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Custom Unwrappers
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
JDBC knows the java.sql.Wrapper API, which is implemented by all JDBC types in order to be able to "unwrap" a native driver implementation for any given type. For example:
// This may be some proxy from a connection pool
Connection c = getConnection();
// Sometimes, we want the native driver connection instance
OracleConnection oc = c.unwrap(OracleConnection.class);
Array array = oc.createARRAY("ARRAY_TYPE", new Object[] { "a", "b" });
jOOQ internally makes similar calls occasionally. For this, it needs to unwrap the native java.sql.Connection or java.sql.PreparedStatement instance. Unfortunately, not all third party libraries correctly implement the Wrapper API contract, so this unwrapping might not work. The org.jooq.Unwrapper SPI is designed to allow for custom implementations to be injected into jOOQ configurations:
// Your jOOQ configuration
Configuration c1 = getConfiguration();
Configuration c2 = c.derive(new Unwrapper() {
@Override
public <T> T unwrap(Wrapper wrapper, Class<T> iface) {
try {
if (wrapper instanceof Connection)
// ...
else if (wrapper instanceof Statement)
// ...
else
wrapper.unwrap(iface);
}
catch (SQLException e) {
// ...
}
}
});
// Work with the derived configuration, where needed
DSL.using(c2).fetch("...");
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