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- Herausgeber: Packt Publishing
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Harness the power of Apex design patterns to build robust and scalable code architectures on the Force.com platform
About This Book
- Apply Creational, Structural and behavioural patterns in Apex to fix governor limit issues.
- Have a grasp of the anti patterns to be taken care in Apex which could have adverse effect on the application.
- The authors, Jitendra Zaa is a salesforce MVP and Anshul Verma has 12+ years of experience in the area of application development.
Who This Book Is For
If you are a competent developer with working knowledge of Apex, and now want to deep dive into the world of Apex design patterns to optimize the application performance, then this book is for you. Prior knowledge of Salesforce and Force.com platform is recommended.
What You Will Learn
- Apply OOPs principal in Apex to design a robust and efficient solution to address various facets to a business problem
- Get to grips with the benefits and applicability of using different design patterns in Apex
- Solve problems while instantiating, structuring and giving dynamic behavior to Apex classes
- Understand the implementation of creational, structural, behavioral, concurrency and anti-patterns in your application
- Follow the Apex best practices to resolve governor limit issues
- Get clued up about the Inheritance, abstract classes, polymorphism in Apex to deal with the object mechanism
- Master various design patterns and determine the best out of them
- Explore the anti patterns that could not be applied to Apex and their appropriate solutions
In Detail
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
Style and approach
This book is a step-by-step guide, complete with well-tested programs and real world situations to solve your common occurring problems in Apex design by using the anti-patterns. It gets crackling from exploring every appropriate solution to comparing the best one as per OOps principal.
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Seitenzahl: 241
Veröffentlichungsjahr: 2016
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Table of Contents
Apex Design Patterns
Apex Design Patterns
Copyright © 2016 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: April 2016
Production reference: 1220416
Published by Packt Publishing Ltd.
Livery Place
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Birmingham B3 2PB, UK.
ISBN 978-1-78217-365-6
www.packtpub.com
Credits
Authors
Jitendra Zaa
Anshul Verma
Copy Editor
Rashmi Sawant
Reviewer
John M. Daniel
Project Coordinator
Nidhi Joshi
Commissioning Editor
Julian Ursell
Proofreader
Safis Editing
Acquisition Editor
Nadeem Bagban
Indexer
Priya Sane
Content Development Editor
Aishwarya Pandere
Production Coordinator
Shantanu N. Zagade
Technical Editor
Madhunikita Sunil Chindarkar
Cover Work
Shantanu N. Zagade
About the Authors
Anshul Verma has been working on the Salesforce platform since 2006. Prior to that, he has done extensive development using MS technologies on web, desktop, and mobile applications. He possesses a tremendous understanding of enterprise-scale systems and has worked in designing intricate systems with high scalability, performance, and robustness. He has been a Dreamforce speaker and is a regular contributor to Stack Exchange and other developer communities. He has four Salesforce certifications and is currently working as a project manager and technical architect where he is responsible for managing customer success and delivering high-quality solutions to his clients. He has conducted various training sessions in his current organization and trained over 50 new hires. He is very popular with his training batches and can be often found sharing his knowledge with his team and peers. He owns and maintains his blog (http://mightycoder.blogspot.com/), and you can follow him on Twitter at @toanshulverma.
Jitendra Zaa has been working on the Salesforce platform since 2008. He has extensively worked on Java and .NET-based enterprise applications. He also has experience in working with multiple JavaScript libraries, web frameworks, ETL tools, and databases. He is an expert in designing and implementing integrations of Salesforce with external systems. He is a regular speaker at the world’s biggest developer event, Dreamforce, mostly in developer track. Because of his contributions to the Salesforce community, he has also been awarded the Salesforce MVP title. He has more than eight Salesforce certifications and works as a Salesforce technical architect. He owns one of the most viewed Salesforce developer blogs (http://www.JitendraZaa.com), formerly, http://Shivasoft.in. You can follow him on Twitter at @JitendraZaa.
About the Reviewer
John M. Daniel has been working in the technology sector for over 20+ years. During that time, he has worked with a variety of technologies and project roles. Currently, he works at FinancialForce.com with their Consulting/Product Services teams. He currently holds multiple certifications from Salesforce.com, including the Platform Developer I and II certifications and the Advanced Developer certification. He is currently in the process of attaining the Certified Technical Architect certification. He loves to spend time with his family, swim at the beach, and work on various open source projects, such as ApexDocs and ApexUML. He co-leads his local area Salesforce Developers User Group and can be found on Twitter at @ImJohnMDaniel.
John has been a technical reviewer for Force.com Enterprise Architecture, by Andrew Fawcett and Learning Apex Programming, by Matt Kaufman and Michael Wicherski, both by Packt Publishing.
I would like to thank my wife, Allison, for always giving me the freedom to pursue my interests.
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Preface
It was spring 2015; we were both discussing our presentation for Dreamforce 2015. During the discussion, we stumbled on the topic of the usage of design patterns in Apex. We observed that design patterns are still not extensively used in the Apex programming arena. We think that a few prominent factors for this situation are that there are not enough resources available around the design pattern implementation in Apex. Secondly, most of the Apex programmers who started their development career with Force.com have less exposure to other development platforms. Thirdly, some of the design patterns simply do not apply to Force.com development platforms.
As per our observation, the usage and mention of design patterns in day-to-day programming is reduced in Apex as compared to other development platforms. Developers coming from other programming backgrounds mostly have a working experience with design patterns and it's implicit for them to use it in their code style and design.
We realized that it would be even better to develop content around the design pattern implementation in a language that Apex developers can easily relate to. We positively think that by providing scenarios that are specific to Apex development use cases, developers will be able to understand and implement the design patterns in Apex with ease.
To ensure that we are able to provide information uniformly to all Apex developers irrespective of their experience level, this book also includes general programming best practices, programming principles, OOP concepts, and the usual pitfalls at appropriate places.
In line with our past experience with design pattern learning and implementation is the problem of memorizing the design patterns and situations where they fit in. However, in this book, we took real-life scenarios to explain a situation where an appropriate design pattern will be applied. One can easily relate the design pattern with an example given in this book to identify when it is the time to use that pattern.
Some open source GitHub repository links, Salesforce official developer blogs, and other tips have been shared throughout the book, which can be very helpful in Force.com project development.
What this book covers
Chapter 1, An Introduction to Apex Design Pattern, covers the basics of inheritance, abstract classes, polymorphism, cohesion and coupling, and object-oriented design principles.
Chapter 2, Creational Patterns, focuses on different ways to instantiate objects to achieve code reusability, ease of maintenance, and loose coupling.
Chapter 3, Structural Patterns, explains the design patterns that can solve many situations and problems, which occur during project development in Apex, that demand a change in functionalities and cause a ripple effect on the rest of the system.
Chapter 4, Behavioral Patterns, provides a glimpse of some problems, such as double dispatch and code maintenance issues, and explains how to use appropriate design patterns to fix them.
Chapter 5, Handling Concurrency in Apex, discusses the design solution for the race condition in concurrency, which can result in data corruption without anyone noticing it.
Chapter 6, Anti-patterns and Best Practices, shows some common pitfalls observed during application development in Apex and suggested solutions.
What you need for this book
We need an Internet-enabled computer that is capable of running modern browsers supported by Salesforce. We can use the developer console in a browser to write the Apex code in Salesforce.
Interested readers can also use their favorite IDEs, such as Sublime Text, Eclipse, Welkins, Atom, Aside, Cloud9, or BrainEngine.
You will also need a free Salesforce developer account to try all the code snippets and examples provided in this book.
Who this book is for
This book is intended for all Apex developers who want to learn and enhance their Apex code designing skills by applying various design patterns. It can be considered as a stepping stone for beginners or intermediate-level Apex programmers by filling their arsenal with powerful design patterns.
Conventions
In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The AdminGoldSupportImpl and AdminPlatinumSupportImpl classes are written in the same way."
A block of code is set as follows:
public class Mario { public void ability(){ System.debug('I can Walk'); } public void info(){ System.debug('I am Mario'); } }Any command-line input or output is written as follows:
$ mkdir css $ cd cssNew terms and important words are shown in bold.
Note
Warnings or important notes appear in a box like this.
Tip
Tips and tricks appear like this.
For this book we have outlined the shortcuts for the Mac OX platform if you are using the Windows version you can find the relevant shortcuts on the WebStorm help page https://www.jetbrains.com/webstorm/help/keyboard-shortcuts-by-category.html.
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Questions
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Chapter 1. An Introduction to Apex Design Pattern
We assume that you are reading this book because you have encountered situations where you have had the same design requirement multiple times, or seen a repetitive problem that has always been solved with the same solution. Those design solutions that are applied again and again to the same type of problem are also known as design patterns.
To better understand the application of design patterns in everyday life, let's take a look at the example of the ATM machine. Every ATM machine needs to have a slot where an ATM card can be inserted, there is a keypad to enter a secret pin, and there is a panel from where the cash can be dispensed. This core functionality of an ATM machine can be considered as a design pattern. Some banks need extra functionalities, such as bill pay or mobile recharge, and they can simply extend this design pattern as per their requirements.
No one would like to reinvent the wheel if an industry-proven solution already exists for a problem, and using such a proven solution would save them time and effort. Furthermore, it also ensures a scalable, robust, and future-ready solution.
In this book, we will discuss the challenges in application development using Apex, common repetitive problems, and most accepted solutions. We have structured our content considering the Apex development platform and blended it with day-to-day challenges that we face during development.
We will first explain the common concepts of application development, which are the building blocks for design patterns. Understanding these concepts is very important as all the design patterns are combinations of one or more principles explained in a later section.
Innovation
It is not necessary that design patterns should fulfill all requirements so why can't we innovate our own better solution?
Yes, innovation is necessary; and certainly, we can come up with a better design and solution or even a new design pattern. Let's take the preceding example; instead of entering a secret pin, a user can use voice recognition for authentication purposes'. It may look cool to some people, but for many it may be a security concern. Speech recognition may not work because of different accents and so on. My point here is that innovation comes at a cost. In software industry, we don't always have the privilege of time because of project timelines and other dependencies.
Design patterns are age-tested and recommended techniques to address a given problem. They not only help in solving the problem at hand, but also address various possible offshoots of the central problem. Design patterns have also evolved as per requirements and will continue to do so.
Design patterns and learning
We are not suggesting that you have to use only design patterns. Every problem is unique and a design pattern can solve only some part of the problem. However, you need to think, design, and come up with your own version of an extended design. Design patterns are very generic and basic; they mostly guide you through the flow of the creation of an object or manipulate the behavior at runtime or structure your code. A design pattern is not a finished code solution, but it is a recommended code structure. Choosing the right design pattern for a given problem is very important and needs thorough understanding. With increasing use of design patterns, you can further enhance your development skills and understand how to best structure your code.
Object-Oriented Programming (OOP)
Any language that supports the following four pillars of Object-Oriented Programming is known as an Object-Oriented Programming (OOP) language:
