admin

Class UserDB

java.lang.Object

admin.UserDB

public abstract class UserDB
extends java.lang.Object

UserDB is the repository of registered user information. It is derived from

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	UserDB.SE1
class	UserDB.SE2

Field Summary

Fields

Modifier and Type	Field and Description
(package private) java.util.Collection<UserRecord>	data The collection of user data records.
(package private) GroupDB	groupDB Reference to GroupDB needed for change and delete methods.

Constructor Summary

Constructors

Constructor and Description
UserDB()

Method Summary

Methods

Modifier and Type	Method and Description
(package private) abstract void	add(UserRecord ur) Add the given UserRecord to the given UserDB.
(package private) abstract void	change(UserRecord old_ur, UserRecord new_ur) Change the given old UserRecord to the given new record.
(package private) abstract LeaderlessGroupsWarning	delete(UserRecord ur) Delete the given user record from the given UserDB.
(package private) abstract UserRecord	findById(java.lang.String id) Find a user by unique id.
(package private) abstract java.util.List<UserRecord>	findByName(java.lang.String name) Find a user or users by real-world name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

data

java.util.Collection<UserRecord> data

The collection of user data records.

groupDB

GroupDB groupDB

Reference to GroupDB needed for change and delete methods.

Constructor Detail

UserDB

public UserDB()

Method Detail

add

abstract void add(UserRecord ur)

Add the given UserRecord to the given UserDB. The Id of the given user record must not be the same as a user record already in the UserDB. The Id component is required and must be eight characters or less. The email address is required. The phone number is optional; if given, the area code and number must be 3 and 7 digits respectively.

      pre:
        //
        // There is no user record in the input UserDB with the same id as the
        // record to be added.
        //
        (! exists (UserRecord ur_other ;
                data.contains(ur_other) ;
                    ur_other.id.equals(ur.id)))

            &&

        //
        // The id of the given user record is not empty and 8 characters or
        // less.
        //
        (ur.id != null) && (ur.id.length() > 0) && (ur.id.length() <= 8)

            &&

        //
        // The email address is not empty.
        //
        (ur.email != null) && (ur.email.length() > 0)

            &&

        //
        // If the phone area code and number are present, they must be 3 digits
        // and 7 digits respectively.
        //
        ((ur.phone.area != 0) ==>
            Integer.toString(ur.phone.area).length() == 3) &&
        ((ur.phone.number != 0) ==>
            Integer.toString(ur.phone.number).length() == 7);

      post:
        //
        // A user record is in the output data if and only if it is the new
        // record to be added or it is in the input data.
        //
        forall (UserRecord ur_other ;
            (data'.contains(ur_other)) iff
                ur_other.equals(ur) || data.contains(ur_other));

findById

abstract UserRecord findById(java.lang.String id)

Find a user by unique id.

      post:
        //
        // If there is a record with the given id in the input data, then the
        // output record is equal to that record, otherwise the output record
        // is null.
        //
        exists (UserRecord ur_found ; data.contains(ur_found) ;
                ur_found.id.equals(id) && ur_found.equals(return))
            ||
        !exists (UserRecord ur_found ; data.contains(ur_found) ;
                ur_found.id.equals(id)) && return == null;

findByName

abstract java.util.List<UserRecord> findByName(java.lang.String name)

Find a user or users by real-world name. If more than one is found, the output list is sorted by id.

      post:
        //
        // The output list consists of all records of the given name in the
        // input data.
        //
        forall (UserRecord ur ;
            return.contains(ur) ;
                data.contains(ur) && ur.name.equals(name))

          &&

        //
        // The output list is sorted lexicographically by id, according to the
        // semantics of java.lang.String.compareTo().
        //
        forall (int i ; (i >= 0) && (i < return.size() - 1) ;
            return.get(i).id.compareTo(return.get(i+1).id) < 0);

change

abstract void change(UserRecord old_ur,
          UserRecord new_ur)

Change the given old UserRecord to the given new record. The old and new records must not be the same. The old record must already be in the input db. The new record must meet the same conditions as for the input to the AddUser operation. Typically the user runs the FindUser operation prior to Change to locate an existing record to be changed. If the user record id is changed, then change all occurrences of the old id in the group db to the new id.

      pre:
        //
        // The old and new user records are not the same.
        //
        !old_ur.equals(new_ur)

            &&

        //
        // The old record is in this.data.
        //
        data.contains(old_ur)

            &&

        //
        // There is no user record in the input UserDB with the same id as the
        // new record to be added.
        //
        (! exists (UserRecord ur_other ;
                data.contains(ur_other) ;
                    ur_other.id.equals(new_ur.id)))

            &&

        //
        // The id of the new record is not empty and 8 characters or less.
        //
        (new_ur.id != null) && (new_ur.id.length() > 0) &&
                (new_ur.id.length() <= 8)

            &&

        //
        // The email address is not empty.
        //
        (new_ur.email != null) && (new_ur.email.length() > 0)

            &&

        //
        // If the phone area code and number are present, they must be 3 digits
        // and 7 digits respectively.
        //
        ((new_ur.phone.area != 0) ==>
            Integer.toString(new_ur.phone.area).length() == 3) &&
        ((new_ur.phone.number != 0) ==>
            Integer.toString(new_ur.phone.number).length() == 7);

      post:
        //
        // A user record is in the output data if and only if it is the new
        // record to be added or it is in the input data, and it is not the old
        // record.
        //
        forall (UserRecord ur_other ;
            data'.contains(ur_other) iff
                ur_other.equals(new_ur) ||
                    (data.contains(ur_other) &&
                        !ur_other.equals(old_ur)))
            &&

        //
        // If new id is different than old id, then all occurrences of old id
        // in the GroupDB are replaced by new id.
        //
        !old_ur.id.equals(new_ur.id) ==> true
            // Logic left as exercise for the reader
                ;

delete

abstract LeaderlessGroupsWarning delete(UserRecord ur)

Delete the given user record from the given UserDB. The given record must already be in the input db. Typically the user runs the FindUser operation prior to Delete to locate an existing record to delete. In addition, delete the user from all groups of which the user is a member. If the deleted user is the only leader of a one more groups, output a warning indicating that those groups have become leaderless.

      pre:
        //
        // The given user record is in this.data.
        //
        data.contains(ur);

      post:
        //
        // A user record is in the output data if and only if it is not the
        // existing record to be deleted and it is in the input data.
        //
        forall (UserRecord ur_other ;
            data'.contains(ur_other) iff
                !ur_other.equals(ur) && data.contains(ur_other))

            &&

        //
        // The id of the deleted user is not in the leader or member lists of
        // any group in the output GroupDB.  (NOTE: This clause is not as
        // strong as a complete "no junk, no confusion" spec.  Why not?  Should
        // it be?)
        //
        forall (GroupRecord gr ; groupDB.data.contains(gr) ;
            !gr.leaders.contains(ur.id) && !gr.members.contains(ur.id))

            &&

        //
        // The LeaderlessGroupsWarning list contains the ids of all groups
        // whose only leader was the user who has just been deleted.
        //
        forall (GroupRecord gr ; groupDB.data.contains(gr) ;
            \forall String id ;
                (return.groupNames.contains(id) iff
                    gr.leaders.size() == 1) &&
                        (gr.leaders.get(0).equals(ur.id)));

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