Все делаю и планирую делать на примере юридических вопросов

src/main/kotlin/ru/otus/homework/Builder.kt

@@ -0,0 +1,91 @@
+package ru.otus.homework
+
+//Строитель
+
+interface CaseBuilder {
+    fun setClientName(clientName: String): CaseBuilder
+    fun setCaseType(caseType: String): CaseBuilder
+    fun setDescription(description: String): CaseBuilder
+    fun setDate(date: String): CaseBuilder
+    fun build(): LegalCase
+}
+
+data class LegalCase(
+    val clientName: String,
+    val caseType: String,
+    val description: String,
+    val date: String
+) {
+    override fun toString(): String {
+        return "Заведено $caseType от $date на $clientName по статье $description"
+    }
+}
+
+class LegalCaseBuilder : CaseBuilder {
+    private lateinit var clientName: String
+    private lateinit var caseType: String
+    private lateinit var description: String
+    private lateinit var date: String
+
+
+    override fun setClientName(clientName: String): CaseBuilder {
+        this.clientName = clientName
+        return this
+    }
+
+    override fun setCaseType(caseType: String): CaseBuilder {
+        this.caseType = caseType
+        return this
+    }
+
+    override fun setDescription(description: String): CaseBuilder {
+        this.description = description
+        return this
+    }
+
+    override fun setDate(date: String): CaseBuilder {
+        this.date = date
+        return this
+    }
+
+    override fun build(): LegalCase {
+        return LegalCase(clientName, caseType, description, date)
+    }
+}
+
+fun main() {
+    val criminalCase = LegalCaseBuilder()
+        .setClientName("Иванов Иван")
+        .setCaseType("Уголовное дело")
+        .setDescription("Кража")
+        .setDate("18.04.2023")
+        .build()
+
+    val familyCase = LegalCaseBuilder()
+        .setClientName("Петров Петр")
+        .setCaseType("Семейное дело")
+        .setDescription("Развод")
+        .setDate("25.04.2023")
+        .build()
+
+    val civilCase = LegalCaseBuilder()
+        .setClientName("Сергеев Сергей")
+        .setCaseType("Гражданское дело")
+        .setDescription("Убытки")
+        .setDate("27.04.2023")
+        .build()
+
+    val administrativeCase = LegalCaseBuilder()
+        .setClientName("Николаев Николай")
+        .setCaseType("Административное дело")
+        .setDescription("Невменяемость")
+        .setDate("30.04.2023")
+        .build()
+
+    listOf(
+        criminalCase,
+        familyCase,
+        civilCase,
+        administrativeCase
+    ).forEach { println(it) }
+}

src/main/kotlin/ru/otus/homework/Command.kt

@@ -0,0 +1,77 @@
+package ru.otus.homework
+
+//Команда
+
+interface Command {
+    fun execute()
+}
+
+class LawOrganization {
+    fun handleCriminalCase() {
+        println("Обработка уголовного дела.")
+    }
+
+    fun handleFamilyCase() {
+        println("Обработка семейного дела.")
+    }
+
+    fun handleCivilCase() {
+        println("Обработка гражданского дела.")
+    }
+
+    fun handleAdministrativeCase() {
+        println("Обработка административного дела.")
+    }
+}
+
+class CriminalCaseCommand(private val lawOrganization: LawOrganization) : Command {
+    override fun execute() {
+        lawOrganization.handleCriminalCase()
+    }
+}
+
+class FamilyCaseCommand(private val lawOrganization: LawOrganization) : Command {
+    override fun execute() {
+        lawOrganization.handleFamilyCase()
+    }
+}
+
+class CivilCaseCommand(private val lawOrganization: LawOrganization) : Command {
+    override fun execute() {
+        lawOrganization.handleCivilCase()
+    }
+}
+
+class AdministrativeCaseCommand(private val lawOrganization: LawOrganization) : Command {
+    override fun execute() {
+        lawOrganization.handleAdministrativeCase()
+    }
+}
+
+
+class CaseInvoker(var command: Command) {
+    fun executeCommand() {
+        command.execute()
+    }
+}
+
+fun main() {
+    val lawOrganization = LawOrganization()
+
+    val criminalCaseCommand = CriminalCaseCommand(lawOrganization)
+    val familyCaseCommand = FamilyCaseCommand(lawOrganization)
+    val civilCaseCommand = CivilCaseCommand(lawOrganization)
+    val administrativeCaseCommand = AdministrativeCaseCommand(lawOrganization)
+
+    val caseInvoker = CaseInvoker(criminalCaseCommand)
+    caseInvoker.executeCommand()
+
+    caseInvoker.command = familyCaseCommand
+    caseInvoker.executeCommand()
+
+    caseInvoker.command = civilCaseCommand
+    caseInvoker.executeCommand()
+
+    caseInvoker.command = administrativeCaseCommand
+    caseInvoker.executeCommand()
+}

src/main/kotlin/ru/otus/homework/Decorator.kt

@@ -0,0 +1,62 @@
+package ru.otus.homework
+
+//Декоратор
+
+interface LegalService {
+    fun handleCase()
+}
+
+class CriminalService : LegalService {
+    override fun handleCase() {
+        println("Обработка уголовного дела")
+    }
+}
+
+class FamilyService : LegalService {
+    override fun handleCase() {
+        println("Обработка семейного дела")
+    }
+}
+
+abstract class LegalServiceDecorator(private val legalService: LegalService) : LegalService {
+    override fun handleCase() {
+        legalService.handleCase()
+    }
+}
+
+class UrgentCaseDecorator(legalService: LegalService) : LegalServiceDecorator(legalService) {
+    private fun markAsUrgent() {
+        println("Дело помечено срочным")
+    }
+
+    override fun handleCase() {
+        markAsUrgent()
+        super.handleCase()
+    }
+}
+
+class ConfidentialCaseDecorator(legalService: LegalService) : LegalServiceDecorator(legalService) {
+    private fun applyConfidentiality() {
+        println("Дело обрабатывается конфиденциально")
+    }
+
+    override fun handleCase() {
+        applyConfidentiality()
+        super.handleCase()
+    }
+}
+
+fun main() {
+    val criminalService = CriminalService()
+    val urgentCriminalService = UrgentCaseDecorator(criminalService)
+    val familyService = FamilyService()
+    val confidentialFamilyService = ConfidentialCaseDecorator(familyService)
+    val urgentConfidentialFamilyService = UrgentCaseDecorator(confidentialFamilyService)
+
+    urgentCriminalService.handleCase()
+    println()
+    confidentialFamilyService.handleCase()
+    println()
+    urgentConfidentialFamilyService.handleCase()
+}
+

src/main/kotlin/ru/otus/homework/SingletonLazy.kt

@@ -0,0 +1,46 @@
+package ru.otus.homework
+
+//Одиночка
+
+class LawService private constructor() {
+
+    init {
+        println("LawService создан")
+    }
+
+    fun handleCriminalCase() {
+        println("Обработка уголовного дела")
+    }
+
+    fun handleFamilyCase() {
+        println("Обработка семейного дела")
+    }
+
+    fun handleCivilCase() {
+        println("Обработка гражданского дела")
+    }
+
+    fun handleAdministrativeCase() {
+        println("Обработка административного дела")
+    }
+
+    companion object {
+        val instance: LawService by lazy(LazyThreadSafetyMode.SYNCHRONIZED) { LawService() }
+    }
+}
+
+fun main() {
+    val lawService1 = LawService.instance
+    lawService1.handleCriminalCase()
+    lawService1.handleFamilyCase()
+    lawService1.handleCivilCase()
+    lawService1.handleAdministrativeCase()
+
+    val lawService2 = LawService.instance
+    lawService2.handleCriminalCase()
+    lawService2.handleFamilyCase()
+    lawService2.handleCivilCase()
+    lawService2.handleAdministrativeCase()
+
+    println(lawService1 === lawService2)
+}