投稿時間:2023-08-23 20:17:28 RSSフィード2023-08-23 20:00 分まとめ(18件)

カテゴリー等	サイト名等	記事タイトル・トレンドワード等	リンクURL	頻出ワード・要約等/検索ボリューム	登録日
TECH	Techable（テッカブル）	静岡県の道路工事現場で“AIによる交通誘導警備”のデモ実施。警備業務をDX化し、県内初の認可を目指す	https://techable.jp/archives/217789	工事現場	2023-08-23 10:00:15
python	Pythonタグが付けられた新着投稿 - Qiita	Pythonプログラムの基本（ライブラリの使用、WEB情報の取得）	https://qiita.com/okamoto0/items/5562f94b2e92dac48d3e	visualstudio	2023-08-23 19:16:29
AWS	AWSタグが付けられた新着投稿 - Qiita	AWS SSM Agent v2からv3へアップデートする手順	https://qiita.com/tkhs1121/items/d0b98a67558c2440ef42	awsssmagentv	2023-08-23 19:46:10
海外TECH	MakeUseOf	Light Mode vs. Dark Mode: What Should You Use on Your iPhone or iPad?	https://www.makeuseof.com/light-mode-vs-dark-mode-on-iphone/	share	2023-08-23 10:16:23
海外TECH	MakeUseOf	Understanding State Management in Svelte Applications	https://www.makeuseof.com/svelte-state-management/	reliable	2023-08-23 10:00:25
海外TECH	MakeUseOf	Spotify vs. Apple Music: The Key Differences You Need to Know	https://www.makeuseof.com/spotify-vs-apple-music-key-differences/	Spotify vs Apple Music The Key Differences You Need to KnowSpotify and Apple Music offer similar libraries and features but what are the main differences between both platforms Keep reading to find out	2023-08-23 10:00:25
海外TECH	DEV Community	Next.js Hangout Thread	https://dev.to/vulcanwm/nextjs-hangout-thread-1n48	Next js Hangout ThreadHey this is the th weekly hangout thread This is a post where you can discuss anything related to Next js You can also share anything new you ve worked on with Next js or any new articles you ve created which talk about Next js Feel free to ask any questions as well	2023-08-23 10:37:24
海外TECH	DEV Community	Singleton Design Pattern in C#: Full Guide	https://dev.to/bytehide/singleton-design-pattern-in-c-full-guide-12f0	Singleton Design Pattern in C Full GuideHave you ever wondered how to maintain a unique instance throughout the lifecycle of an application and ensure that one class only has one instance Here s the magic word for you Singleton Specifically we ll explore each twist and turn of the Singleton journey in C Ready to dive in Let s get started Understanding Singleton in C Singleton as a design pattern is quite the stalwart in the world of Object Oriented Programming languages and definitely in C Let s dig a little deeper into the rich soil of this concept and see what gems we can unearth Concept of Singleton Class in C A singleton is like a deck of cards handy compact but up there can only be one Ace of Spades Singleton classes are of utmost importance when only one instance of a class is to be created In the bustling city of C development this intelligent design model finds usage in multiple scenarios be it representing a single DB connection shared by multiple objects or reading a configuration file public sealed class Singleton private static Singleton singleton null private static readonly object singletonLock new object Singleton public static Singleton SingleInstance get lock singletonLock if singleton null singleton new Singleton return singleton Got to say C sure makes things neat In the above code snippet we ve got a Singleton class Notice the sealed keyword That s how we ensure no other class can inherit from our Singleton keeping it truly one of a kind The SingleInstance method here acts like the gatekeeper loyally providing only one instance of our Singleton keeping sure it is safely locked and thread safe More on thread safety later Now imagine you have a chocolate stash you don t want to share who wants to share chocolate right Our Singleton class behaves kind of like that By creating only one instance it safeguards resources by keeping that instance locked away only accessible via its very own property SingleInstance But let s simplify this and get a better grip of Singleton by crafting another basic yet illustrative application Mechanism of Singleton ClassSingleton class in technical terms is a way to provide one and only one object of a particular type But let s illustrate this with an example that we can all relate to Imagine you re at a movie theatre There s only one projector that plays the movie right That s exactly what Singleton is Let s code a Projector Singleton class public sealed class Projector Private object instance of the class initialized to null private static Projector instance null Object for lock functionality private static readonly object lockObject new object Private constructor ensures instances can t be made elsewhere private Projector Property to get the instance of Projector public static Projector Instance get Locking the block of code where instance is created lock lockObject This will be null the first time this piece of code runs if instance null instance new Projector return instance Some projector method public void Display Console WriteLine Displaying movie In this analogy we have a Singleton Projector class Any cinema in our application trying to play a movie has to access this single projector instance They can t get another projector or create a new one there s only one projector available and the Singleton Design Pattern ensures that Here s how we call it Get the singleton instanceProjector projector Projector Instance Call any of its methodsprojector Display Just like in any theatre once the movie starts playing every audience is watching the same one And our Singleton Projector ensures that Exploring Singleton Design Pattern in C So you ve heard about Singleton Design Pattern right We re going to dive deeper into this fascinating topic right now Just like a car Singleton Design Pattern takes tiny pieces our Singleton class and builds a vehicle that drives our codes with efficiency and pace Singletons ensure that we have one and only one instance of a class throughout our application Application Scenarios of Singleton Design PatternSingleton Design Pattern is a useful tool in many scenarios kind of like a Swiss Army Knife Think of it like this whenever a class needs to have only one instance and this instance requires global access Singleton comes to the rescue Now that s a superhero From logging services thread pools device drivers to configuration settings and caching Singleton powers an impressive range of applications Let s throw some light on how it helps with logging public sealed class Logger private static Logger instance null private static readonly object padlock new object Logger public static Logger Instance get lock padlock if instance null instance new Logger return instance public void LogMessage string message Code to log message In this code we re creating a Logger singleton Imagine the Logger as a note taker who writes down events happening in your classroom program You want to make sure there is only one note taker Otherwise the notes might differ and cause confusion The same principle applies here Through Singleton only one instance of Logger takes care of logging Now let s introduce another Singleton instance Database Connection It s costly and time consuming to keep opening and closing database connections Here comes our Singleton class to the rescue manage only one connection at a time public sealed class SingletonDbConnection private static SingletonDbConnection instance null private SingletonDbConnection public static SingletonDbConnection Instance get if instance null instance new SingletonDbConnection return instance public void RunQuery string query Code to execute the SQL query Here Singleton ensures that only one database connection is active at a time just like how using a single pen can help you maintain neat handwriting throughout your notes Adapting Adapter Pattern in C Sometimes you might come across classes that are not compatible with each other kind of like trying to put a square peg in a round hole Adapter Pattern acts as a link to make these classes work together Adapter Pattern Vs Singleton Design PatternIt s easy to mix up Adapter pattern with Singleton They re both design patterns but they are as different as chalk and cheese While Adapter Pattern is focused on making different classes work together Singleton Design Pattern ensures only one instance of a class exists Imagine the Adapter Pattern as a universal travel adapter that lets you use devices from different countries in one socket On the other hand Singleton is like that one golden ticket in a chocolate barーthere s only one but everyone can use it So when should you use one over the other You d reach for the Adapter Pattern when you need to make incompatible interfaces work together kind of like using a USB C to USB A adapter to connect your modern laptop with older devices Singleton Pattern is more like your WiFi connection there s only one signal but everybody can use it up to its capacity of course The Composition of a C Singleton ClassImagine if you will a pizza A pizza is great but it takes more than just crust to make a good one right We need toppings lots of them Similarly a Singleton class is comprised of several key ingredients or elements Let s see how this pizza analogy applies to our C Singleton class piece by piece Breaking Down the Structure of Singleton ClassJust like how a delicious pizza has the right balance of crust sauce cheese and toppings a Singleton class in C at its core is made up of three main components A private static instance of the class itself A private constructor A public static method that returns the instance of the class Let s look at this in the context of a simple code example public sealed class Singleton private static Singleton instance null Private Instance private Singleton Private Constructor public static Singleton Instance Public Method get if instance null instance new Singleton return instance Think of it this way the static instance is like the pizza crust acting as the base of our class The private constructor is like the sauce It s a key component but you don t interact with it directly when you eat the pizza Finally the public static Instance method is like the cheese it s what you interact with and helps hold everything together The null is initially assigned to the instance When the Instance method is called for the very first time it creates a new Singleton object But for any subsequent requests it s like asking for a slice of already baked pizza you simply return the same slice or instance you had before C Singleton A Practical ExampleThink of a printer Ideally in an office you would want all print requests to go to a single centralized printer There should only be one instance of a printer and everyone gets their print jobs from this single source Code Walkthrough Implementing SingletonLet s code this out and see how it works public sealed class Printer private static Printer instance null This is our single printer Initially it doesn t exist null private Printer This is where we set up our printer But note that it s private Only this Printer class can setup the printer public static Printer Instance This is how people request to use the printer get This part checks if the printer exists if instance null If it doesn t it sets up a new printer instance new Printer Whether it just set up a new printer or one already existed it returns the printer return instance Just like requesting a pizza slice whenever you want to print something you call Printer Instance No matter how many times you call it you are always returned the same unique single printer It doesn t create the printer anew for every request but instead it reuses the pre existing one Neat huh It s as simple as that Want to print something Call Printer Instance and you ll get the single unique printer ready to serve your documents The Importance of Thread Safety in C SingletonThread safety in Singleton design is a crucial cornerstone to grasp It s like making sure there s only one captain steering the ship no matter how choppy the waters Why Thread Safe Singleton is a MustIn the world of programming more than one thread trying to access a resource simultaneously may result in what we call a race condition a chaos equivalent to letting two drivers control a car simultaneously Therefore when multiple threads could potentially create multiple instances of our singleton class it violates the fundamental principle of the Singleton pattern one and only one instance public sealed class ThreadSafeSingleton private static ThreadSafeSingleton instance null private static readonly object lockCheck new object private ThreadSafeSingleton public static ThreadSafeSingleton Instance get lock lockCheck if instance null instance new ThreadSafeSingleton return instance In this simple yet effective code example the lock keyword is like the bouncer at the entrance of a club admitting one person in or one thread into the block of code at a time Even when multiple threads try to access it at once only one gets through making sure the instance once created is the one and only Fine Tuning Thread Safe Singleton The Double Check LockingLet s make this example even better Double check locking is a technique that further optimizes our thread safe Singleton public sealed class ThreadSafeSingleton private static ThreadSafeSingleton instance null private static readonly object lockCheck new object private ThreadSafeSingleton public static ThreadSafeSingleton Instance get if instance null lock lockCheck if instance null instance new ThreadSafeSingleton return instance Twist in the plot Why the double check you ask Because we want to avoid the costly lock operation when the instance isn t null which would be most of the times after the initial few calls The NET way LazyBut hold on we re in the world of C and there s a simpler more effective way to keep our Singleton thread safe The NET Framework provides Lazy lt T gt that makes laziness a virtue public class Singleton private static readonly Lazy lt Singleton gt lazyInstance new Lazy lt Singleton gt gt new Singleton private Singleton public static Singleton Instance get return lazyInstance Value The Lazy lt T gt provides support for lazy initialization When multiple threads try to access it Lazy lt T gt ensures that only one of them can call the Singleton constructor And the rest simply wait patiently and are then allowed to carry on using the instance once it s been created Dependency Injection and C addSingletonDependency Injection you might compare it to a castle s foundation Just as a builder ensures that the foundation of a castle is solid so that the rest of the construction can be successful Dependency Injection provides a solid base for our objects Let s think of it like this it works like your friendly neighborhood mailperson delivering right what is needed or should we say…dependencies Its job It gives an object all the other objects it needs to do its job So how does addSingleton fit into this picture Think of addSingleton as our super special delivery guy who ensures everyone gets exactly the same copy of today s hot off the press newspaper Once addSingleton delivers a dependency it stays consistent throughout the application run Now isn t that neat Introduction to Dependency Injection and addSingletonImagine having a town mayor also known as our application This mayor interacts with many other townsfolk also known as classes or objects and she is very popular so she doesn t go to them directly Instead she has a message carrier who relays the news or…dependencies to everyone This carrier is what we call Dependency Injection DI DI follows a simple principle it keeps related things together and unrelated things apart It reduces the dependent code makes the code more manageable testable and promotes loose coupling which is a good coding practice Now the Singleton method is a unique pattern where an object is created only once meaning everyone gets the same copy and we use the AddSingleton method of NET Core to ensure this Let s get a bit practical and let C do the talking public void ConfigureServices IServiceCollection services services AddSingleton lt IMyService MyService gt This snippet is a shiny example of AddSingleton The AddSingleton function tells the application to build an object one time and one time only and use the same instance for every future request Consider IMyService like a newspaper and AddSingleton as our special delivery guy delivering IMyService everywhere in the city our application Every time anyone asks for IMyService they get MyService delivered to them fresh from the press It s like saying “Hey If anyone asks for IMyService give them MyService and always give them the same one Now let s extend our notion with another example Imagine you have an application where you need to access a database IDatabaseService to get data public interface IDatabaseService IEnumerable lt string gt GetData public class DatabaseService IDatabaseService public IEnumerable lt string gt GetData Add code here to retrieve data from database return new List lt string gt Sample Data public class HomeController Controller private readonly IDatabaseService databaseService public HomeController IDatabaseService databaseService databaseService databaseService public IActionResult Index var data databaseService GetData return View data public void ConfigureServices IServiceCollection services services AddSingleton lt IDatabaseService DatabaseService gt In this example we first define an IDatabaseService which fetches data from a database We have a DatabaseService class implementing this interface We have a HomeController which needs access to the database and so receives IDatabaseService as a parameter in its constructor This HomeController doesn t care about who provides IDatabaseService or how it is created all it knows is that it needs IDatabaseService to do its work making the system more modular and testable Now when HomeController requests IDatabaseService instead of creating a new DatabaseService every time the DatabaseService which was freshly created and stored by AddSingleton is supplied Singleton Pattern in Game Development C UnityGet ready to dive headfirst into the world of gaming applications with Unity and Singleton Unity is a powerful game development engine and learning Singleton within its context can unlock some superpowers to create more efficient game mechanics Are you keen to learn We ve got a lot to cover Application of Singleton in UnityIn Unity Singleton might wear a slightly different look but it still carries the same purpose to avoid multiple script instances from running Now this concept may sound a bit tricky initially but let s break it down and understand it better public class GameManager MonoBehaviour Static instance stored public static GameManager instance Called when the script instance is being loaded void Awake if instance null Destroy gameObject Ensures only one instance is available else instance this DontDestroyOnLoad gameObject Remaining code of game manager Imagine playing a video game where our character GamePlayer needs to interact with the GameManager The GameManager is a Unity GameObject that controls different aspects of the game like keeping track of player s life loading different levels etc Now it s a pickle if there are multiple GameManagers to manage a single GamePlayer right That s where Singleton comes in It ensures that only one instance of GameManager exists throughout the game scenes How does it work here The script first checks if an instance of the GameManager already exists If it does it destroys the new GameObject attempting to create a fresh new GameManager If it doesn t it assigns the instance variable to the new GameManager Let s say we have another GameObject in the game say Enemy Enemy needs information from GameManager to interact with the GamePlayer How will it access the singleton GameManager public class Enemy MonoBehaviour Reference to game manager GameManager gameManager void Start gameManager GameManager instance Assigns gameManager from Singleton instance void Update Use gameManager to interact with GamePlayer In the above Enemy class script it s seen that we can easily access the GameManager singleton instance We first create a GameManager reference and on Start we assign it with our Singleton GameManager instance Now Enemy can comfortably interact with GamePlayer via this singleton GameManager throughout the game Isn t it wonderfully simple once we understand the process Leveraging C Services addSingletonTo round off our Singleton its quest in C let s do a bit more digging into the addSingleton method under the services of C Remember the Singleton class we created before We re giving it a turbo boost using C services The Power of C Services addSingletonThe addSingleton method revs up our Singleton s engine in ASP NET Core by keeping it alive throughout the application run exactly what a Singleton aims for public void ConfigureServices IServiceCollection services services AddSingleton lt IEmailService EmailService gt In this code snippet we re ordering ASP NET Core to maintain a single instance of EmailService throughout the lifespan of the application Like a one stop shop every time IEmailService is requested EmailService is at your service Now let s understand this better with a simple example Imagine you re at a fast food restaurant and ordering a meal You ask for a burger that s your IEmailService The restaurant our application only has one kind of burger the EmailService So every time you ask for a burger you re served the EmailService burger Can you ask for a different one Nope There s only one type and it s ready to be served as long as the restaurant application stays open C Services addSingleton In Action A Practical ExampleLet s take another real life scenario Let s say we re developing a blog website For simplification we will consider that the blog posts will be written by a single author Hence the author s information remains consistent throughout the application making AuthorInformation a perfect candidate for a Singleton service public class AuthorInformation public string Name get set public string Email get set First we create an AuthorInformation class with a few properties Then we register AuthorInformation as a Singleton service in Startup cs file public void ConfigureServices IServiceCollection services services AddSingleton lt AuthorInformation gt Every time somewhere in our application if the AuthorInformation is requested the ASP NET Core serves the same instance we asked for Summing Up with C Services addSingletonIn conclusion the addSingleton method does just what we d hope from a Singleton design pattern in ASP NET Core It gives us a single persistent instance throughout our application s runtime With that we ve explored how deep the Singleton rabbit hole goes in C While it seems like a lot to digest remember practice makes perfect Keep coding and you ll turn into a C Singleton maestro sooner than you think The Singleton journey doesn t stop here however There are many more voyages awaiting you in the vast ocean of C each one richer than the last As always code wisely explore freely and most importantly enjoy the ride	2023-08-23 10:01:24
Apple	AppleInsider - Frontpage News	Feds seize $400,000 worth of counterfeit Apple devices	https://appleinsider.com/articles/23/08/23/feds-seize-400000-worth-of-counterfeit-apple-devices?utm_medium=rss	Feds seize worth of counterfeit Apple devicesCounterfeit Apple products including AirPods and hundreds of the Apple Watch worth almost have been seized in Federal raids at both the Long Beach Seaport and Ontario International Airport Counterfeit Apple Watch source NBC Federal authorities have announced that the counterfeit devices arrived from Hong Kong in six separate shipments They were all intercepted in one week in July Read more	2023-08-23 10:38:10
海外科学	NYT > Science	India Moon Landing: In Latest Moon Race, India Aims to Claim First Successful Southern Pole Landing	https://www.nytimes.com/live/2023/08/23/science/india-moon-landing-chandrayaan-3	India Moon Landing In Latest Moon Race India Aims to Claim First Successful Southern Pole LandingDays after a Russian lunar landing failed India will try to explore with its Chandrayaan spacecraft an area of the moon that has yet to be visited Watch live video here around a m Eastern	2023-08-23 10:55:30
医療系	医療介護 CBnews	出産費用「見える化」サイト、厚労省がイメージ-平均負担額などを施設ごとに集計・掲載	https://www.cbnews.jp/news/entry/20230823193719	厚生労働省	2023-08-23 19:56:00
医療系	医療介護 CBnews	特定行為研修修了者の配置、介護施設で2.2％のみ-研修緩和など求める声、医道審・部会	https://www.cbnews.jp/news/entry/20230823192901	介護施設	2023-08-23 19:43:00
ニュース	BBC News - Home	British Museum safety claims 'opportunistic' - MP	https://www.bbc.co.uk/news/uk-66592354?at_medium=RSS&at_campaign=KARANGA	greek	2023-08-23 10:34:58
ニュース	BBC News - Home	Women's World Cup 2023: Megan Rapinoe criticises Spanish football federation and United States critics	https://www.bbc.co.uk/sport/football/66590777?at_medium=RSS&at_campaign=KARANGA	Women x s World Cup Megan Rapinoe criticises Spanish football federation and United States criticsFemale footballers campaigning for equality means they are playing two games at the same time says former United States international Megan Rapinoe	2023-08-23 10:22:25
IT	週刊アスキー	『グラブル リリンク』が2024年2月1日に発売決定！本日より予約受付スタート	https://weekly.ascii.jp/elem/000/004/151/4151632/	cygames	2023-08-23 19:40:00
IT	週刊アスキー	シリーズ最新作『リトルナイトメア3』が制作決定！2人の新主人公が悪夢を彷徨う	https://weekly.ascii.jp/elem/000/004/151/4151608/	nintendo	2023-08-23 19:10:00
IT	週刊アスキー	PayPay、台湾のキャッシュレス決済サービスと連携	https://weekly.ascii.jp/elem/000/004/151/4151633/	esunwallet	2023-08-23 19:45:00
IT	週刊アスキー	CData Syncがアップデート GA4の使いやすいビューやデータマスク機能をリリース	https://weekly.ascii.jp/elem/000/004/151/4151630/	cdatasoftwarejapan	2023-08-23 19:30:00