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package org.jooq;

import java.sql.Connection;
import java.sql.Wrapper;

An unwrapper SPI that can be used to override the default unwrapping
algorithm.

In some cases, jOOQ needs to get access to the native JDBC driver APIs in
order to call vendor specific methods, such as Oracle's
OracleConnection.createARRAY(). jOOQ doesn't expect clients to provide a native JDBC Connection through the ConnectionProvider SPI. Implementations may well provide jOOQ with some proxy that implements things like logging, thread-bound transactionality, connection pooling, etc. 
 In order to access the native API, Wrapper.unwrap(Class<Object>) needs to be called, or in some cases, when third party libraries do not properly implement this contract, some specific methods are called reflectively, including: 


org.springframework.jdbc.datasource.ConnectionProxy#getTargetConnection()
org.apache.commons.dbcp.DelegatingConnection#getDelegate()
org.jboss.jca.adapters.jdbc.WrappedConnection#getUnderlyingConnection()
...


Not all such third party libraries are "known" to jOOQ, so clients can
implement their own unwrapper to support theirs.
Author:
Lukas Eder/**
 * An unwrapper SPI that can be used to override the default unwrapping
 * algorithm.
 * <p>
 * In some cases, jOOQ needs to get access to the native JDBC driver APIs in
 * order to call vendor specific methods, such as Oracle's
 * <code>OracleConnection.createARRAY()</code>. jOOQ doesn't expect clients to
 * provide a native JDBC {@link Connection} through the
 * {@link ConnectionProvider} SPI. Implementations may well provide jOOQ with
 * some proxy that implements things like logging, thread-bound
 * transactionality, connection pooling, etc.
 * <p>
 * In order to access the native API, {@link Wrapper#unwrap(Class)} needs to be
 * called, or in some cases, when third party libraries do not properly
 * implement this contract, some specific methods are called reflectively,
 * including:
 * <p>
 * <ul>
 * <li><code>org.springframework.jdbc.datasource.ConnectionProxy#getTargetConnection()</code></li>
 * <li><code>org.apache.commons.dbcp.DelegatingConnection#getDelegate()</code></li>
 * <li><code>org.jboss.jca.adapters.jdbc.WrappedConnection#getUnderlyingConnection()</code></li>
 * <li>...</li>
 * </ul>
 * <p>
 * Not all such third party libraries are "known" to jOOQ, so clients can
 * implement their own unwrapper to support theirs.
 *
 * @author Lukas Eder
 */
public interface Unwrapper {

    
Unwrap a wrapped type from a JDBC Wrapper. /**
     * Unwrap a wrapped type from a JDBC {@link Wrapper}.
     */
    <T> T unwrap(Wrapper wrapper, Class<T> iface);
}