force.com – Page 5 – The Silver Lining

Meaningful Error Messages #24

July 14, 2009 by Wes

Having just managed to discover the cause of a particular error message, I thought I’d share the solution with the community.

Once in while you come across error messages that point you in absolutely no direction at all. Most recently I’ve been receiving ‘Failed validation: ApexPage‘. Thinking that I might get something more meaningful from the in-browser IDE I dumped my code there and got this little gem

	Error: common.request.servlet.PageDispatcher$Hack404
	Error: null

Considering that I was working with a several hundred line file, this made me less than happy. At times like these I whip out that old faithful tool of developer’s everywhere, the binary search algorithm.

Handling System.QueryException

July 9, 2009 by Wes

When attempting to fetch a single record from the database it is easy to run into the above exception. I’ve seen two schools of thought in dealing with this issue – mostly in the forums – and have been hoping to find a more official standpoint.

Unit Test Data Consistency

July 5, 2009 by Wes

I’m sure every Apex developer has had their Developer Org data interfere with their unit testing. Or perhaps you have coded unit tests that function perfectly within your Developer Org but when deployed to another Org fail because of a different, partial or empty database.

Of course as a developer this type on inconsistency within your work environment is extremely counter-productive. Initially I developed a methodology that did the job but wasn’t nearly as concise as I would have liked. More recently however I’ve developed a technical solution that is universal as well as quick to implement.

How to avoid Governor Limits [Part 1 of N]

July 1, 2009 by Wes

This topic is waaaay too big to cover in one post, so for now I’m going to concentrate on avoiding this particular exception: ‘Too many SOQL queries’. I will also touch on the ‘Too many DML rows’ exception, and expand on it’s solutions in another post. Bulkifying your triggers is another topic I will cover at some later date, but the methodologies mentioned here should go some way towards helping you avoid some of the Governor Limits there too.

SOQL ‘Distinct’ Keyword

June 7, 2024June 28, 2009 by Wes

It doesn’t exist. Sad but true.

In SQL there is a clause that ensures a duplicate free result set is returned by any query you issue e.g. You want to retrieve a duplicate free list of first names from the table clients. The column holds the following values: Alice, Bob, Alice. In Oracle SQL you would use the following query (and it would return the names Alice and Bob each listed once).

SELECT DISTINCT firstname
FROM clients;

Unfortunately SOQL doesn’t have this capability although there is an Apex trick that can be employed as a work-around.

Force.com Anonymous Blocks

June 27, 2009 by Wes

Anonymous Blocks. Where have you been all my life? Right under my nose apparently. I am embarrassed to say I’ve only discovered this little jewel of the Force.com platform recently, and although I’ve managed without it, I’m pretty sure that it’ll be a regular feature in my development experience.

What are they you ask? It’s simply the ability to execute a bit of Apex code on the fly. This is awesome^6 at least. Often during the development process you need to clean your data. Either you’ve changed your logic and that data is affecting functionality, or perhaps you need to remove data en masse. This is simple with Anonymous Blocks, just write up a short script that will restore your data to an ‘initial’ state and save it for future use.

Force.com & Case-Sensitivity

June 22, 2009 by Wes

pnf2ycurh4The Force.com platform is case-insensitive. Mostly. It’s difficult to find information on which areas are case-sensitive so I’ve compiled this list of what I’ve discovered thus far(I’ll add notable cases as I encounter them).

VisualForce Component Ids & Javascript

June 17, 2009 by Wes

I have retired this approach in favour of a much neater solution that can be found here.

Salesforce used in conjunction with JavaScript and Ajax can be pretty smashing. I’ve used a number of JavaScript libraries that make you want to high-five yourself when implemented. There can(and probably will) be some frustration while you bend a library and make it fit within the Salesforce framework, although Ron Hess has some pretty sweet examples for you to pore over.

One simple frustration I’ve come across is that of retrieving elements by Id. Salesforce has an intelligent scheme in place which ensures that HTML elements don’t have duplicate Ids and therefore conform to W3C standards.

Datatable VS Repeat

June 16, 2009 by Wes

A long long time ago, in an office not far away I pondered the need for so much variety in the VisualForce ‘structural’ component library. I mean, dataTables, pageBlockTables, outputPanels, panelGrids, repeats, panelBars.. jeez Louise. And when would I use them all? How should I combine them? If I type google in google will I break the Internet? Okay, I didn’t really ponder the last one, everyone knows that’s true.

Nowadays I’d like to think I have a feel for what to use, and when. More specifically I’m going to dig into when to use dataTables over repeats, and vice versa(The only real difference I can find between pageBlockTable and dataTable is that dataTable has a cool onhover JS handler that highlights the currently onhovered row, so I’m totally going to ignore pageBlockTable. Speak to the hand pageBlockTable, because the face ain’t listening).