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Class tc.database.DatabaseManager

java.lang.Object
   |
   +----tc.database.DatabaseManager

public class DatabaseManager

extends Object

implements ExceptionObserver

DatabaseManager stores the user name and id and marker ids of the user for whom the database is opened (via this manager). These attributes are obtained during database opening and marker fetching and they are later used to ensure that only data associated with this user is tampered via this manager.

The interface ExceptionObserver (namely the operation exceptionOccured) is implemented so that it closes the database. This mechanism is used in exception situations.

Version:

0.30, 1998/04/01

Author:

Antti Viljamaa, FRED development team

See Also:

ExceptionObserver

connectionDescriptor

The connection descriptor for the database.

database

The database.

databaseOpen

Determines whether the database is open.

databaseStarted

Determines whether the database was succesfully started.

databaseStartException

The possible exception that occured upon a failed database start.

markerIDs

Vector of marker ids of the user.

userID

The user id (ssn) of the user.

userName

The user name of the user.

DatabaseManager()

Constructs a new DatabaseManager object and tries to start it.

closeDatabase()

Closes the database.

createDataSet(String, boolean)

Creates a new QueryDataSet and executes the specified query to fill it.

exceptionOccured(Exception)

An exception has occured during message sending or receiving.

getConnectionDescriptor()

Returns connection descriptor for the database.

getDatabase()

Returns the database.

getDatabaseStartException()

Gets the possible exception occured during database starting.

getMarkerIDs()

Returns the marker ids of the user.

getUserID()

Gets the user id.

getUserName()

Gets the username.

isDatabaseOpen()

Determines if the database is opened.

isDatabaseStarted()

Determines whether the database is started.

isValidMarker(int)

Determines if the specified marker is valid.

openDatabase(String, byte[])

Opens the database and returns the account options associated with the given userName.

runQuery(DatabaseQuery)

Executes the given query.

setConnectionDescriptor(ConnectionDescriptor)

Sets connection descriptor for the database.

setDatabaseOpen(boolean)

Sets the flag that determines if the database is opened.

setDatabaseStarted(boolean)

Sets the flag that determines whether the database is started.

setDatabaseStartException(Exception)

Sets the possible exception occured during database starting.

setMarkerIDs(Vector)

Sets the marker ids of the user.

setUserID(String)

Sets the user id.

setUserName(String)

Sets the username.

startDatabaseManager()

Starts the database.

trunc(long)

Truncates last three digits from a long integer.

 private Database database

The database.

 private boolean databaseOpen

Determines whether the database is open.

 private boolean databaseStarted

Determines whether the database was succesfully started.

 private Exception databaseStartException

The possible exception that occured upon a failed database start.

 private Vector markerIDs

Vector of marker ids of the user.

 private String userID

The user id (ssn) of the user. The key in the 'Worker' table.

 private String userName

The user name of the user. The key in the 'UserAccount' table.

 private ConnectionDescriptor connectionDescriptor

The connection descriptor for the database.

 public DatabaseManager()

Constructs a new DatabaseManager object and tries to start it. A possible exception that occurs is stored and later thrown when the openDatabase method is invoked.

See Also:

openDatabase

 public void closeDatabase() throws DataSetException, DatabaseAlreadyClosedException

Closes the database.

 public void exceptionOccured(Exception exception)

An exception has occured during message sending or receiving. We assume that connection to the client has terminated. Closes the database.

This method is the implementation for ExceptionObserver interface.

Parameters:

exception - The exception that has occured.

See Also:

ExceptionObserver

 public Vector getMarkerIDs()

Returns the marker ids of the user.

 public String getUserID()

Gets the user id.

 public String getUserName()

Gets the username.

 public boolean isDatabaseOpen()

Determines if the database is opened.

 public boolean isDatabaseStarted()

Determines whether the database is started.

 public AccountOptionsMessage openDatabase(String userName,
                                           byte passwd[]) throws Exception

Opens the database and returns the account options associated with the given userName. Checks that the given encrypted password matches the one in the database.

Parameters:

userName - The user whose data is going to be examined (and altered).

passwd - The encrypted password of the user.

 public Object runQuery(DatabaseQuery query) throws ValidationException, DataSetException

Executes the given query.

Parameters:

DatabaseQuery - The query to be executed.

Returns:

Object The query result.

 public ConnectionDescriptor getConnectionDescriptor()

Returns connection descriptor for the database.

 public void setConnectionDescriptor(ConnectionDescriptor cd)

Sets connection descriptor for the database.

 protected Database getDatabase()

Returns the database.

 protected Exception getDatabaseStartException()

Gets the possible exception occured during database starting.

 protected boolean isValidMarker(int markerid)

Determines if the specified marker is valid. Marker id is valid if it is found among the markers calculated for the user.

Parameters:

markerid - The marker id that is checked.

 protected void setDatabaseOpen(boolean flag)

Sets the flag that determines if the database is opened.

 protected void setDatabaseStarted(boolean flag)

Sets the flag that determines whether the database is started.

 protected void setUserID(String id)

Sets the user id.

 protected void setUserName(String n)

Sets the username.

 private QueryDataSet createDataSet(String queryClause,
                                    boolean updatable) throws DataSetException

Creates a new QueryDataSet and executes the specified query to fill it.

Parameters:

queryClause - An SQL query as a string.

updatable - Determines if the dataset to be created must be updatable (used in insertion or deletion).

Returns:

QueryDataSet The created data set.

 private void setDatabaseStartException(Exception e)

Sets the possible exception occured during database starting.

 private void setMarkerIDs(Vector v)

Sets the marker ids of the user.

 private void startDatabaseManager() throws DataSetException, ValidationException

Starts the database.

 static long trunc(long original)

Truncates last three digits from a long integer.

Parameters:

original - The original value.

Returns:

long The truncated value.

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