Tutorial by Examples: in

OOP - Object Oriented Programming is a vastly used programming paradigm in these days. In OOP, we model real world problems using Objects and there behaviors, in order to solve them, programmatically. There are four main OOP Concepts Inheritance Polymorphism Abstraction Encapsulation These...

To get the time at which your app was installed or updated, you should query Android's package manager. try { // Reference to Android's package manager PackageManager packageManager = this.getPackageManager(); // Getting package info of this application PackageInfo info = pack...

In Object Oriented Design, objects receive messages and reply to them. In Ruby, sending a message is calling a method and result of that method is the reply. In Ruby message passing is dynamic. When a message arrives rather than knowing exactly how to reply to it Ruby uses a predefined set of rules...

class Example def example_method :example end def subexample_method :example end def not_missed_method :example end def method_missing name return :example if name == :missing_example_method return :example if name == :missing_subexample_method ...

Ruby moves up on ancestors chain of an object. This chain can contain both modules and classes. Same rules about moving up the chain apply to modules as well. class Example end module Prepended def initialize *args return super :default if args.empty? super end end module Fi...

There are two ways to interrupt messages. Use method_missing to interrupt any non defined message. Define a method in middle of a chain to intercept the message After interrupting messages, it is possible to: Reply to them. Send them somewhere else. Modify the message or its result. ...

The Continue operator works in For, ForEach, While and Do loops. It skips the current iteration of the loop, jumping to the top of the innermost loop. $i =0 while ($i -lt 20) { $i++ if ($i -eq 7) { continue } Write-Host $I } The above will output 1 to 20 to the console but miss...

Using a file Swift let data = NSData(contentsOfFile: filePath) //assuming filePath is a valid path Objective-C NSData *data = [NSData dataWithContentsOfFile:filePath]; //assuming filePath is a valid path Using a String object Swift let data = (string as NSString).dataUsingEncoding(NSUTF8S...

To String Swift let string = String(NSString(data: data, encoding: NSUTF8StringEncoding)) //assuming data is a valid NSData object Objective-C NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; //assuming data is a valid NSData object [string release]; T...

void methods can be stubbed using the doThrow(), doAnswer(), doNothing(), doCallRealMethod() family of methods. Runnable mock = mock(Runnable.class); doThrow(new UnsupportedOperationException()).when(mock).run(); mock.run(); // throws the UnsupportedOperationException Note thatvoid methods...

This class is called Greeter. Its responsibility is to output a greeting. It has two dependencies. It needs something that will give it the greeting to output, and then it needs a way to output that greeting. Those dependencies are both described as interfaces, IGreetingProvider and IGreetingWriter....

This builds on the previous example of the Greeter class which has two dependencies, IGreetingProvider and IGreetingWriter. The actual implementation of IGreetingProvider might retrieve a string from an API call or a database. The implementation of IGreetingWriter might display the greeting in the ...

Dependency injection means writing classes so that they do not control their dependencies - instead, their dependencies are provided to them ("injected.") This is not the same thing as using a dependency injection framework (often called a "DI container", "IoC container&quo...

Name binding is a concept that allows to say to a JAX-RS runtime that a specific filter or interceptor will be executed only for a specific resource method. When a filter or an interceptor is limited only to a specific resource method we say that it is name-bound. Filters and interceptors that do no...

Connection factories are the managed objects that allows application to connect to provider by creating Connection object. javax.jms.ConnectionFactory is an interface that encapsulates configuration parameters defined by an administrator. For using ConnectionFactory client must execute JNDI lookup ...

Often we wish to convert, or transform the contents of a collection (a list, or something traversable). In Haskell we use map: -- Simple add 1 map (+ 1) [1,2,3] [2,3,4] map odd [1,2,3] [True,False,True] data Gender = Male | Female deriving Show data Person = Person String Gender ...

Given a list: li = [1,2,3,4,5] we can filter a list with a predicate using filter :: (a -> Bool) -> [a] -> [a]: filter (== 1) li -- [1] filter (even) li -- [2,4] filter (odd) li -- [1,3,5] -- Something slightly more complicated comfy i = notTooLarg...

From "How to use Truth" http://google.github.io/truth/ String string = "awesome"; assertThat(string).startsWith("awe"); assertWithMessage("Without me, it's just aweso").that(string).contains("me"); Iterable<Color> googleColors = googleLog...

In order to load the XML data with XOM you will need to make a Builder from which you can build it into a Document. Builder builder = new Builder(); Document doc = builder.build(file); To get the root element, the highest parent in the xml file, you need to use the getRootElement() on the Doc...

Writing to a XML File using XOM is very similar to reading it except in this case we are making the instances instead of retrieving them off the root. To make a new Element use the constructor Element(String name). You will want to make a root element so that you can easily add it to a Document. E...