💃 Design Patterns for Salesforce🕺

Good morning, Salesforce Nerds! It’s that time again. ⌚️ I’ve said it before - the ChaCha loves a good pattern!

Often times, the simplest solutions can provide the greatest benefits.

Today’s design pattern fits squarely within this mantra. 🧘 

Let’s check out a fundamental pattern Salesforce devs can use to mitigate those pesky governor limits!

Read on for our take on the Singleton Pattern. 👇️ 

TABLE OF CONTENTS

Design Patterns for Salesforce

• Design Patterns

• Singleton Pattern

• Simple Problem

• The Solution

• Takeaway

Quick Recap

Design Patterns

We’ve written a bit about these before.

From a high-level, design patterns are solutions to problems developer’s often face. They’re blueprints we can follow. 🏗️ 

These should be treated as guiding principles for Salesforce devs. 💯 

They'll aid in the structure and organization of your codebase and help set you on a path to:

✅ Efficiency

✅ Maintainability

✅ Scalability

So, let’s dig into one of my fav’s! 🤩 

Singling one out

Singleton Pattern

Officially, The Gang of Four(GoF) came up with this definition:

Let’s break that down a bit. 😅 It’s actually a very straightforward implementation that might have you wondering where the benefits are.

👉️ This is a Creational Pattern.

👉️ Provides a single, global point of access to a class instance throughout the codebase.

👉️ Ensures only one instance of this class is created.

👉️ Minimizes memory usage by reducing object instantiation & query execution. Boosting performance & mitigating governor limits.

👉️ Lazy-loaded instantiation improves performance.

Let’s see an example

Simple Problem

There are tons of use cases for a Singleton.

✅ Maybe there’s a SOQL query you need to run often throughout a transaction. For example, if you’re using SObject’s for configuration or metadata-like data.

✅ Maybe you’re regularly access Custom Metadata Type records for calculations.

✅ Maybe you’re accessing & using data from Platform Cache

All of these (and way more) are legit …

Right now, I’m going to show another use case I regularly rely on the Singleton Pattern for. 🥁 

Invoking a call to Schema.getGlobalDescribe(); 🫢 

Map<string, Schema.SObjectType> describeResult = Schema.getGlobalDescribe();

If you’re a Salesforce dev you’re probably already dreading the performance impact on this one.

Especially if it’s invoked multiple times in a single transaction. 🤦 

Or what about if the invocation is placed inside of a loop! ⛔️ 

These types of hidden defects in a codebase can become major issues when the org needs to scale.

Just a little bit of Singleton code will help enormously here.

Show me the code!

The Solution

Here’s how I’ve implemented this Singleton before:

Step 1 - Create a public class. I always like to name my things clearly so I’ve gone with GlobalDescribeSingleton 

Step 2 - Declare a private static variable of type GlobalDescribeSingleton

Step 3 - Declare a public get/private set variable of type Map<string, Schema.SObjectType>

Step 4 - Create a private constructor and populate your Map variable from Step 3

Step 5 - Create a public static method returning your class type that checks if your variable from Step 2 has already been initialized before returning it.

public class GlobalDescribeSingleton {
    private static GlobalDescribeSingleton instance = null;
    public Map<string, Schema.SObjectType> describeResult { get; private set; }
    
    private GlobalDescribeSingleton() {
        describeResult = Schema.getGlobalDescribe();
    }

    public static GlobalDescribeSingleton getInstance() {
        if(instance == null) { instance = new GlobalDescribeSingleton(); }
        return instance;
    }
}

Wrapping it up

Takeaway

That’s really it. There’s not any more to it that that. 🤷 

When a client calls this code it guarantees only a single instance of the class exists and that the getGlobalDescribe() is invoked only once! 💥 

Speaking of a client. Now you can call this code in your application and you automatically pick up all the benefits! 👇️ 

GlobalDescribeSingleton.getInstance()

SOUL FOOD

Today’s Principle

and now....Salesforce Memes