net.agmodel.brokerImpl
Interface DBAccessMechanism

All Known Subinterfaces:

MetAccessMechanism

All Known Implementing Classes:

Amedas, CliDB, ClimDBApacheSOAP, FAWNMetDB, FieldServer, FilePerStationPerYear2, GAEMNHTML, Hitsujigaoka, HortPlus, HRI, JDBC, Kanagawa, Mamedas, PAWS, Planteforsk, PrefMetDB, SASA, SNUWDMS, TERN, WakayamaRainDB

public interface DBAccessMechanism

Defines general operations on a database.
Separate methods are used for connections for data and metadata because in a number of cases these are stored on different machines in different formats.

Author:

Matthew Laurenson

Method Summary

void	checkForDatabaseUpdates() connect to database and check the metadata
boolean	connectForData(String username, String password) Called before data is retrieved from the AccessMechanism
boolean	connectForMetaData(String username, String password) Called before metadata is retrieved from the AccessMechanism
void	disconnectFromData() Called after data is retrieved from the AccessMechanism using connectForData.
void	disconnectFromMetaData() Called after meta data is retrieved from the AccessMechanism using connectForMetaData.

Method Detail

connectForData

public boolean connectForData(String username,
                              String password)
                       throws ConnectionException

Called before data is retrieved from the AccessMechanism

Parameters:

username - a valid username for the database if it requires it, or null otherwise.

password - the corresponding password (not encrypted) if required, or null otherwise.

Returns:

true if the connection was established, false otherwise

Throws:

ConnectionException - if a connection could not be established

disconnectFromData

public void disconnectFromData()
                        throws ConnectionException

Called after data is retrieved from the AccessMechanism using connectForData.

Throws:

ConnectionException - if a connection could not be disconnected

connectForMetaData

public boolean connectForMetaData(String username,
                                  String password)
                           throws ConnectionException

Called before metadata is retrieved from the AccessMechanism

Parameters:

username - a valid username for the database if it requires it, or null otherwise.

password - the corresponding password (not encrypted) if required, or null otherwise.

Returns:

true if the connection was established, false otherwise

Throws:

ConnectionException - if a connection could not be established

disconnectFromMetaData

public void disconnectFromMetaData()
                            throws ConnectionException

Called after meta data is retrieved from the AccessMechanism using connectForMetaData.

Throws:

ConnectionException - if a connection could not be disconnected

checkForDatabaseUpdates

public void checkForDatabaseUpdates()
                             throws ConnectionException

connect to database and check the metadata

Throws:

ConnectionException