Re: OT: easiest way to create a custom PreparedStatement

We use java.lang.reflect.Proxy in our production systems to do things like log SQL statements, do a little bookkeeping for application-level replication, log timings and the like.  Works great.

Here's a snippet that we use to wrap a PreparedStatement with a proxy to do some logging every time somebody calls any method on it.

-- Mark Lewis


         final PreparedStatement realStatement = xxx;

        PreparedStatement debugWrapped = (PreparedStatement)Proxy.newProxyInstance(getClass().getClassLoader(), new Class[]{PreparedStatement.class}, new InvocationHandler() {
            public Object invoke(Object instance, Method method, Object [] params) throws Throwable {
            StringBuffer buf = new StringBuffer();
            buf.append("Called ").append(method.getName());
            buf.append('(');
            if(params != null) {
            for(int i=0; i<params.length; i++) {
            if(i > 0) buf.append(',');
            buf.append(String.valueOf(params[i]));
            }
            }
            buf.append(')');
            log.debug(buf);
            try {
            return method.invoke(realStatement, params);
            }
            catch(InvocationTargetException ex) {
            throw ex.getCause();
            }
            }
            });




On Tue, 2005-06-28 at 14:55 -0500, Craig Servin wrote:

Or you could use:

java.lang.reflect.Proxy


On Tuesday 28 June 2005 01:55 pm, Kevin Murphy wrote:
> I am modifying some existing data loading code (that only makes use of 4
> or 5 methods from PreparedStatement) to optionally be able to *not*
> connect to a database but instead dump either the generated SQL code or
> the raw insert data to files on the file system.
>
> It would be great if I could just overload PreparedStatement with my own
> classes, but unfortunately it is an interface, so I presumably need to
> implement stubs for the umpty-ump methods defined by PreparedStatement?
>
> Is this true, and if so, what is the easiest/fastest way to do this (if
> it is even possible)?
>
> I am a java newbie, by the way.  Don't flame me too hard.  I did say
> "OT", after all ;-)
>
> Thanks,
> Kevin
>
>
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