uk.ac.ed.epcc.webapp.jdbc.config

Class DataBaseConfigService

java.lang.Object

uk.ac.ed.epcc.webapp.jdbc.config.DataBaseConfigService

All Implemented Interfaces:

AppContextCleanup, AppContextService<ConfigService>, ConfigService, Contexed

public class DataBaseConfigService
extends java.lang.Object
implements ConfigService

ConfigService that adds additional properties from a database table. This is a wrapper that decorates a previously installed ConfigService. The name of the table to store the properties is taken from a property database.properties from the nested service. If this property is not found then this service will just foward to the nested service. There is a nasty potential circular dependency where the DatabaseService needed to query the database table may need the ConfigService and may end up calling back to this class. during setup. This is particularly nasty if there is a CachedConfigService in the stack as we have to make sure that the cache does not end up holding state from before the DB is read or from a transient database error state.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	NAME
static java.lang.String	VALUE

Constructor Summary

Constructors

Constructor and Description
DataBaseConfigService(AppContext ctx)

Method Summary

Modifier and Type	Method and Description
void	addListener(ConfigServiceListener listener) register a ConfigServiceListener
void	cleanup() AppContext is being closed.
void	clearServiceProperties() clear any cached properties.
AppContext	getContext()
java.util.Properties	getServiceProperties() return the set of properties defined by the service
java.lang.Class<ConfigService>	getType() Returns the type of service the class should be registered under.
void	setProperty(java.lang.String name, java.lang.String value) Set a property This method is for making persistent changes to the configuration.

Methods inherited from class java.lang.Object

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

Field Detail

VALUE

public static final java.lang.String VALUE

See Also:

Constant Field Values

NAME

public static final java.lang.String NAME

See Also:

Constant Field Values

Constructor Detail

DataBaseConfigService

public DataBaseConfigService(AppContext ctx)
                      throws java.sql.SQLException

Throws:

java.sql.SQLException

Method Detail

clearServiceProperties

public void clearServiceProperties()

Description copied from interface: ConfigService

clear any cached properties. This will cause the properties to be re-read the next time getServiceProperties is called. Implementations are permitted not to cache data in which case this is a No-op.

Specified by:

clearServiceProperties in interface ConfigService

getServiceProperties

public java.util.Properties getServiceProperties()

Description copied from interface: ConfigService

return the set of properties defined by the service

Specified by:

getServiceProperties in interface ConfigService

Returns:

Properties

getContext

public AppContext getContext()

Specified by:

getContext in interface Contexed

setProperty

public void setProperty(java.lang.String name,
                        java.lang.String value)
                 throws java.lang.UnsupportedOperationException

Description copied from interface: ConfigService

Set a property This method is for making persistent changes to the configuration. if the service is not capable of making persistent changes it should forward the request to a nested service or throw an UnsupportedOperationException

Specified by:

setProperty in interface ConfigService

Throws:

java.lang.UnsupportedOperationException

cleanup

public void cleanup()

Description copied from interface: AppContextCleanup

AppContext is being closed. Only use this for cleanup that can't be handled by normal garbage collection or for state which is never returned by reference.

Specified by:

cleanup in interface AppContextCleanup

addListener

public void addListener(ConfigServiceListener listener)

Description copied from interface: ConfigService

register a ConfigServiceListener

Specified by:

addListener in interface ConfigService

getType

public java.lang.Class<ConfigService> getType()

Description copied from interface: AppContextService

Returns the type of service the class should be registered under.

Specified by:

getType in interface AppContextService<ConfigService>

Returns:

registration type