An SBB can use JDBC to execute SQL statements.
It must declare this intent in an extension deployment descriptor: the oc-sbb-jar.xml file (contained in the SBB jar file in the META-INF directory).
The <resource-ref> element (which must be inside the <sbb> element of oc-sbb-jar.xml) defines the JDBC datasource it will use.
Sample <resource-ref>
Below is a sample <resource-ref> element defining a JDBC datasource:
<resource-ref>
<!-- Name under the SBB's java:comp/env tree where this datasource will be bound -->
<res-ref-name>foo/datasource</res-ref-name>
<!-- Resource type - must be javax.sql.DataSource -->
<res-type>javax.sql.DataSource</res-type>
<!-- Only Container auth supported -->
<res-auth>Container</res-auth>
<!-- Only Shareable scope supported -->
<res-sharing-scope>Shareable</res-sharing-scope>
<!-- JNDI name of target JDBC resource, relative to Rhino's java:resource tree. -->
<res-jndi-name>jdbc/myresource</res-jndi-name>
</resource-ref>
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In the above example, the <res-jndi-name> element has the value jdbc/myresource, which maps to the
JDBC resource created in the example.
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How an SBB obtains a JDBC connection
An SBB can get a reference to an object that implements the datasource interface using a JNDI lookup. Using that object, the SBB can then obtain a connection to the database. The SBB uses that connection to execute SQL queries and updates.
For example:
import javax.naming.*;
import javax.slee.*;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
...
public abstract class SimpleSbb implements Sbb {
public void setSbbContext(SbbContext context) {
try {
Context myEnv = (Context)new InitialContext().lookup("java:comp/env");
ds = (DataSource)myEnv.lookup("foo/datasource");
}
catch (NamingException e) {
// JNDI lookup failed
}
}
public void onSimpleEvent(SimpleEvent event, ActivityContextInterface context) {
Connection conn;
try {
conn = ds.getConnection();
}
catch (SQLException e) {
// could not get database connection
}
...
}
...
private DataSource ds;
...
}SQL programming
When an SBB executes in a transaction and invokes SQL statements, the SLEE controls transaction management of the JDBC connection.
This lets the SLEE perform last-resource-commit optimisation.
Invoking JDBC methods which affect transaction management have no effect or undefined semantics when called from an application component isolated by a SLEE transaction.
The methods (including any overridden form) that affect transaction management on the java.sql.Connection interface are listed below.
These methods should not be invoked by SLEE components:
-
close -
commit -
rollback -
setAutoCommit -
setIsolationLevel -
setSavePoint -
releaseSavePoint
