Skip to main content

ACCU Conference 2009 Proposal (3)

By
Title: Boiler Plating Database Resource Cleanup

Type: Case study

Duration: 45 min

Speaker: Paul Grenyer

Speaker biography: Paul has been programming in one form or another for over 20 years. After several years using C++ and a brief period using C#, Paul has now ended up somewhere he hoped he'd never be, programming in Java, and finding he really quite likes it. After time in industries such as marking machinery, direct mail, mobile phones, investment banking and Internet TV, Paul is currently working for an exciting new insurance industry based startup in Norwich. He has been an ACCU member since 2001, a regular publications contributor (including the new Desert Island Books column), creator of the mentored developers and a committee member for most of that time. When he's not programming or getting used to married life and being a step parent, Paul thoroughly enjoys science fiction, heavy metal and cycling.


I've been using Java for nearly twelve months now and I am finding that I like it. There are only two things that I have discovered so far that make make me wonder what the creators of Java were thinking: exception handling and layout managers. I'll cover layout managers in a later article.

Java is a garbage collected language. If garbage collection is meant to help you clean up memory, why hasn't something been developed to help objects release resources? Java has finalizers, but as Joshua Bloch points out in Effective Java finalizers cannot be relied upon. Proper cleanup of resources is left to the developer whose only real friend is finally.

In languages like C# the IDisposable interface can be used to aid cleanup. The IDisposable interface has a single method called Dispose. All of an object's cleanup code should be placed in this method and calling the method manually or via using ensures resources are released. The draw back is that even IDisposable requires the client code to to use it. There is nothing like this available in Java, but I have an even better solution which takes away the dependence on a classes user to do any cleaup.

In this presentation I'll look briefly at the vast amount of exception handling code that must be written to cleanly close result set, statement and connection objects when accessing a database and then more in depth at one possible method of boiler plating it.

Comments

Post a Comment

Popular posts from this blog

Write Your Own Load Balancer: A worked Example

By
I was out walking with a techie friend of mine I’d not seen for a while and he asked me if I’d written anything recently. I hadn’t, other than an article on data sharing a few months before and I realised I was missing it. Well, not the writing itself, but the end result. In the last few weeks, another friend of mine, John Cricket , has been setting weekly code challenges via linkedin and his new website, https://codingchallenges.fyi/ . They were all quite interesting, but one in particular on writing load balancers appealed, so I thought I’d kill two birds with one stone and write up a worked example. You’ll find my worked example below. The challenge itself is italics and voice is that of John Crickets. The Coding Challenge https://codingchallenges.fyi/challenges/challenge-load-balancer/ Write Your Own Load Balancer This challenge is to build your own application layer load balancer. A load balancer sits in front of a group of servers and routes client requests across all of the serv...
Post a Comment
Read more

Catalina-Ant for Tomcat 7

By
I recently upgraded from Tomcat 6 to Tomcat 7 and all of my Ant deployment scripts stopped working. I eventually worked out why and made the necessary changes, but there doesn’t seem to be a complete description of how to use Catalina-Ant for Tomcat 7 on the web so I thought I'd write one. To start with, make sure Tomcat manager is configured for use by Catalina-Ant. Make sure that manager-script is included in the roles for one of the users in TOMCAT_HOME/conf/tomcat-users.xml . For example: <tomcat-users> <user name="admin" password="s3cr£t" roles="manager-gui, manager-script "/> </tomcat-users> Catalina-Ant for Tomcat 6 was encapsulated within a single JAR file. Catalina-Ant for Tomcat 7 requires four JAR files. One from TOMCAT_HOME/bin : tomcat-juli.jar and three from TOMCAT_HOME/lib: catalina-ant.jar tomcat-coyote.jar tomcat-util.jar There are at least three ways of making the JARs available to Ant: Copy the JARs into th...
22 comments
Read more

RESTful Behaviour Guide

By
I’ve used a lot of existing Representational State Transfer (REST) APIs and have created several of my own. I see a lot of inconsistency, not just between REST APIs but often within a single REST API. I think most developers understand, at a high level, what a REST API is for and how it should work, but lack a detailed understanding. I think the first thing they forget to consider is that REST APIs allow you to identify and manipulate resources on the web. Here I want to look briefly at what a REST API is and offer some advice on how to structure one, how it should behave and what should be considered when building it. I know this isn’t emacs vs vi, but it can be quite contentious. So, as  Barbossa from Pirates of the Caribbean said, this “...is more what you’d call ‘guidelines’ than actual rules.” Resources & Identifiers In their book, Rest in Practice - Hypermedia and Systems Architecture (‎ISBN: 978-0596805821), Jim Webber, Savas Parastatidis and Ian Robinson describe resour...
1 comment
Read more