Insert Koin

Koin is the next step to becoming a project only with Kotlin code. What inside Koin? Only DSL & Kotlin magic. It is possible to effectively replace Dagger 2? Let’s find out does Dependency Injection + Kotlin + Easy of Use == Koin?

Transcript

1. Kirill Rozov Android Developer
2. Dependency Injection
3. Inversion of Control (IoC) is a design principle in which custom-written portions of a computer program receive the flow of control from a generic framework wikipedia.org/wiki/Inversion_of_control
4. No IoC CLIENT CLIENT CLIENT DEPENDENCY 1 DEPENDENCY 2 DEPENDENCY 3 DEPENDENCY 4
5. With IoC DEPENDENCY 1 DEPENDENCY 2 DEPENDENCY 3 DEPENDENCY 4 IoC CONTAINER CLIENT CLIENT CLIENT
6. With IoC DEPENDENCY 1 DEPENDENCY 2 DEPENDENCY 3 DEPENDENCY 4 IoC CONTAINER CLIENT CLIENT CLIENT
7. Popular DI • Guice • Spring DI • Square Dagger • Google Dagger 2 • Java EE CDI • PicoContainer • Kodein • Koin
8. insert-Koin.io
10. Sample
11. Sample val sampleModule = module { single { ComponentA() } }
12. Sample val sampleModule = module { single { ComponentA() } }
13. Sample val sampleModule = module { single { ComponentA() } }
14. Sample val sampleModule = module { single { ComponentA() } } class Application : KoinComponent { val component by inject<ComponentA>() }
15. Sample val sampleModule = module { single { ComponentA() } } class Application : KoinComponent { val component by inject<ComponentA>() }
16. Sample val sampleModule = module { single { ComponentA() } } class Application : KoinComponent { val component by inject<ComponentA>() }
17. Sample val sampleModule = module { single { ComponentA() } } class Application : KoinComponent { val component by inject<ComponentA>() } fun main(vararg args: String) { startKoin(listOf(sampleModule)) }
18. Sample class SampleApplication : Application() { override fun onCreate() { startKoin(listOf(sampleModule)) } }
19. Provide dependencies module { single { ComponentA() } factory { ComponentB() } }
20. Provide dependencies module { single { ComponentA() } factory { ComponentB() } }
21. Provide dependencies module { single { ComponentA() } factory { ComponentB() } }
22. Provide dependencies class ComponentA(c : ComponentB)
23. Provide dependencies module { single { ComponentB() } single { ComponentA(get<ComponentB>()) } } class ComponentA(c : ComponentB)
24. Dependency Parameters
25. Properties class RestService(url: String)
26. Properties module { factory { RestService(getProperty(“url”)) } } class RestService(url: String)
27. Properties module { factory { RestService(getProperty(“url”)) } } class RestService(url: String) module { factory { RestService(getProperty(“url”, “http://localhost”)) } }
28. Properties module { factory { RestService(getProperty(“url”)) } } class RestService(url: String) module { factory { RestService(getProperty(“url”, “http://localhost”)) } } val key1Property: String by property(“key1”)
29. Properties Sources
30. Properties Sources • On initialization
31. Properties Sources • On initialization • Using KoinComponent.setProperty()
32. Properties Sources • On initialization • Using KoinComponent.setProperty() • koin.properties in assets
33. Properties Sources • On initialization • Using KoinComponent.setProperty() • koin.properties in assets • koin.properties in JAR resources
34. Properties Sources • On initialization • Using KoinComponent.setProperty() • koin.properties in assets • koin.properties in JAR resources • Environment variables
35. Problem class NewsDetailPresenter(newsId : String)
36. Parameters val presenter: NewsDetailPresenter by inject { parametersOf(“sampleNewsId") }
37. Parameters module { factory { (id : String) -> NewsDetailsPresenter(id) } } val presenter: NewsDetailPresenter by inject { parametersOf(“sampleNewsId") }
38. Parameters module { factory { (id : String) -> NewsDetailsPresenter(id) } } val presenter: NewsDetailPresenter by inject { parametersOf(“sampleNewsId") }
39. Names
40. Duplicated dependencies module { single { ComponentB(…) } single { ComponentB(…) } }
41. Named dependencies module { single(name = “debug”) { ComponentB(…) } single(name = “prod”) { ComponentB(…) } }
42. Named dependencies class Application : KoinComponent { val componentProd by inject<ComponentB>(“prod”) val componentDebug by inject<ComponentB>(“debug”) } module { single(name = “debug”) { ComponentB(…) } single(name = “prod”) { ComponentB(…) } }
43. Named dependencies module { single(name = “debug”) { ComponentB(…) } single { ComponentA(get(“debug”)) } }
44. Namespaces
45. Namespaces module { … }
46. Namespaces module(path = “”) { … }
47. Namespaces val rootModule = module { … } val sampleModule = module(path = “org.sample”) { … }
48. Namespaces module { module(“org.sample”) { } }
49. Namespaces module { module(“org.sample”) { } }
50. Namespaces module(path = “org.sample”) { … } // is equals to module { module(“org”) { module(“sample”) { } } }
51. Namespaces module { module("B") { factory { ComponentA() } factory { ComponentB(get()) } } module(“C") { factory { ComponentA() } factory { ComponentB(get()) } } } class ComponentB(c : ComponentA) class ComponentC(c : ComponentA)
52. Namespaces module { module("B") { factory { ComponentA() } factory { ComponentB(get()) } } module(“C") { factory { ComponentA() } factory { ComponentB(get()) } } } class ComponentB(c : ComponentA) class ComponentC(c : ComponentA)
53. Namespaces module { module("B") { factory { ComponentA() } factory { ComponentB(get()) } } module(“C") { factory { ComponentA() } factory { ComponentB(get()) } } } class ComponentB(c : ComponentA) class ComponentC(c : ComponentA)
54. Namespaces module { module("B") { factory { ComponentA() } factory { ComponentB(get()) } } module(“C") { factory { ComponentA() } factory { ComponentB(get()) } } } class ComponentB(c : ComponentA) class ComponentC(c : ComponentA) // B.ComponentA // B.ComponentB // C.ComponentA // C.ComponentC
55. Scopes
56. Scopes module { scope(scopeId = “scope_id”) { … } }
57. Scopes module { scope(scopeId = “scope_id”) { … } }
58. Scopes module { scope(scopeId = “scope_id”) { … } } // create a scope val session = getKoin().createScope("scope_id") // or get scope if already created before val session = getKoin().getScope("scope_id") // will return the same instance of Presenter until Scope is closed val presenter = get<Presenter>() // close the scope session.close() // instance of presenter has been dropped
59. Scopes module { scope(scopeId = “scope_id”) { … } } // create a scope val session = getKoin().createScope("scope_id") // or get scope if already created before val session = getKoin().getScope("scope_id") // will return the same instance of Presenter until Scope is closed val presenter = get<Presenter>() // close the scope session.close() // instance of presenter has been dropped
60. Scopes module { scope(scopeId = “scope_id”) { … } } // create a scope val session = getKoin().createScope("scope_id") // or get scope if already created before val session = getKoin().getScope("scope_id") // will return the same instance of Presenter until Scope is closed val presenter = get<Presenter>() // close the scope session.close() // instance of presenter has been dropped
61. Scopes module { scope(scopeId = “scope_id”) { … } } // create a scope val session = getKoin().createScope("scope_id") // or get scope if already created before val session = getKoin().getScope("scope_id") // will return the same instance of Presenter until Scope is closed val presenter = get<Presenter>() // close the scope session.close() // instance of presenter has been dropped
62. Scopes module { scope(scopeId = “scope_id”) { … } } // create a scope val session = getKoin().createScope("scope_id") // or get scope if already created before val session = getKoin().getScope("scope_id") // will return the same instance of Presenter until Scope is closed val presenter = get<Presenter>() // close the scope session.close() // instance of presenter has been dropped
63. Binding scope to lifecycle class MyActivity : AppCompatActivity() { // inject Presenter instance, tied to current “session" scope val presenter : Presenter by inject() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) // bind current lifecycle to Activity's scope bindScope(getScope("session")) }
64. Binding scope to lifecycle class MyActivity : AppCompatActivity() { // inject Presenter instance, tied to current “session" scope val presenter : Presenter by inject() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) // bind current lifecycle to Activity's scope bindScope(getScope("session")) }
65. Logging
66. class Presenter(repository: Repository) class Repository(dateSource: DateSource) interface DateSource class DebugDataSource() : DateSource
67. module { factory { Presenter(get()) } single { Repository(get()) } single<DateSource> { DebugDataSource() } } class Presenter(repository: Repository) class Repository(dateSource: DateSource) interface DateSource class DebugDataSource() : DateSource
68. module { factory { Presenter(get()) } single { Repository(get()) } single<DateSource> { DebugDataSource() } } get<Presenter>() get<Presenter>() class Presenter(repository: Repository) class Repository(dateSource: DateSource) interface DateSource class DebugDataSource() : DateSource
69. module { factory { Presenter(get()) } single { Repository(get()) } single<DateSource> { DebugDataSource() } } get<Presenter>() get<Presenter>() (KOIN)::Resolve [Presenter] ~ Factory[class=Presenter] (KOIN):: Resolve [Repository] ~ Single[class=Repository] (KOIN):: Resolve [Datasource] ~ Single[class=DebugDatasource, binds~(Datasource)] (KOIN):: (*) Created (KOIN):: (*) Created (KOIN)::(*) Created (KOIN)::Resolve [Repository] ~ Factory[class=Repository] (KOIN):: Resolve [DebugDatasource] ~ Single[class=DebugDatasource, binds~(Datasource)] (KOIN)::(*) Created class Presenter(repository: Repository) class Repository(dateSource: DateSource) interface DateSource class DebugDataSource() : DateSource
70. Missing dependency module { single { ComponentA(get()) } single { ComponentB(get()) } } class ComponentA(component: ComponentB) class ComponentB(component: ComponentA) get<ComponentC>()
71. Missing dependency module { single { ComponentA(get()) } single { ComponentB(get()) } } class ComponentA(component: ComponentB) class ComponentB(component: ComponentA) org.koin.error.DependencyResolutionException: No definition found for ComponentC - Check your definitions and contexts visibility get<ComponentC>()
72. Cyclic dependencies class ComponentA(component: ComponentB) class ComponentB(component: ComponentA)
73. Cyclic dependencies module { single { ComponentA(get()) } single { ComponentB(get()) } } class ComponentA(component: ComponentB) class ComponentB(component: ComponentA)
74. Cyclic dependencies get<ComponentA>() module { single { ComponentA(get()) } single { ComponentB(get()) } } class ComponentA(component: ComponentB) class ComponentB(component: ComponentA)
75. Cyclic dependencies org.koin.error.BeanInstanceCreationException: Can't create bean Bean[class=ComponentA] due to error : BeanInstanceCreationException: Can't create bean Bean[class=ComponentB] due to error : BeanInstanceCreationException: Can't create bean Bean[class=ComponentA] due to error : DependencyResolutionException: Cyclic dependency detected while resolving class ComponentA module { single { ComponentA(get()) } single { ComponentB(get()) } } class ComponentA(component: ComponentB) class ComponentB(component: ComponentA) get<ComponentA>()
76. Tests
77. Tests class SampleTest : KoinTest { val presenter : MyPresenter by inject() val repository : Repository by inject() @Before fun before(){ startKoin(listOf(myModule)) } @Test fun testSayHello() { val hello = repository.giveHello() assertEquals(hello, presenter.sayHello()) } @After fun after(){ closeKoin() } }
78. Tests class SampleTest : KoinTest { val presenter : MyPresenter by inject() val repository : Repository by inject() @Before fun before(){ startKoin(listOf(myModule)) } @Test fun testSayHello() { val hello = repository.giveHello() assertEquals(hello, presenter.sayHello()) } @After fun after(){ closeKoin() } }
79. Tests class SampleTest : KoinTest { val presenter : MyPresenter by inject() val repository : Repository by inject() @Before fun before(){ startKoin(listOf(myModule)) } @Test fun testSayHello() { val hello = repository.giveHello() assertEquals(hello, presenter.sayHello()) } @After fun after(){ closeKoin() } }
80. Tests class SampleTest : KoinTest { val presenter : MyPresenter by inject() val repository : Repository by inject() @Before fun before(){ startKoin(listOf(myModule)) } @Test fun testSayHello() { val hello = repository.giveHello() assertEquals(hello, presenter.sayHello()) } @After fun after(){ closeKoin() } }
81. Tests class SampleTest : KoinTest { val presenter : MyPresenter by inject() val repository : Repository by inject() @Before fun before(){ startKoin(listOf(myModule)) } @Test fun testSayHello() { val hello = repository.giveHello() assertEquals(hello, presenter.sayHello()) } @After fun after(){ closeKoin() } }
82. Declare on the fly class SampleTest : KoinTest { @Test fun testSayHello() { startKoin(listOf(myModule)) declare { single<Repository> { RepositoryImpl() } } val presenter : MyPresenter = get() assertEquals(hello, presenter.sayHello()) } }
83. Mock out of the box class SampleTest : KoinTest { @Test fun testSayHello() { startKoin(listOf(myModule)) declareMock<Repository>() val presenter : MyPresenter = get() assertEquals(hello, presenter.sayHello()) } }
84. Graph validation
85. Graph validation class ComponentA(component: ComponentB) class ComponentB(component: ComponentC) class ComponentC()
86. Graph validation class ComponentA(component: ComponentB) class ComponentB(component: ComponentC) class ComponentC() val sampleModule = module { single { ComponentA(get()) } factory { ComponentB(get()) } }
87. Graph validation class ComponentA(component: ComponentB) class ComponentB(component: ComponentC) class ComponentC() val sampleModule = module { single { ComponentA(get()) } factory { ComponentB(get()) } } class DryRunTest : KoinTest { @Test fun dryRunTest() { startKoin(listOf(sampleModule)) dryRun() } }
88. Android Arch Components
89. Default Way class ListFragment : Fragment() { val listViewModel = ViewModelProviders.of(this).get(ListViewModel::class.java) }
90. Simpler with Kotlin class ListFragment : Fragment() { val listViewModel = getViewModel<ListViewModel>() } inline fun <reified VM : ViewModel> Fragment.getViewModel():VM { return viewModelProvider.get(VM::class.java) }
91. ViewModel with arguments class DetailViewModel(id: String) : ViewModel()
92. ViewModel with arguments class DetailViewModel(id: String) : ViewModel() class DetailFactory(val id: String) : ViewModelProvider.Factory { override fun <T : ViewModel> create(modelClass: Class<T>): T { if (modelClass == DetailViewModel::class.java) { return DetailViewModel(id) as T } error("Can't create ViewModel for class='$modelClass'") } }
93. ViewModel with arguments class DetailViewModel(id: String) : ViewModel() class DetailFactory(val id: String) : ViewModelProvider.Factory { override fun <T : ViewModel> create(modelClass: Class<T>): T { if (modelClass == DetailViewModel::class.java) { return DetailViewModel(id) as T } error("Can't create ViewModel for class='$modelClass'") } } class DetailFragment : Fragment() { val listViewModel = getViewModel<DetailViewModel>(DetailFactory(id)) }
94. Koin Way model { viewModel { (id : String) -> DetailViewModel(id) } }
95. Koin Way model { viewModel { (id : String) -> DetailViewModel(id) } }
96. Koin Way model { viewModel { (id : String) -> DetailViewModel(id) } } class DetailFragment : Fragment() { val detailViewModel by viewModel<DetailViewModel> { parametersOf(“sampleId") } }
97. Koin vs Dagger 2
98. What missed from Dagger 2?
99. What missed from Dagger 2? • Compile time validation
100. What missed from Dagger 2? • Compile time validation • Features • Multibindings • Async Injection • Reusable scope
101. Why use Koin?
102. Why use Koin? • Dagger 2 is too complex for start with DI
103. Why use Koin? • Dagger 2 is too complex for start with DI • No need Dagger 2 advanced features
104. Why use Koin? • Dagger 2 is too complex for start with DI • No need Dagger 2 advanced features • Single place of dependencies declaration
105. Why use Koin? • Dagger 2 is too complex for start with DI • No need Dagger 2 advanced features • Single place of dependencies declaration • DSL is amazing for dependencies declaration
106. Why use Koin? • Dagger 2 is too complex for start with DI • No need Dagger 2 advanced features • Single place of dependencies declaration • DSL is amazing for dependencies declaration • Support Kotlin Multiplatform projects
107. Why use Koin? • Dagger 2 is too complex for start with DI • No need Dagger 2 advanced features • Single place of dependencies declaration • DSL is amazing for dependencies declaration • Support Kotlin Multiplatform projects • Faster build time
108. Why use Koin? • Dagger 2 is too complex for start with DI • No need Dagger 2 advanced features • Single place of dependencies declaration • DSL is amazing for dependencies declaration • Support Kotlin Multiplatform projects • Faster build time • Pure Kotlin code
109. Thanks insert-Koin.io krl.rozov@gmail.com krlrozov