DML currently not allowed

This almost belongs in my sarcastically titled, “Meaningful Error Messages ..” series, but as it has traceable causes, I thought I’d write something up on it’s most frequent causes (I meant to write this up a few months ago, but it slipped my mind (find it in your heart to forgive an ol’ developer) and now I think it’s time the world knew).

‘DML currently not allowed’, what could that mean? Well it means that DML isn’t allowed. And that it’s not allowed right now, but with the slight promise that given time, it will be allowed. Often in the past, hoping against hope, I kept on pressing that button/link/onclick-area, but the cloud never changed it’s mind. With a sigh I constructed the google-search query and began trundling through the results.

Flickr + jQuery + Force.com = Awesome^5 [Part 2]

Okay software developing enthusiasts, I’m back from Paris (you didn’t know I was gone did ya?), I’m a year older and culturally, I’m richer (well I’d like to think so at least). It’s time to complete our two-part series on integrating disparate systems using  the most-excellent combination of web services, jQuery and the Force.com platform. In part 1 we learnt how to connect to a third-party endpoint (Flickr in our case), and consume their SOAP-based web services. Now we’re going to jazz it all up with our spiffy jQuery gallery carousel. Let’s have another look at where we want to be at the end of this all,

Flickr + jQuery + Force.com = Awesome^5 [Part 1]

Being a mathematician, equations like those in the title usually make me wanna poke someone in the eye.. but in this case it’s just too true to not use. My aim over the next two posts is to provide you with the knowledge to,

1. Consume web services from within the Force.com platform(without WSDLs).
2. Use web services(we’ll be using the SOAP-based variety), or other agents, as data sources for integration with JavaScript, and in particular, jQuery.

I will cover point 1 in this post, and then bring it all together in a second post which will cover point 2. It’s gonna be a rocky ride, but I’m sure all you cowboys/girls/others can handle it. Just so we know where we want to end up, our final product will look something like this,

Multiple forms in a single VisualForce page

I thought I’d post a quick tip I picked up from Jill Wetzler, Visualforce(and, I suspect JavaScript) Legend. When developing pages that contain more than a single area that could be submitted(not necessarily refreshed) I would usually wrap these areas with forms. Jill pointed out that I’d been a silly bloke(my words, not hers) and could use a single form and wrap each area with an<apex:actionregion> tag.

SOSL, friend or foe?

As requested by Chris Peterson I’d like to dig a bit more into SOSL. This is as much a lesson for me as anyone else, and I’d be ecstatic if anyone out there could offer a bit more depth on the topic. SOSL (or sossel) is Salesforce’s search language, and in my experiences definitely has it’s advantages(which are significant in the CRM) and limitations(which may stem from me/us just not knowing how to use it properly). First let’s make sure you have the standard docs memorised.

Basic doc on SOSL within Apex code

API doc, thorough on syntax although might not have some common examples.

Doc for dynamic SOSL

Right, now that we have those committed to memory we can delve into what I think are the advantages and disadvantages of SOSL..

OOP in the Cloud – ReCaptcha Revisited

Can I get a OOP OOP?! That’s right folks, OOP is alive and well on the Force.com platform, and over the past few months I’ve had some pretty thrilling experiences implementing projects using those trusted sidekicks Encapsulation, Polymorphism and trusty ol’ Abstraction. There is some pretty sweet documentation on the subject, but I thought I’d demo something supercool I learnt by combining two articles from the Force.com wiki.

Passing Apex values to Javascript Code.

For the sake of completeness, and because I’ve received a large number of hits from the googled phrase ‘pass apex to javascript’, I thought it would be appropriate for me to write an article detailing the converse of an operation explain in a previous post.

Passing Javascript values to Apex code.

It’s been a while crocodile. Truth be told I was working furiously on my Site’s Developer Challenge entry, and then I was just too pooped to post. I’m sure you were all waiting with bated breath for my next post.. nooooot.

Anyway, let’s get down to brass tacks. Quite often I’ve needed to manipulate variable values in-page(Visualforce) with JS, and then pass these modified values to Apex or a Standard Controller. Just as often I’ve simply dismissed the possibility and worked-around the issue. Recently I was speaking to a fellow who proposed the beginnings of a terribly smashing idea and thought I’d try my hand at a simple implementation.

Lists of SObjects and Classes – By value or reference?

I found a quirky bug in my code some time back, and realised that the cause of the bug was quite a useful Apex feature viz. SObjects and Apex classes are passed by reference and not value.

What does this mean you say? Let’s start by defining what passing by value means.

In a nutshell, if you pass a variable to a method and it’s a Force.com primitive type(Integer, String etc.) it will be passed by value meaning that the value of the variable and not the variable itself is passed to the method

Dynamic Custom Labels – Part 2

Quite recently I came across an interesting forum post by XactiumBen that mentioned some awesomesauce abilities of params in outputTexts. I’ve written an article detailing the basics of this functionality before, and thought I’d document these advanced capabilities too. For anyone interested you can read Part 1 here.

Now I’m sure some of you thought that simply being able to use dynamic custom labels was pretty smashing in it’s own right, but you ain’t seen nothing yet. Imagine a world where you could not only use dynamic custom labels, but were also able to use decision structures in those labels. That’s the world we live in buddy!