;
      }
    }

    return false;
  }

  public boolean exists()
  {
    // always create under home dir
    String fullpathname = getHomeDirWithLastFileSeparator() + databaseName_;
    File db = new File(fullpathname);
    return db.exists();
  }

  /**
   * Return data in the file
   * @param name name of the file
   * @return null if cannot find the name
   */
  public String select(String name)
  {

    String fullpathname = getFullName(name);
    File n = new File(fullpathname);
    if (n.exists())
    {
      try
      {
        BufferedReader in = new BufferedReader(new FileReader(n));
        String str;
        str = in.readLine();
        in.close();
        if (str != null)
        {
          return str;
        }
      }
      catch (IOException e)
      {
        e.printStackTrace();
      }

    }

    return null;

  }

  public boolean insert(String name, String data)
  {
    String fullpathname = getFullName(name);
    File n = new File(fullpathname);
    if (!n.exists())
    {
      try
      {
        if (n.createNewFile())
        {
          BufferedWriter out = new BufferedWriter(new FileWriter(n));
          // file contents will only be the hashed password
          out.write(data);
          out.close();
          return true;
        }
      }
      catch (IOException e)
      {
        e.printStackTrace();
      }
    }

    return false;
  }

  private String getFullName(String name)
  {
    return getDatabaseFullPath() + getFileSeparator() + name;
  }

  private String getDatabaseFullPath()
  {
    return getHomeDirWithLastFileSeparator() + databaseName_;
  }

  private String getHomeDirWithLastFileSeparator()
  {
    return System.getProperty(USER_HOME) +
      getFileSeparator();
  }

  private String getFileSeparator()
  {
    return System.getProperty(FILE_SEPARATOR);
  }


}