Allen iOS Concurrency - Understanding DispatchQueue and OperationQueue

🙋🏻‍♂️ Self-Diagnosis Checklist

 

After the class, you will be able to clearly know and understand the following concepts.

• I have a clear understanding of the concept of Dispatch Queue. (Yes/No)
• I understand the types of DispatchQueues and Quality of Service (QoS). (Yes/No)
• I know why the Sync method should not be used in most cases, and I understand the difference regarding cases where the Sync method must be used. (Yes/No)
• I understand the concept of Dispatch Groups. (Yes/No)
• I know what to be careful about when dealing with asynchronous functions in a Dispatch Group. (Yes/No)
• I understand the concept of Dispatch Work Item and know why it is used. (Yes/No)
• Dispatch Semaphore I understand the concept of and know how to use it. (Yes/No)
• When designing objects, I clearly understand the precautions regarding the possibility of access by multiple threads and can design correct objects. (Yes/No)
• I clearly understand the points to be cautious about when handling asynchronous concepts while creating table view/collection view type projects that download images. (Yes/No)
• I clearly understand the problems that can occur when using Dispatch Queues (when multiple threads access data), especially Race Conditions, and I know how to use TSan (Thread Sanitizer Tool). (Yes/No)
• I clearly understand how to write thread-safe code. (Yes/No)
• I understand the concept of Operations, which are an extension of Dispatch Queues, and their differences. (Yes/No)
• I can distinguish and decide when to use OperationQueue instead of DispatchQueue. (Yes/No)
• I understand the code for AsyncOperation, which can handle asynchronous functions. (Yes/No)
• Key features of Operation (setting the order of tasks, cancellation) can be used freely. (Yes/No)

 

 

📝 Lecture Curriculum

 

(It consists largely of GCD and Operation sections. Even if you have a good understanding of GCD, you might be unfamiliar with Operation (Task Class), which is a concept evolved from GCD. I have structured this so that you can understand everything in one single lecture, more clearly and easily than any other blog or course.)

 

 

🖼️ Example of the visual explanation method

 

(These are examples of the various illustrations and diagrams used in the class.)

 

 

🌈 Materials provided in the lecture

 

The following various materials are provided.

1. GCD Summary PDF - 287 pages
2. Operation Summary PDF - 89 pages
3. Code for GCD-related explanations (Playground file) - 19 pages (excluding source files)
4. Code for Operation-related explanations (Playground file) - 8 pages (excluding source files)
5. iOS Project Files - 8 items
6. Translated versions of reference articles (2 types)

(All materials within the folder above are provided.)

 

 

🙌 Materials referenced for course creation

 

Although I referred to the materials below, all the diagram explanations were designed by myself.

1. Video Lecture (iOS Concurrency with GCD and Operations) - raywenderlich https://www.raywenderlich.com/3648-ios-concurrency-with-gcd-and-operations
2. Book(Concurrency by Tutorials) - raywenderlich https://store.raywenderlich.com/products/concurrency-by-tutorials
3. Article(Operation and OperationQueue Tutorial in Swift) - raywenderlich https://www.raywenderlich.com/5293-operation-and-operationqueue-tutorial-in-swift
4. Article(The thread safety of lazy variables in Swift) https://medium.com/what-i-talk-about-when-i-talk-about-ios-developmen/the-thread-safet y-of-lazy-variables-in-swift-b20184ef5a38

 

 

🙋🏻‍♂️ Is there a significant difference between the course content and the <Course Production References>?

 

There is a very significant difference.

If I had intended to create a lecture that was merely a simple translation of the reference materials above, I would not have planned this course. I have personally created efficient and effective explanations, direct illustrations, and diagrams using PPT for these topics, choosing the best method of explanation to help provide an intuitive understanding of how actual threads operate. As mentioned above, I have reviewed the reference materials more than 10 times each, and this lecture aims to cover all that content while making it much easier to understand through various intuitive illustrations.

 

And since the content of these illustrations was personally organized over a period of more than two months full-time, I believe you won't find this method of explanation or such detailed descriptions anywhere else (including overseas materials). For example, if there was a single line in the reference material (raywenderlich's video lecture) stating, “There may also be issues related to lazy var,” I have personally researched all issues related to lazy var, organized them, provided intuitive understanding through illustrations, and presented solutions.

 

Under the premise that once you understand the diagrams (the big picture), writing code becomes very easy, I have tried to maintain a balance between understanding through diagrams and practical application through code, which creates a significant difference from other reference materials. I would like to say that the clear points of differentiation are the much more detailed, intuitive, and abundant materials, along with consistent and easy-to-understand explanations compared to other resources.

 

 

🐠 Regarding the provided code

 

To help with understanding the topic, code files are provided and covered within the lesson content. Regarding the provided code, within the scope permitted by the license, I have adopted most of the code provided in Ray Wenderlich's GCD video lectures (the adopted parts are specified). For parts where the license is not permitted (code provided in Ray Wenderlich books), I have written the code myself, and the core parts are written similarly within a large framework to ensure the reliability of the provided code.

 

 

Additionally, to help you understand the provided code, I have rearranged the sequence and added numerous pieces of code for more detailed explanations, helping you grasp the course content through various examples.

 

 

🤔 Regarding the pricing of the class

 

You may find the price a bit high for a single topic, but I want to assure you that it contains so much content that you will experience satisfaction far exceeding the price. To explain this content, I am providing a total of 376 pages of PDF materials that I wrote myself, consisting of 287 pages on GCD and 89 pages on Operation. (The actual materials I use for explanation in the video lectures consist of about 830 PPT slides, excluding code.)

 

It covers almost everything related to GCD/Operation that can be found in international resources, and most of the illustrations and diagrams included in this course were created by me personally. A significant amount of time and effort went into this course, and because I believe it is such an important topic for a developer's future growth, I planned and created it based on the standard of (from my personal perspective) “I wish there were materials and a course like this.”

 

Additionally, from my personal perspective, I believe that deciding to pay for a lecture is a matter of exchanging time for money. I believe this course will serve as an effective way to save you study time on this topic relative to the cost, and it is my hope that you save time and achieve higher satisfaction. I will repay you with substantial content to provide satisfaction that exceeds the price, and I politely ask for your kind consideration of these points. ^^

 

 

💌 Regarding Lecture Content Licensing

 

In the contents of this lecture, for any instances where I have referenced drawings or other materials, the relevant URL addresses are provided in the PDF. Since all other materials except for those cases were created by me, I politely request that you include the URL of this lecture when summarizing the explanation methods on your blog or other platforms.

 

Nevertheless, including the overall content of this lecture on a blog or sharing the PDF files used as lecture materials is strictly prohibited under any circumstances.

 

 

 

👀 Providing a preview of the course content

 

Before you decide to take the course, we have made it possible for you to check the teaching style in advance.

• (Section 0. 1. Prior to GCD/Operation) and related approximately 1 hour of preview
• (Section 10. 1. Prior to Operation)-related preview of about 5 minutes

 

 

You can check out the lectures provided as previews and then decide whether to take the course. :)