Book Image

Apex Design Patterns

By : Anshul Verma, Jitendra Zaa
Book Image

Apex Design Patterns

By: Anshul Verma, Jitendra Zaa

Overview of this book

Apex is an on-demand programming language providing a complete set of features for building business applications – including data models and objects to manage data. Apex being a proprietor programming language from Salesforce to be worked with multi tenant environment is a lot different than traditional OOPs languages like Java and C#. It acts as a workflow engine for managing collaboration of the data between users, a user interface model to handle forms and other interactions, and a SOAP API for programmatic access and integration. Apex Design Patterns gives you an insight to several problematic situations that can arise while developing on Force.com platform and the usage of Design patterns to solve them. Packed with real life examples, it gives you a walkthrough from learning design patterns that Apex can offer us, to implementing the appropriate ones in your own application. Furthermore, we learn about the creational patterns that deal with object creation mechanism and structural patterns that helps to identify the relationship between entities. Also, the behavioural and concurrency patterns are put forward explaining the communication between objects and multi-threaded programming paradigm respectively. We later on, deal with the issues regarding structuring of classes, instantiating or how to give a dynamic behaviour at a runtime, with the help of anti-patterns. We learn the basic OOPs principal in polymorphic and modular way to enhance its capability. Also, best practices of writing Apex code are explained to differentiate between the implementation of appropriate patterns. This book will also explain some unique patterns that could be applied to get around governor limits. By the end of this book, you will be a maestro in developing your applications on Force.com for Salesforce
Table of Contents (12 chapters)
Apex Design Patterns
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface

Functional decomposition


Usually, a developer starts building a trigger or page controller and ends up writing all the business logic within the trigger or controller itself. It is definitely easy and fast but hard to maintain.

Say, for example, we have to develop a Visualforce page with the custom functionality of generating an invoice. So, we begin our controller, as follows:

public class GenerateInvoiceController{ 
     
    public Invoice__c Invoice {get; set;} 
     
    //generate invoice 
    public void generateInvoice(){ 
         
        if(validate(Invoice )){ 
            insert Invoice ; 
        } 
        else{ 
            // handle validation errors 
        } 
    } 
     
    //validate invoice 
    public Boolean validate(Invoice__c Invoice){ 
        Boolean isValid = false; 
         
        // validation logic 
         
        return isValid; 
    } 
...