HW-2 patterns

src/main/kotlin/bulder.kt

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+class Human(var name: String = "John", var lastName: String = "Dow", var age: Int = 18)
+
+// Если использовать билдер как конфиг объекта с дефолт значениями - то вариант более удобный

src/main/kotlin/command.kt

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+interface Calculate {
+    var result: Number
+    fun exec()
+}
+
+class Sum(var num1: Int, var num2: Int): Calculate {
+    override var result: Number = 0
+
+    override fun exec() {
+        result = num1 + num2
+    }
+}
+
+class Multiply(var num1: Double, var num2: Double): Calculate {
+    override var result: Number = 0
+
+    override fun exec() {
+        result = num1 * num2
+    }
+}
+
+class CalculatorInvoker {
+    private var lock = Any()
+    private var queue = mutableListOf<Calculate>()
+
+    fun calculate(procedure: Calculate) {
+        queue.add(procedure)
+        if (queue.size >= 9) {
+            synchronized(lock) {
+                exec()
+            }
+        }
+    }
+    private fun exec() {
+        queue.forEach {it.exec()}
+        queue.clear()
+    }
+}
+
+class Worker() {
+    var invoker = CalculatorInvoker()
+    var sum = Sum(1, 7)
+    var multiply = Multiply(1.0, 9.0)
+
+    fun start() {
+        invoker.calculate(sum)
+        invoker.calculate(multiply)
+    }
+}

src/main/kotlin/decorator.kt

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+import java.util.WeakHashMap
+
+interface Calculator {
+    fun sum(i: Int, j: Int): Int
+}
+
+class BaseCalculator : Calculator {
+    override fun sum(i: Int, j: Int): Int {
+        return i + j
+    }
+}
+
+class FastCalculator(private var calculator: Calculator): Calculator {
+    override fun sum(i: Int, j: Int): Int {
+        System.out.println("sum is ${i + j}") // logging for example. Hard to create smthng unique as example (
+        return calculator.sum(i, j)
+    }
+
+}

src/main/kotlin/main.kt

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+fun main() {
+    // singleton with lazy init
+    val singleton by lazy {
+        object {
+            val singletonVariable = 10
+        }
+    }
+}