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oracle.jbo.common.ampool
Interface EnvInfoProvider

All Known Implementing Classes:

ELEnvInfoProvider, JUEnvInfoProvider, OCIEnvInfoProvider, RowIdAMEnvInfoProvider

public interface EnvInfoProvider

Invoked by DefaultConnectionStrategy when 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 information to Transaction.connect(String, Properties). Examples of dynamic information may include a database username or a database user password.

Application developers may also implement this interface to provide dynamic session information to ApplicationModuleImpl.prepareSession(oracle.jbo.Session). Examples of dynamic session environment may include the authenticated principal name.

Field Summary

static java.lang.String	INFO_TYPE_CONFIGURATION
static java.lang.String	INFO_TYPE_JDBC_PROPERTIES
static java.lang.String	INFO_TYPE_SESSION_ENVIRONMENT

Method Summary

java.lang.Object	getInfo(java.lang.String infoType, java.lang.Object env) Invoked by the ApplicationPool to acquire dynamic application context before the following ApplicationModule lifecycle events:
int	getNumOfRetries() Returns the number times that the default connection strategy should attempt to create/connect and application module instance before failing.
void	modifyInitialContext(java.lang.Object initialContext) Deprecated. getInfo(String, Object) should be implemented instead.

Field Detail

INFO_TYPE_SESSION_ENVIRONMENT

static final java.lang.String INFO_TYPE_SESSION_ENVIRONMENT

See Also:

Constant Field Values

INFO_TYPE_JDBC_PROPERTIES

static final java.lang.String INFO_TYPE_JDBC_PROPERTIES

See Also:

Constant Field Values

INFO_TYPE_CONFIGURATION

static final java.lang.String INFO_TYPE_CONFIGURATION

See Also:

Constant Field Values

Method Detail

getInfo

java.lang.Object getInfo(java.lang.String infoType,
                         java.lang.Object env)

Invoked by the ApplicationPool to acquire dynamic application context before the following ApplicationModule lifecycle events:

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 SessionCookie 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 ApplicationModuleImpl.prepareSession(oracle.jbo.Session).

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.

Parameters:

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: Transaction.connect(String, Properties) ApplicationModuleImpl.prepareSession(oracle.jbo.Session)

Returns:

Unused. Retained for legacy reasons.

See Also:

for an example implementation of an EnvInfoProvider for a JClient.

modifyInitialContext

void modifyInitialContext(java.lang.Object initialContext)

Deprecated. getInfo(String, Object) should be implemented instead.

Invoked when the application pool is creating a new application module instance. The environment hashtable may be modified by the EnvInfoProvider to provide dynamic application module context.

Since:

9.0.2

getNumOfRetries

int getNumOfRetries()

Returns the number times that the default connection strategy should attempt to create/connect and application module instance before failing.

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