UserPasswords.java

package dmg.util ;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Hashtable;
import java.util.StringTokenizer;

public class UserPasswords extends Hashtable<String,Object> {
   private static final long serialVersionUID = -8781008473808464719L;
   private File _passwdFile;
   private long _updateTime;
   public UserPasswords( File passwdFile ){
      _passwdFile = passwdFile ;
   }
   @Override
   public String toString(){ return _passwdFile.getPath() ; }
   public String getPassword( String user ){
      String [] s = (String [])super.get( user ) ;
      return s == null ? null : s[1] ;
   }
   public String [] getRecord( String user ){
      return (String [] )super.get( user ) ;
   }
   public void removeRecord( String user ){
      super.remove( user ) ;
   }
   public void addRecord( String [] record ){
      if( ( record.length < 2 ) || ( record[0] == null ) || ( record[1] == null ) ) {
          throw new
                  IllegalArgumentException("Record [].length < 2");
      }
      super.put( record[0] , record ) ;
   }
   public void commit() throws IOException {

       if( _passwdFile == null ) {
           return;
       }

       String p = _passwdFile.getParent() ;
       p = p == null ? "." : p ;
       File   pwdFile = new File(p , '.' + _passwdFile.getName() ) ;
       PrintWriter pw = new PrintWriter(
                         new FileWriter( pwdFile ) ) ;
       try{
           for (Object o : values()) {
               Object[] a = (Object[]) o;
               for (int i = 0; (i < a.length) && (a[i] != null); i++) {
                   pw.print(a[i].toString() + ':');
               }
               pw.println("");
           }
       }catch(Exception xx){
          try{ pw.close() ; }catch(Exception ee ){}
          pwdFile.delete() ;
       }
       try{ pw.close() ; }catch(Exception ee ){}
       pwdFile.renameTo( _passwdFile ) ;
       _updateTime = _passwdFile.lastModified() ;
   }
   public void update() throws IOException {
      if( _passwdFile.exists()) {
          if( _updateTime > _passwdFile.lastModified() ) {
              return;
          }
          InputStream stream = new FileInputStream( _passwdFile ) ;
          try{
              _scanStream( stream ) ;
              _updateTime = _passwdFile.lastModified() ;
          }finally{
              try{ stream.close() ; }catch(Exception ee ){}
          }
      }
   }
   public void _scanStream( InputStream in ) throws IOException {

      BufferedReader reader = new BufferedReader(
                               new InputStreamReader( in ) ) ;
      String line ;
      while( ( line = reader.readLine() ) != null ){
         if( line.length() <= 0 ) {
             continue;
         }
         if( line.charAt(0) == '#' ) {
             continue;
         }
         StringTokenizer st = new StringTokenizer( line , ":" ) ;
         String [] a = new String[8] ;
         int i;
         for( i = 0 ; ( i < a.length ) && st.hasMoreTokens() ; i++ ){
            a[i] = st.nextToken() ;
         }
         if( i < 2 ) {
             continue;
         }
         put( a[0] , a ) ;
      }

   }
   //
   // to be complient
   //
   public UserPasswords( InputStream in ) throws IOException {
      super() ;
      _scanStream( in ) ;
   }
   @Override
   public Object get( Object key ){
       Object x = super.get(key) ;
       if( ( x == null                    ) ||
           ( ! ( x instanceof Object [] ) ) ||
           ( ((Object[])x).length < 2     )    ) {
           return null;
       }
       return ((Object[])x)[1] ;
   }
   public static void main( String [] args )throws Exception {
      if( args.length < 3 ){
        System.err.println("Usage : ... <filename> ( put user passwd ... ) | get user" ) ;
        System.exit(4);
      }
      String filename = args[0] ;
      String command  = args[1] ;
      String user     = args[2] ;
      UserPasswords ups = new UserPasswords( new File(filename) ) ;

       switch (command) {
       case "put": {

           String[] record = new String[args.length - 2];
           System.arraycopy(args, 2, record, 0, record.length);
           ups.addRecord(record);
           ups.commit();
           break;
       }
       case "get": {
           ups.update();
           String[] record = ups.getRecord(user);
           if (record == null) {
               System.out.println("Record not found for : " + user);
               System.exit(4);
           }
           for (int i = 0; (i < record.length) && (record[i] != null); i++) {
               System.out.print(record[i] + ' ');
           }
           System.out.println("");
           break;
       }
       default:
           System.err
                   .println("Usage : ... <filename> ( put user passwd ... ) | get user");
           System.exit(4);
       }
      System.exit(0);
   }
}