Example: FileRegistrySample.java file (Version 5.0.2 and later)

import com.ibm.websphere.security.cred.*;
//
// 5639-D57, 5630-A36, 5630-A37, 5724-D18
// (C) COPYRIGHT International Business Machines Corp. 1997, 2003
// All Rights Reserved * Licensed Materials - Property of IBM
//

//----------------------------------------------------------------------
// This program may be used, executed, copied, modified and distributed 
// without royalty for the purpose of developing, using, marketing, or 
// distributing.
//----------------------------------------------------------------------
// 

// This sample is for the Custom User Registry feature
// in WebSphere Application Server.

import java.util.*;
import java.io.*;
import java.security.cert.X509Certificate;
import com.ibm.websphere.security.*;

/**
 *  The main purpose of this sample is to demonstrate the use of the
 *  Custom Registry feature available in WebSphere Application Server.
 *  This sample is a file-based registry sample where the users and the
 *  groups information is listed in files (users.props and groups.props).
 *  As such simplicity and not the performance was a major factor behind
 *  this. This sample should be used only to get familiarized with this
 *  feature. An actual implementation of a realistic registry should
 *  consider various factors like performance, scalability, thread safety,
 *  and so on.
 **/
public class FileRegistrySample implements UserRegistry {

   private static String USERFILENAME = null;        
   private static String GROUPFILENAME = null;

   /** Default Constructor **/
   public FileRegistrySample() throws java.rmi.RemoteException {
   }

  /**
   * Initializes the registry. This method is called when creating the
   * registry.
   *
   * @param     props   the registry-specific properties with which to
   *                    initialize the  custom registry
   * @exception CustomRegistryException
   *                    if there is any registry specific problem
   **/
  public void initialize(java.util.Properties props)
         throws CustomRegistryException {
      try {
          /* try getting the USERFILENAME and the GROUPFILENAME from 
          * properties that are passed in (i.e from GUI).
          * These values should be set in the security center GUI in the
          * Special Custom Settings in the Custom User Registry section of
          * the Authentication panel.
          * For example: 
          * usersFile   c:/temp/users.props
          * groupsFile  c:/temp/groups.props
          */
          if (props != null) {
             USERFILENAME = props.getProperty("usersFile");
             GROUPFILENAME = props.getProperty("groupsFile");
          }

      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      }

      if (USERFILENAME == null || GROUPFILENAME == null) {
         throw new CustomRegistryException("users/groups information missing");
      }

   }

  /**
   * Checks the password of the user. This method is called to authenticate a
   * user when the user's name and password are given.
   *
   * @param      userSecurityName the name of user
   * @param      password the password of the user
   * @return       a valid userSecurityName. Normally this is
   *               the name of same user whose password was checked but
   *               if the implementation wants to return any other valid
   *               userSecurityName in the registry it can do so
   * @exception CheckPasswordFailedException if userSecurityName/
   *                   password combination does not exist in the registry
   * @exception CustomRegistryException if there is any registry specific
   *                    problem
   **/
   public String checkPassword(String userSecurityName, String passwd) 
      throws PasswordCheckFailedException,
             CustomRegistryException {
      String s,userName = null;
      BufferedReader in = null;
    
      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.indexOf(":",index+1);
               // check if the userSecurityName:passwd combination exists
               if ((s.substring(0,index)).equals(userSecurityName) && 
                       s.substring(index+1,index1).equals(passwd)) {
                  // Authentication successful, return the userId.
                  userName = userSecurityName;
                  break;
               }
            }
         }
      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }
       

      if (userName == null) {
         throw new PasswordCheckFailedException("Password check failed for user: "
                                                + userSecurityName);
      } 

      return userName;
   }

  /**
   * Maps a X.509 format certificate to a valid user in the registry.
   * This is used to map the name in the certificate supplied by a browser
   * to a valid userSecurityName in the registry
   *
   * @param      cert the X509 certificate chain
   * @return      The mapped name of the user userSecurityName
   * @exception CertificateMapNotSupportedException if the particular
   *                    certificate is not supported.
   * @exception CertificateMapFailedException if the mapping of the
   *                    certificate fails.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public String mapCertificate(X509Certificate[] cert)
      throws CertificateMapNotSupportedException,
             CertificateMapFailedException,
             CustomRegistryException {
      String name=null;
      X509Certificate cert1 = cert[0];
      try {
         // map the SubjectDN in the certificate to a userID.
         name = cert1.getSubjectDN().getName();
      } catch(Exception ex) {
         throw new CertificateMapNotSupportedException(ex.getMessage(),ex);
      }

      if(!isValidUser(name)) {
         throw new CertificateMapFailedException("user: " + name + " is not valid");
      }
      return name;
   }

  /**
   * Returns the realm of the registry.
   *
   * @return       the realm. The realm is a registry-specific string indicating
   *               the realm or domain 
   *               for which this registry applies.  For example, for OS/400 or AIX 
   *               this would be the host name of the system whose user registry 
   *               this object represents.
   *               If null is returned by this method, realm defaults to the
   *               value of "customRealm".
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public String getRealm()
      throws CustomRegistryException {
      String name = "customRealm";
      return name;
   }

  /**
   * Gets a list of users that match a pattern in the registry.
   * The maximum number of users returned is defined by the limit
   * argument.
   * This method is called by GUI (administrative console) and scripting (command line)
   * to make the users in the registry available for adding them (users) to roles.
   *
   * @param      pattern the pattern to match. (For e.g., a* will match all
   *                    userSecurityNames starting with a)
   * @param      limit the maximum number of users that should be returned.
   *                    This is very useful in situations where there are thousands of
   *                    users in the registry and getting all of them at once is not
   *                    practical. The default is 100. A value of 0 implies get all the
   *                    users and hence must be used with care.
   * @return       a Result object that contains the list of users
   *                    requested and a flag to indicate if more users exist.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public Result getUsers(String pattern, int limit)
      throws CustomRegistryException {
      String s;
      BufferedReader in = null;
      List allUsers = new ArrayList();
      Result result = new Result();
      int count = 0;
      int newLimit = limit+1;
      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               String user = s.substring(0,index);
               if (match(user,pattern)) {
                  allUsers.add(user);
                  if (limit !=0 && ++count == newLimit) {
                     allUsers.remove(user);
                     result.setHasMore();
                     break;
                  }
               }
            }
         }
      } catch (Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      result.setList(allUsers);
      return result;
   }

  /**
   * Returns the display name for the user specified by userSecurityName.
   *
   * This method may be called only when the user information is displayed
   * ( information purposes only, for example, in GUI) and hence not used
   * in the actual authentication or authorization purposes. If there are no
   * display names in the registry return null or empty string.
   *
   * In WebSphere Application Server 4.0 custom registry, if you had a display
   * name for the user and if it was different from the security name, the
   * display name was returned for the EJB methods getCallerPrincipal() and
   * the servlet methods getUserPrincipal() and  getRemoteUser(). In WebSphere
   * Application Server Version 5, for the same methods, the security name is
   * returned by default. This is the recommended way as the display name is
   * not unique and may create security holes.
   * However, for backward compatability if one needs the display name to
   * be returned set the property WAS_UseDisplayName to true.
   *
   *See the Infocenter documentation for more information.
   *
   * @param     userSecurityName the name of the user.
   * @return      the display name for the user. The display name
   *              is a registry-specific string that represents a descriptive, not
   *              necessarily unique, name for a user. If a display name does
   *              not exist return null or empty string.
   * @exception EntryNotFoundException if userSecurityName does not exist.
   * @exception CustomRegistryException if there is any registry specific
   *                    problem
   **/
   public String getUserDisplayName(String userSecurityName)
      throws CustomRegistryException,
             EntryNotFoundException {

      String s,displayName = null;
      BufferedReader in = null;

      if(!isValidUser(userSecurityName)) {
         EntryNotFoundException nsee = new EntryNotFoundException("user: "
             + userSecurityName
             + " is not valid");
         throw nsee;
      }

      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.lastIndexOf(":");
               if ((s.substring(0,index)).equals(userSecurityName)) {
                  displayName = s.substring(index1+1);
                  break;
               }
            }
         }
      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(), ex);
      } finally {
         fileClose(in);
      }

      return displayName;
   }

  /**
   * Returns the unique ID for a userSecurityName. This method is called when
   * creating a credential for a user.
   *
   * @param      userSecurityName the name of the user.
   * @return       the unique ID of the user. The unique ID for an user is
   *                    the stringified form of some unique, registry-specific, data
   *                    that serves to represent the user.  For example, for the UNIX
   *                    user registry, the unique ID for a user can be the UID.
   * @exception EntryNotFoundException if userSecurityName does not exist.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public String getUniqueUserId(String userSecurityName)
      throws CustomRegistryException, 
             EntryNotFoundException {

      String s,uniqueUsrId = null;
      BufferedReader in = null;
      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.indexOf(":", index+1);
               if ((s.substring(0,index)).equals(userSecurityName)) {
                  int index2 = s.indexOf(":", index1+1);
                  uniqueUsrId = s.substring(index1+1,index2);
                  break;
               }
            }
         }
      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      if (uniqueUsrId == null) {
         EntryNotFoundException nsee =
             new EntryNotFoundException("Cannot obtain uniqueId for user: "
                 + userSecurityName);
         throw nsee;
      }

      return uniqueUsrId;
   }

  /**
   * Returns the name for a user given its uniqueId.
   *
   * @param      uniqueUserId  the unique ID of the user.
   * @return       The userSecurityName of the user.
   * @exception  EntryNotFoundException if the unique user ID does not exist.
   * @exception  CustomRegistryException if there is any registry-specific
   *                     problem
   **/
   public String getUserSecurityName(String uniqueUserId)
      throws CustomRegistryException,
             EntryNotFoundException {
      String s,usrSecName = null;
      BufferedReader in = null;
      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.indexOf(":", index+1);
               int index2 = s.indexOf(":", index1+1);
               if ((s.substring(index1+1,index2)).equals(uniqueUserId)) {
                  usrSecName = s.substring(0,index);
                  break;
               }
            }
         }
      } catch (Exception ex) {
         throw new CustomRegistryException(ex.getMessage(), ex);
      } finally {
         fileClose(in);
      }

      if (usrSecName == null) {
         EntryNotFoundException ex =
            new EntryNotFoundException("Cannot obtain the user securityName for "
             + uniqueUserId);
         throw ex;
      }

      return usrSecName;

   }

  /**
   * Determines if the userSecurityName exists in the registry
   *
   * @param      userSecurityName the name of the user
   * @return       true if the user is valid; otherwise false
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   * @exception RemoteException as this extends java.rmi.Remote
   **/
   public boolean isValidUser(String userSecurityName)
      throws CustomRegistryException {
      String s;
      boolean isValid = false;
      BufferedReader in = null;
      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               if ((s.substring(0,index)).equals(userSecurityName)) {
                  isValid=true;
                  break;
               }
            }
         }
      } catch (Exception ex) {
         throw new CustomRegistryException(ex.getMessage(), ex);
      } finally {
         fileClose(in);
      }

      return isValid;
   }


  /**
   * Gets a list of groups that match a pattern in the registy.
   * The maximum number of groups returned is defined by the limit
   * argument.
   * This method is called by GUI (administrative console) and scripting (command line)
   * to make available the groups in the registry for adding them (groups) to roles.
   *
   * @param       pattern the pattern to match. (For example, a * will match all
   *                     groupSecurityNames starting with a)
   * @param       limit the maximum number of groups that should be returned.
   *                    This is very useful in situations where there are thousands of
   *                    groups in the registry and getting all of them at once is not
   *                    practical. The default is 100. A value of 0 implies get all the
   *                    groups and hence must be used with care.
   * @return       a Result object that contains the list of groups
   *                    requested and a flag to indicate if more groups exist.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public Result getGroups(String pattern, int limit)
      throws CustomRegistryException {
      String s;
      BufferedReader in = null;
      List allGroups = new ArrayList();
      Result result = new Result();
      int count = 0;
      int newLimit = limit+1;
      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               String group = s.substring(0,index);
               if (match(group,pattern)) {
                  allGroups.add(group);
                  if (limit !=0 && ++count == newLimit) {
                     allGroups.remove(group);
                     result.setHasMore();
                     break;
                  }
               }
            }
         }
      } catch (Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }
  
      result.setList(allGroups);
      return result;
   }

  /**
   * Returns the display name for the group specified by groupSecurityName.
   * For this version of WebSphereApplication Server,  the only usage of this 
   * method is by the clients (GUI and Scripting) to present a descriptive name 
   * of the user if it exists.
   *
   * @param      groupSecurityName the name of the group.
   * @return     the display name for the group. The display name
   *             is a registry-specific string that represents a descriptive, not
   *             necessarily unique, name for a group. If a display name does
   *             not exist return null or empty string.
   * @exception EntryNotFoundException if groupSecurityName does not exist.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public String getGroupDisplayName(String groupSecurityName)
      throws CustomRegistryException,
             EntryNotFoundException {
      String s,displayName = null;
      BufferedReader in = null;

      if(!isValidGroup(groupSecurityName)) {
         EntryNotFoundException nsee = new EntryNotFoundException("group: "
             + groupSecurityName + " is not valid");
         throw nsee;
      }
      
      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.lastIndexOf(":");
               if ((s.substring(0,index)).equals(groupSecurityName)) {
                  displayName = s.substring(index1+1);
                  break;
               }
            }
         }
      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }
   
      return displayName;
   }

  /**
   * Returns the Unique id for a group.

   * @param      groupSecurityName the name of the group.
   * @return       the unique ID of the group. The unique ID for
   *                    a group is the stringified form of some unique,
   *                    registry-specific, data that serves to represent the group.
   *                    For example, for the UNIX user registry, the unique ID might
   *                    be the GID.
   * @exception EntryNotFoundException if groupSecurityName does not exist.
   * @exception CustomRegistryException if there is any registry specific
   *                    problem
   * @exception RemoteException as this extends java.rmi.Remote
   **/
   public String getUniqueGroupId(String groupSecurityName)
      throws CustomRegistryException,
             EntryNotFoundException {
      String s,uniqueGrpId = null;
      BufferedReader in = null;
      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.indexOf(":", index+1);
               if ((s.substring(0,index)).equals(groupSecurityName)) {
                  uniqueGrpId = s.substring(index+1,index1);
                  break;
               }
            }
         }
      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      if (uniqueGrpId == null) {
         EntryNotFoundException nsee =
            new EntryNotFoundException("Cannot obtain the uniqueId for group: "
             + groupSecurityName);
         throw nsee;
      }
      
      return uniqueGrpId;
   }

  /**
   * Returns the Unique ids for all the groups that contain the UniqueId of
   * a user. Called during creation of a user's credential.
   *
   * @param      uniqueUserId the unique ID of the user.
   * @return       a list of all the group unique IDs that the unique user ID
   *                    belongs to. The unique ID for an entry is the stringified
   *                    form of some unique, registry-specific, data that serves
   *                    to represent the entry.  For example, for the
   *                    UNIX user registry, the unique ID for a group might be the GID
   *                    and the Unique ID for the user might be the UID.
   * @exception EntryNotFoundException if uniqueUserId does not exist.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public List getUniqueGroupIds(String uniqueUserId)
      throws CustomRegistryException,
             EntryNotFoundException {
      String s,uniqueGrpId = null;
      BufferedReader in = null;
      List uniqueGrpIds=new ArrayList();
      try {
         in = fileOpen(USERFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.indexOf(":", index+1);
               int index2 = s.indexOf(":", index1+1);
               if ((s.substring(index1+1,index2)).equals(uniqueUserId)) {
                  int lastIndex = s.lastIndexOf(":");
                  String subs = s.substring(index2+1,lastIndex);
                  StringTokenizer st1 = new StringTokenizer(subs, ",");
                  while (st1.hasMoreTokens()) 
                     uniqueGrpIds.add(st1.nextToken());
                  break;
               }
            }
         }
      } catch(Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      return uniqueGrpIds;
   }

  /**
   * Returns the name for a group given its uniqueId.
   *
   * @param     uniqueGroupId the unique ID of the group.
   * @return      the name of the group.
   * @exception EntryNotFoundException if the uniqueGroupId does not exist.
   * @exception CustomRegistryException if there is any registry specific
   *                    problem
   **/
   public String getGroupSecurityName(String uniqueGroupId)
      throws CustomRegistryException,
             EntryNotFoundException {
      String s,grpSecName = null;
      BufferedReader in = null;
      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               int index1 = s.indexOf(":", index+1);
               if ((s.substring(index+1,index1)).equals(uniqueGroupId)) {
                  grpSecName = s.substring(0,index);
                  break;
               }
            }
         }
      } catch (Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      if (grpSecName == null) {
         EntryNotFoundException ex = 
            new EntryNotFoundException("Cannot obtain the group security name for: "
             + uniqueGroupId);
         throw ex;
      }

      return grpSecName;

   }

  /**
   * Determines if the groupSecurityName exists in the registry
   *
   * @param      groupSecurityName the name of the group
   * @return       true if the groups exists; otherwise false
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   **/
   public boolean isValidGroup(String groupSecurityName)
      throws CustomRegistryException {
      String s;
      boolean isValid = false;
      BufferedReader in = null;
      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               if ((s.substring(0,index)).equals(groupSecurityName)) {
                  isValid=true;
                  break;
               }
            }
         }
      } catch (Exception ex) {
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      return isValid;
   }

  /**
   * Returns the securityNames of all the groups that contain the user
   *
   * This method is called by GUI (administrative console) and scripting (command line)
   * to verify the user entered for RunAsRole mapping belongs to that role
   * in the roles to user mapping. Initially, the check is done to see if
   * the role contains the user. If the role does not contain the user
   * explicitly, this method is called to get the groups that this user
   * belongs to so that check can be made on the groups that the role contains.
   *
   * @param      userSecurityName the name of the user
   * @return       a list of all the group securityNames that the user
   *                    belongs to.
   * @exception EntryNotFoundException if user does not exist.
   * @exception CustomRegistryException if there is any registry-specific
   *                    problem
   * @exception RemoteException as this extends java.rmi.Remote
   **/
   public List getGroupsForUser(String userName)
      throws CustomRegistryException,
             EntryNotFoundException {
      String s;
      List grpsForUser = new ArrayList();
      BufferedReader in = null;
      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               StringTokenizer st = new StringTokenizer(s, ":");
               for (int i=0; i<2; i++)
                  st.nextToken();
               String subs = st.nextToken();
               StringTokenizer st1 = new StringTokenizer(subs, ",");
               while (st1.hasMoreTokens()) {
                  if((st1.nextToken()).equals(userName)) {
                     int index = s.indexOf(":");
                     grpsForUser.add(s.substring(0,index));
                  }
               }
            }
         }
      } catch (Exception ex) {
         if (!isValidUser(userName)) {
            throw new EntryNotFoundException("user: " + userName  + " is not valid");
         }
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      return grpsForUser;
   }

  /**
   * Gets a list of users in a group.  
   *
   * The maximum number of users returned is defined by the limit argument.
   *
   * In rare situations if you are working with a registry where getting all 
   * the users from any of your groups is not practical (for example if there 
   * are a large number of users) you can throw the NotImplementedException
   * for that particualar group(s). If there is no concern about 
   * returning the users from groups in the registry it is recommended that 
   * this method be implemented without throwing the NotImplemented exception.
   *
   * @param         groupSecurityName the name of the group
   * @param         limit the maximum number of users that should be returned.
   *                This is very useful in situations where there are lot of
   *                users in the registry and getting all of them at once is not
   *                practical. A value of 0 implies get all the users and hence 
   *                must be used with care. 
   * @return          a Result object that contains the list of users
   *                  requested and a flag to indicate if more users exist.
   * @deprecated  This method will be deprecated in future.
   * @exception     NotImplementedException throw this exception in rare situations
   *                if it is not pratical to get this information for any of the 
   *                group or groups from the registry.
   * @exception     EntryNotFoundException if the group does not exist in 
   *                        the registry
   * @exception     CustomRegistryException if there is any registry-specific 
   *                        problem
   **/
   public Result getUsersForGroup(String groupSecurityName, int limit)
      throws NotImplementedException,
             EntryNotFoundException,
             CustomRegistryException {
      String s, user;
      BufferedReader in = null;
      List usrsForGroup = new ArrayList();
      int count = 0;
      int newLimit = limit+1;
      Result result = new Result();

      try {
         in = fileOpen(GROUPFILENAME);
         while ((s=in.readLine())!=null)
         {
            if (!(s.startsWith("#") || s.trim().length() <=0 )) {
               int index = s.indexOf(":");
               if ((s.substring(0,index)).equals(groupSecurityName))
               {
                  StringTokenizer st = new StringTokenizer(s, ":");
                  for (int i=0; i<2; i++)
                     st.nextToken();
                  String subs = st.nextToken();
                  StringTokenizer st1 = new StringTokenizer(subs, ",");
                  while (st1.hasMoreTokens()) {
                     user = st1.nextToken();
                     usrsForGroup.add(user);
                     if (limit !=0 && ++count == newLimit) {
                        usrsForGroup.remove(user);
                        result.setHasMore();
                        break;
                     }
                  }
               }
            }
         }
      } catch (Exception ex) {
         if (!isValidGroup(groupSecurityName)) {
            throw new EntryNotFoundException("group: "
             + groupSecurityName 
             + " is not valid");
         }
         throw new CustomRegistryException(ex.getMessage(),ex);
      } finally {
         fileClose(in);
      }

      result.setList(usrsForGroup);
      return result;
   }

  /**
   * This method is implemented internally by the WebSphere Application Server code
   * in this release. This method is not called for the Custom Registry
   * implementations for this release. Return null in the implementation.
   *
   **/
   public WSCredential createCredential(String userSecurityName)
         throws CustomRegistryException,
                NotImplementedException,
                EntryNotFoundException {

      // This method is not called.
      return null;
   }

   // private methods
   private BufferedReader fileOpen(String fileName)
      throws FileNotFoundException {
      try {
         return new BufferedReader(new FileReader(fileName));
      } catch(FileNotFoundException e) {
         throw e;
      }
   }

   private void fileClose(BufferedReader in) {
      try {
         if (in != null) in.close();
      } catch(Exception e) {
         System.out.println("Error closing file" + e);
      }
   }

   private boolean match(String name, String pattern) {
      RegExpSample regexp = new RegExpSample(pattern);
      boolean matches = false;
      if(regexp.match(name))
          matches = true;
      return matches;
   }
}


//----------------------------------------------------------------------
// The program provides the Regular Expression implementation used in the
// Sample for the Custom User Registry (FileRegistrySample). The pattern 
// matching in the sample uses this program to search for the pattern (for
// users and groups).
//----------------------------------------------------------------------

class RegExpSample
{

    private boolean match(String s, int i, int j, int k)
    {
        for(; k < expr.length; k++)
label0:
            {
                Object obj = expr[k];
                if(obj == STAR)
                {
                    if(++k >= expr.length)
                        return true;
                    if(expr[k] instanceof String)
                    {
                        String s1 = (String)expr[k++];
                        int l = s1.length();
                        for(; (i = s.indexOf(s1, i)) >= 0; i++)
                            if(match(s, i + l, j, k))
                                return true;

                        return false;
                    }
                    for(; i < j; i++)
                        if(match(s, i, j, k))
                            return true;

                    return false;
                }
                if(obj == ANY)
                {
                    if(++i > j)
                        return false;
                    break label0;
                }
                if(obj instanceof char[][])
                {
                    if(i >= j)
                        return false;
                    char c = s.charAt(i++);
                    char ac[][] = (char[][])obj;
                    if(ac[0] == NOT)
                    {
                        for(int j1 = 1; j1 < ac.length; j1++)
                            if(ac[j1][0] <= c && c <= ac[j1][1])
                                return false;

                        break label0;
                    }
                    for(int k1 = 0; k1 < ac.length; k1++)
                        if(ac[k1][0] <= c && c <= ac[k1][1])
                            break label0;

                    return false;
                }
                if(obj instanceof String)
                {
                    String s2 = (String)obj;
                    int i1 = s2.length();
                    if(!s.regionMatches(i, s2, 0, i1))
                        return false;
                    i += i1;
                }
            }

        return i == j;
    }

    public boolean match(String s)
    {
        return match(s, 0, s.length(), 0);
    }

    public boolean match(String s, int i, int j)
    {
        return match(s, i, j, 0);
    }

    public RegExpSample(String s)
    {
        Vector vector = new Vector();
        int i = s.length();
        StringBuffer stringbuffer = null;
        Object obj = null;
        for(int j = 0; j < i; j++)
        {
            char c = s.charAt(j);
            switch(c)
            {
            case 63: /* '?' */
                obj = ANY;
                break;

            case 42: /* '*' */
                obj = STAR;
                break;

            case 91: /* '[' */
                int k = ++j;
                Vector vector1 = new Vector();
                for(; j < i; j++)
                {
                    c = s.charAt(j);
                    if(j == k && c == '^')
                    {
                        vector1.addElement(NOT);
                        continue;
                    }
                    if(c == '\\')
                    {
                        if(j + 1 < i)
                            c = s.charAt(++j);
                    }
                    else
                    if(c == ']')
                        break;
                    char c1 = c;
                    if(j + 2 < i && s.charAt(j + 1) == '-')
                        c1 = s.charAt(j += 2);
                    char ac1[] = {
                        c, c1
                    };
                    vector1.addElement(ac1);
                }

                char ac[][] = new char[vector1.size()][];
                vector1.copyInto(ac);
                obj = ac;
                break;

            case 92: /* '\\' */
                if(j + 1 < i)
                    c = s.charAt(++j);
                break;

            }
            if(obj != null)
            {
                if(stringbuffer != null)
                {
                    vector.addElement(stringbuffer.toString());
                    stringbuffer = null;
                }
                vector.addElement(obj);
                obj = null;
            }
            else
            {
                if(stringbuffer == null)
                    stringbuffer = new StringBuffer();
                stringbuffer.append(c);
            }
        }

        if(stringbuffer != null)
            vector.addElement(stringbuffer.toString());
        expr = new Object[vector.size()];
        vector.copyInto(expr);
    }

    static final char NOT[] = new char[2];
    static final Integer ANY = new Integer(0);
    static final Integer STAR = new Integer(1);
    Object expr[];

}