com.mchange.v2.c3p0.C3P0ProxyConnection Maven / Gradle / Ivy
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package com.mchange.v2.c3p0;
import java.sql.Connection;
import java.sql.SQLException;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
/**
* Most clients need never use or know about this interface -- c3p0-provided Connections
* can be treated like any other Connection.
*
* An interface implemented by proxy Connections returned
* by c3p0 PooledDataSources. It provides protected access to the underlying
* dbms-vendor specific Connection, which may be useful if you want to
* access non-standard API offered by your jdbc driver.
*/
public interface C3P0ProxyConnection extends Connection
{
/**
* A token representing an unwrapped, unproxied jdbc Connection
* for use in {@link #rawConnectionOperation}
*/
public final static Object RAW_CONNECTION = new Object();
/**
*
Allows one to work with the unproxied, raw Connection. Some
* database companies never got over the "common interfaces mean
* no more vendor lock-in!" thing, and offer non-standard API
* on their Connections. This method permits you to "pierce" the
* connection-pooling layer to call non-standard methods on the
* original Connection, or to pass the original Connections to
* functions that are not implementation neutral.
*
* To use this functionality, you'll need to cast a Connection
* retrieved from a c3p0 PooledDataSource to a
* C3P0ProxyConnection.
*
* This method works by making a reflective call of method m on
* Object target (which may be null for static methods), passing
* and argument list args. For the method target, or for any argument,
* you may substitute the special token C3P0ProxyConnection.RAW_CONNECTION
*
* Any Statements or ResultSets returned by the operation will be proxied
* and c3p0-managed, meaning that these resources will be automatically closed
* if the user does not close them first when this Connection is checked back
* into the pool. Any other resources returned by the operation are the user's
* responsibility to clean up!
*
* Incautious use of this method can corrupt the Connection pool, by breaking the invariant
* that all checked-in Connections should be equivalent. If your vendor supplies API
* that allows you to modify the state or configuration of a Connection in some nonstandard way,
* you might use this method to do so, and then check the Connection back into the pool.
* When you fetch another Connection from the PooledDataSource, it will be undefined
* whether the Connection returned will have your altered configuration, or the default
* configuration of a "fresh" Connection. Thus, it is inadvisable to use this method to call
* nonstandard mutators.
*/
public Object rawConnectionOperation(Method m, Object target, Object[] args)
throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException;
}