Lab 3

🖥 Lab 3: Exploring Kotlin Fundamentals

This lab is designed to provide hands-on experience with object oriented programming, collections, and the standard library in Kotlin.

 

📝 Objectives

1. Open the lab-3 project in Android Studio

2. Open Functions.kt and update/implement the functions there to make the tests in FunctionTests.kt pass

3. Open Loggers.kt and implement the interfaces, classes, and functions required to make the tests in OOPTests.kt pass

   1. You'll need to implement a Logger interface
   2. You'll need a BasicLogger Object class that implements Logger
   3. You'll need a FancyLogger class that implements Logger
   4. You'll need an extension function on the BasicLogger class to log multiple messages at the same time

4. Open SupportedLanguages.kt and update/implement the code to make the tests in SealedClassTests.kt pass

   1. You'll need to add a InvalidNameException and EmptyNameException to the SupportedAndroidLanguageException sealed class

5. Open CollectionsProcessing.kt and update/implement the function to make the tests in CollectionsTests.kt pass

 

✨ Challenges

Create an "Extra Fancy" Logger

1. Create an ExtraFancyLogger class that extends FancyLogger.
2. It should specify both a logTag and a separator.
3. It should override the log() implementation to use both properties when logging the message.

Create an extension function

Create an extension function on BasicLogger to print all elements of a List.

1. It should take in a List<String>
2. It should print each message using BasicLogger.log()

 

🖥 Lab 3 Hints: Exploring Kotlin Fundamentals

 

💡 Filtering values from a Collection

The Kotlin Standard Library has several helpful functions for filtering values from a collection:

1. filter{} The generic filter function takes a lambda allowing you to specify your own filtering criteria
2. filterNotNull() Will filter out any null values

 

💡 Extending a class

Class in Kotlin are closed for extension by default. To extend a class you must do 1 of 2 things

1. Make the base class abstract
2. Mark the base class as open for extension by adding the open modifier to the class declaration

 

💡 Extending a method

Like classes, methods in Kotlin are closed for extension be default.

To mark a method as being open for extension in child classes, add the open modifier to the method declaration