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SEARCH KEYWORD -- Method chaining

  Introduction to GoLang generics and advanced usage

Generics in Go allow you to write code that can work with multiple types of data, without having to write separate versions of the code for each type. This can make your code more flexible and easier to maintain, as you only need to write and test the code once, rather than maintaining multiple versions. To use generics in Go, you first need to define a type parameter, which is a placeholder for the type that the code will work with. For example, you might define a type parameter called "T" like...

   GOLANG,GENERICS     2022-12-17 05:12:21

  Ways to check existence of JavaScript object

The design of JavaScript is not so sophisticated. It's very easy for us to make mistakes if we are not very careful when using JavaScript. For example, to check the existence of JavaScript object. Now we want to check whether a global object myObj exists or not, if it doesn't exist, we declare it. The pseudo code for this is : if(myObj not exist){ declare myObj; } You may think it's very easy to write the code. In fact, it is much more difficult than we may think. Juriy Zaytsev says there are m...

   JAVASCRIPT,OBJECT,EXISTENCE     2020-09-12 02:14:02

  Ruby net-scp cannot scp multiple files with asterisk(*)

net-ssh/net-scp is a Ruby gem which can be used to scp files between different *nix machines. It's similar to how the *nix scp command. It can be used to scp a file or a directory. However, it seems it has some problem to scp multiple files using pattern *. For example, below script is supposed to download all files from remote directory to local directory: require 'net/scp' host = 'testmachine' login = 'testaccount' password = "testpassword" remote_path = '/tmp/remote...

   NET-SCP,RUBY,ASTERISK,MULTIPLE FILES     2016-10-20 03:00:13

  jsonSerialize() in extended class

Since PHP 5.4.0, there is a convenient interface JsonSerializable which can be used to indicate that a PHP object can be serialized to JSON object. It has only one method which should be implemented by any class which implements this interface. The method is named jsonSerialize(). It's really easy to serialize an object to JSON object. Here is one example: <?php class ArrayValue implements JsonSerializable { public function __construct(array $array) { $this->array = $array; ...

   JSON,jsonSerialize,Inheritance,extends     2014-07-26 05:54:00

  Java Concurrency Basics: CountDownLatch and CyclicBarrier

CountDownLatch CountDownLatch can be used in synchronizing behavior among threads, it makes one or more threads wait for some actions in other threads to be completed. It has a property count which defines how many countDown() need to be called before other threads which called await() to be waked up.  When a thread calls CountDownLatch.await(), the thread will be blocked until the value of count becomes 0. The initial value of count can be specified when creating the CountDownLatch instanc...

   JAVA,JAVA CONCURRENCY,COUNTDOWNLATCH,CYCLICBARRIER     2018-03-25 07:02:40

  Be careful about printing error as string in GoLang

In GoLang, we can format and produce string using fmt.Printf(), just like C, GoLang also supports format verbs like %s, %d which can be placeholder for different types of values. But please pay attention when printing error as string so that you will not fall into some trap. Let's first take an example code snippet and see what trap we are talking about. package main import "fmt" type A string func (a A) Error() string { return fmt.Sprintf("%s is an error", a) } func main() { a := A("hello...

   STACKOVERFLOW,GOLANG,FMT     2019-01-23 09:17:15

  Java AbstractMethodError explained and demonstrated

According to Oracle Java API documentation, AbstractMethodError is a kind of runtime error where the application is having some incompatible changes which leads to a missing implementation of an abstract method. Below is the official description. Thrown when an application tries to call an abstract method. Normally, this error is caught by the compiler; this error can only occur at run time if the definition of some class has incompatibly changed since the currently executing method was last co...

   JAVA,ABSTRACTMETHODERROR     2016-07-22 22:03:20

  How to check whether a struct implements an interface in GoLang

Unlike other programming languages like Java, when implementing an interface in GoLang, there is no syntax like below to explicit tell the relationship: type I interface { } type A struct implements I { } When looking at the code or running the code in GoLang, it might lead to a case one doesn't know whether a struct implements interface before trying to use it as some interface. According to GoLang spec, as long as a struct implements all functions of an interface, it is considered as having i...

   GOLANG,INTERFACE,IMPLEMENTATION,CHECK     2020-05-03 00:05:54

  Traditional recursion vs Tail recursion

Recursion is a frequently adopted pattern for solving some sort of algorithm problems which need to divide and conquer a big issue and solve the smaller but the same issue first. For example, calculating fibonacci  accumulating sum and calculating factorials. In these kinds of issues, recursion is more straightforward than their loop counterpart. Furthermore, recursion may need less code and looks more concise. For example, let's calculate sum of a set of numbers starting with 0 and st...

   ALGORITHM,RECURSION,TAIL RECURSION,TRADITIONAL RECURSION     2016-09-23 23:54:09

  A return to good code

Stop doing this:public boolean foo() { if (true) {   return true;   }  else {   return false;   }}It always amazes me when I dig into an open source project, and I see code written by supposed experts, and reviewed by seasoned professionals, and nobody slaps the wrists of the developer who shoves return statements right in the middle of a method.Tell me, how hard is it to do this:public boolean foo() {   boolean flag = true;  ...

   Java,Code,Method,Return,Condition     2011-03-23 01:24:47

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