public interface EnvInfoProvider
DefaultConnectionStrategywhen the application pool is establishing connection to the database or when the application pool is recycling an ApplicationModule.
Application developers may implement this interface to provide dynamic
Examples of dynamic information may include a database username or a database
Application developers may also implement this interface to provide dynamic
session information to
Examples of dynamic session environment may include the authenticated
|Modifier and Type||Field and Description|
|Modifier and Type||Method and Description|
Invoked by the ApplicationPool to acquire dynamic application context before the following ApplicationModule lifecycle events:
Returns the number times that the default connection strategy should attempt to create/connect and application module instance before failing.
static final java.lang.String INFO_TYPE_SESSION_ENVIRONMENT
static final java.lang.String INFO_TYPE_JDBC_PROPERTIES
static final java.lang.String INFO_TYPE_CONFIGURATION
java.lang.Object getInfo(java.lang.String infoType, java.lang.Object env)
1. A Configuration is loaded
2. An ApplicationModule instance is created
3. An ApplicationModule instance is connected
4. An ApplicationModule instance is reused by an ApplicationPool
session which is differnt than the session which had previously
used it. Please see
for more information about ApplicationPool sessions.
An EnvInfoProvider implementation may respond to the request by modifying the passed environment. This gives the EnvInfoProvider implementation an opportunity to dynamically define Configuration properties, ApplicationModule envirionment properties, or JDBC properties.
getInfo is always invoked with a Hashtable instance though
it may also be invoked with a java.util.Properties (extends
Hashtable) in some scenarios. Any session context that is specified
by getInfo will also be available in the BC4J middle tier via
Session and during invocation of
getInfo may also be used to dynamically specify JDBC credentials. For example, the following code snippet may be used to dynamically specify the JDBC credentials for the current ApplicationModule session (please see the article at http://otn.oracle.com/products/jdev/howtos/bc4j/howto_dynamic_jdbc.html for more information about dynamically specifying JDBC credentials to BC4J): ((Hashtable)env).put(Configuration.DB_USERNAME_PROPERTY, <username>); ((Hashtable)env).put(Configuration.DB_PASSWORD_PROPERTY, <password>); ((Hashtable)env).put(Configuration.DB_CONNECT_STRING_PROPERTY, <connect string>); return null;
Finally, getInfo may also be invoked multiple times during a connect attempt, if previous connect attempts have failed. This is intended to give the EnvInfoProvider an opportunity to correct the dynamic JDBC credentials before ultimately failing with an exception. The connection exception, if one occurred, is available to the EnvInfoProvider via the context with the DefaultConnectionStrategy.LAST_EXCEPTION key.
infoType- Indicates the type of info that is being requested. Please note that before connecting the pooling framework may invoke getInfo multiple times with the following values for the info parameter: 1. INFO_TYPE_SESSION_ENVIRONMENT 2. INFO_TYPE_JDBC_PROPERTIES 3. INFO_TYPE_CONFIGURATION 4. Configuration.DB_USERNAME_PROPERTY 5. Configuration.DB_PASSWORD_PROPERTY The last two are not realy info types (they are JDBC properties) but are maintained for legacy reasons.
env- a Hashtable object containing the environment that will be passed to:
for an example implementation of an EnvInfoProvider for a JClient.
void modifyInitialContext(java.lang.Object initialContext)
getInfo(String, Object)should be implemented instead.