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[#8145] Add an UnwrapProvider SPI that allows for unwrapping underlying JDBC types through proprietary APIs

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lukaseder 2019-01-02 12:22:14 +01:00
parent ba5077d200
commit bc6bc1479c
1 changed files with 42 additions and 0 deletions
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42
jOOQ-manual/src/main/resources/org/jooq/web/manual-3.12.xml
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@ -3314,6 +3314,48 @@ configuration.set(
</html></content>
</section>
<section id="custom-unwrappers">
<title>Custom Unwrappers</title>
<content><html>
<p>
JDBC knows the <reference class="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:
</p>
</html><java><![CDATA[// 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" });]]></java><html>
<p>
jOOQ internally makes similar calls occasionally. For this, it needs to unwrap the native <reference class="java.sql.Connection"/> or <reference class="java.sql.PreparedStatement"/> instance. Unfortunately, not all third party libraries correctly implement the <code>Wrapper</code> API contract, so this unwrapping might not work. The <reference class="org.jooq.Unwrapper"/> SPI is designed to allow for custom implementations to be injected into jOOQ configurations:
</p>
</html><java><![CDATA[// 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("...");]]></java><html>
</html></content>
</section>
<section id="custom-settings">
<title>Custom Settings</title>
<content><html>