APEX: Color-coded Maps, Lists, and Loops

Growing from a Salesforce Admin to a DevAdmin entailed getting familiar with APEX and doing exercises that simulated real-world business problems. To get a better grasp of APEX, I asked a friend to help me design a customized curriculum and come up with practice questions. On a side note, although there are many resources out there that teach you APEX the standard way (think CS101 in school), learning a new programming language and its gotchas with an experienced software engineer would tremendously help build your skills.

During our teaching sessions, my friend noticed that I had some difficulties in understanding two topics: JSON parsing (if you’ve done it in APEX, you know how convoluted it is) and anything that involved iterations over Maps and Lists. For the former, he provided a very easy method to dissect the JSON document into its corresponding APEX types

To help me with the latter, he showed me a cool way to visualize how the different variables and types are connected. This technique proved useful when I had to add/modify other people’s code.

Let’s start with defining a variable of type List which stores Accounts (this is the Salesforce Account Object).

List<Account> myList = new List<Account>();

Let’s iterate over the list to find the Account with the Name equal to “Visual”.

In the same context, a slightly more “advanced” example:

Now, let’s create the color map for the examples above:

2019-03-03_14-48-07

For the second example, let’s define a variable of type Map where the key is of type String and the value is of type String as well.

Map<String, String> myMap = new Map <String, String> ();

Let’s iterate over the map and find the key for which the value is equal to “Visual”:

2019-03-03_14-45-24.png

Now, let’s put together a color map for Maps:

2019-03-03_14-47-08

Finally, now that I have shown a color map for Lists and Maps, let’s create a color map for when you need to use both Maps and Lists.

2019-03-03_14-49-25

Over time, with more experience, it will become more natural to you, but if you’re just starting out with APEX development, I hope that this method will help to get a more solid understanding of how to iterate over maps and lists and will prevent you from doing silly bugs like I did  🙂

 

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