Logging in DBCP

Question

I\'m using Apache Commons DBCP. There is a task to track the inner behavior of the DBCP - number of active and idle connections.

I found out that DBCP lacks any such lo

Answer 1

I think aspects may be the solution to your quandry. Check out:

• http://static.springsource.org/spring/docs/current/spring-framework-reference/html/aop.html#aop-introduction-spring-defn
• http://www.ibm.com/developerworks/java/library/j-ajdt/
• http://www.eclipse.org/aspectj/doc/released/progguide/index.html

Basically, you can write an aspect or two that will "latch onto" the execution of some methods inside DBCP.

Something like:

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.ProceedingJoinPoint;

@Aspect
public class AroundExample {

  @Around("org.apache.commons.dbcp.PoolingDataSource.getConnection()")
  public Object doBasicPStuff(ProceedingJoinPoint pjp) throws Throwable {
    // write code to do what you want
    final PoolingDataSource ds = (PoolingDataSource) pjp.getThis();
    // log whatever you want

    // let it finish
    Object retVal = pjp.proceed();
    // stop stopwatch
    return retVal;
  }

}

That's just a tiny example. Aspects are really powerful and there's a bunch of different ways to do what you want. The code depends on whether you're using Spring or not, and what exactly you wanna log.

P.S. I haven't tested the above code.