com.boylesoftware.cb2.commons.property
Class PropertySharedBLO

java.lang.Object
  com.boylesoftware.cb2.BLObject
      com.boylesoftware.cb2.commons.property.PropertySharedBLO

All Implemented Interfaces:

java.io.Serializable

public class PropertySharedBLO

extends BLObject

Generic BLO for managing database-stored application properties, that are used by the application context via com.boylesoftware.cb2.appProperties.query property. This BLO can be deployed as a shared BLO since does not contain any session specific data. The BLO needs a number of initialization parameters that name the database table, which contains additional application properties, the column in the table, which contains property names, and the column, which contains property values. Here is how the BLO can be deployed in the blo-config.xml file:

 <blo name="property" shared="true">
   <init-param>
     <param-name>table</param-name>
     <param-value>Property</param-value>
   </init-param>
   <init-param>
     <param-name>nameColumn</param-name>
     <param-value>name</param-value>
   </init-param>
   <init-param>
     <param-name>valueColumn</param-name>
     <param-value>value</param-value>
   </init-param>
 </blo>

Note, that if the application does not use database-stored application properties, that is com.boylesoftware.cb2.appProperties.query is not set, the init method of this BLO throws an exception.

Version:

$Id: PropertySharedBLO.java,v 1.3 2004/04/29 19:32:47 levahim Exp $

Author:

Lev Himmelfarb

See Also:

Serialized Form

Field Summary

protected java.lang.String	dataSourceName Name of the data source corresponding to the database where the properties are stored.
protected java.lang.String	nameColumn Name of the column, which contains application property names.
protected static BTreeMap	NONCHANGABLE_PROPS Set of name prefixes for application properties that cannot be stored in the database and can be specified only in the cb2app.properties file.
static int	PROPTYPE_BASIC Property type, returned by getPropertyType method, which indicates that the property comes from the cb2app.properties file.
static int	PROPTYPE_DB Property type, returned by getPropertyType method, which indicates that the property comes from the database.
static int	PROPTYPE_IMMUTABLE Property type, returned by getPropertyType method, which indicates that the property comes from the cb2app.properties file and its value cannot be changed, because it is used by the application context before it processes additional properties from the database.
static int	PROPTYPE_OVERRIDDEN Property type, returned by getPropertyType method, which indicates that the property comes from the cb2app.properties file, but its value has been overridden by a property with the same name stored in the database.
static int	PROPTYPE_UNKNOWN This value is returned by getPropertyType method when type of a non existant property is requested.
protected java.lang.String	table Name of the database table, which contains application properties.
protected java.lang.String	valueColumn Name of the column, which contains application property values.

Fields inherited from class com.boylesoftware.cb2.BLObject

bloc, log

Constructor Summary

PropertySharedBLO()

Method Summary

java.util.SortedMap	getProperties() Gets all application properties as a sorted map.
int	getPropertyType(java.lang.String name) Tells the specified application property's type, which is where its value comes from.
protected void	init() Initializes the BLO.
void	resetProperty(java.lang.String name) Resets an application property's value.
void	saveProperties(java.util.Properties newProps) Saves properties from the specified set of properties that have different from current application properties values to the database.

Methods inherited from class com.boylesoftware.cb2.BLObject

activate, destroy, getApplicationContext, getBLO, getBLOContainer, getDAO, getDAO, getDAOConfig, getDAOConfig, getDeploymentName, getInitParameter, getLastErrors, isRollbackOnly, setErrors, setRollbackOnly

Methods inherited from class java.lang.Object

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

Field Detail

PROPTYPE_UNKNOWN

public static final int PROPTYPE_UNKNOWN

This value is returned by getPropertyType method when type of a non existant property is requested.

See Also:

Constant Field Values

PROPTYPE_IMMUTABLE

public static final int PROPTYPE_IMMUTABLE

Property type, returned by getPropertyType method, which indicates that the property comes from the cb2app.properties file and its value cannot be changed, because it is used by the application context before it processes additional properties from the database.

See Also:

Constant Field Values

PROPTYPE_BASIC

public static final int PROPTYPE_BASIC

Property type, returned by getPropertyType method, which indicates that the property comes from the cb2app.properties file.

See Also:

Constant Field Values

PROPTYPE_OVERRIDDEN

public static final int PROPTYPE_OVERRIDDEN

Property type, returned by getPropertyType method, which indicates that the property comes from the cb2app.properties file, but its value has been overridden by a property with the same name stored in the database.

See Also:

Constant Field Values

PROPTYPE_DB

public static final int PROPTYPE_DB

Property type, returned by getPropertyType method, which indicates that the property comes from the database.

See Also:

Constant Field Values

NONCHANGABLE_PROPS

protected static final BTreeMap NONCHANGABLE_PROPS

Set of name prefixes for application properties that cannot be stored in the database and can be specified only in the cb2app.properties file.

dataSourceName

protected java.lang.String dataSourceName

Name of the data source corresponding to the database where the properties are stored. Set in the init method from com.boylesoftware.cb2.appProperties.dataSource application property. If the property is not defined, set to "default".

table

protected java.lang.String table

Name of the database table, which contains application properties. Set in the init method from the "table" BLO initialization parameter.

nameColumn

protected java.lang.String nameColumn

Name of the column, which contains application property names. Set in the init method from the "nameColumn" BLO initialization parameter.

valueColumn

protected java.lang.String valueColumn

Name of the column, which contains application property values. Set in the init method from the "valueColumn" BLO initialization parameter.

Constructor Detail

PropertySharedBLO

public PropertySharedBLO()

Method Detail

init

protected void init()
             throws BLException

Initializes the BLO.

Overrides:

init in class BLObject

Throws:

BLException - if the BLO cannot be initialized.

getPropertyType

public int getPropertyType(java.lang.String name)

Tells the specified application property's type, which is where its value comes from.

Parameters:

name - the application property's name.

Returns:

one of PROPTYPE_xxx values.

getProperties

public java.util.SortedMap getProperties()

Gets all application properties as a sorted map.

Returns:

map with all application properties sorted by their names.

saveProperties

public void saveProperties(java.util.Properties newProps)
                    throws BLException

Saves properties from the specified set of properties that have different from current application properties values to the database. It also saves properties that are not currently defined at all. This method can insert new values into the database, and it can update existing values. When all database operations have been finished successfully, the method calls setProperty on the applicatrion context for all changed properties.

Parameters:

newProps - collection of application property values.

Throws:

BLException - if a database error happens, or in case of an attempt to change an immutable property.

resetProperty

public void resetProperty(java.lang.String name)
                   throws BLException

Resets an application property's value. This method deletes the value from the database, which in the case of a database property removes it from the set of application properties, and in the case of an overridden basic property resets its value to the original one as defined in the cb2app.properties file. This method has no effect if the property is not stored in the database and it calls setProperty on the application context if any change has been made.

Parameters:

name - the application property's name.

Throws:

BLException - if a database error happens.