kotlin-features

Showcase of uncommon usage of typical Kotlin features

LocalDate / LocalDateTime

• Extension functions for destructuring declaration
• Simple DSL for creating of LocalDate and LocalDateTime: 17 January 2024 at 13:40 and 50.seconds
• Arithmetics for LocalDateTime: dateTime - 14.minutes + 50.seconds
• LocalDate range: fromDate..toDate, fromDate unitl toDate, fromDate downTo toDate step 2
• Comparison of LocalDates: > < >= <= == != === !==
• LocalDateTime in LocalDate
• fun Random.Default.nextLocalDate(from = LocalDate.MIN, to = LocalDate.MAX): LocalDate

Delegation

• Lazy function by lazy { }
• Example for implementing by EmailAddress()
• QueryBuilder example

Enhanced Extension Properties

• Extensions properties using WeakHashMap for storing data

Showcase of interesting functions from Kotlin Standard Library

Build functions

• buildList
• buildSet
• buildMap
• buildString

Collection functions

• slice
• associate, associateBy, associateWith
• groupBy, groupingBy
• chunked
• windowed
• partition
• joinToString, joinTo
• zip, unzip, zipWithNext
• reduce, runningReduce
• fold, scan
• subtract, union, intersect

Measuring time

• measureTime { }
• measureTimedValue { }
• markNow()

Utilities

• require, requireNotNull
• check, checkNotNull
• error
• repeat, use
• Delegates.observable, Delegates.vetoable