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homework
Share your code with user fmcarvalho in a private Github repository named isel-lae-2122-your_number.
Implement the Point.java (equivalent to Point.kt) and use it in an App.kt program.
Consider the following definition of Point class and its client application App, both in Kotlin. Build, run AppKt.class and check its output.
Then, without changing any code of App.kt, replace the Point.kt with a new equivalent implementation of Point.java in Java, which maintains the same output when running AppKt.class.
data class Point(val x: Int, val y: Int) {
fun distance(other: Point = Point(0,0)) : Double {
val dX = x - other.x
val dY = y - other.y
return sqrt((dX*dX + dY*dY).toDouble())
}
} |
fun main() {
val p1 = Point(5, 7)
val p2 = Point(3, 9)
println("Distance $p1 to $p2 = ${p1.distance(p2)}")
println("Distance $p1 to (0,0) = ${p1.distance()}")
} |
Implement a fun inspectKlass(klass: KClass<*>) that prints the qualified name of klass
followed by its properties and member functions.
-
For each function it should print its return type and parameters.
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For each parameterless function it should present its invocation result through
call(). For functions requiring a target instance (i.e.this) you should create an object withcreateInstance()ofKClassand pass it tocall().
Implement logFunctions(target: Any) of Logger of lesson 6, to print the result
of parameterless functions calls on target.
Notice, you should only call functions that are declared in the target class
(i.e. not inherited) and without void (i.e. Unit) result.
Your implementation should pass the unit test
testLogAccountPropertiesAndFunctions(). Notice that for class SavingsAccount
of unit tests, the logger output should include the result of the function call monthlyInterest(), and also balance and annualInterestRate
properties, whose getters are also functions.
Complete the implementation of buildGetterProperty(klass: KClass<*>, prop: KProperty<*>) that satisfies the unit test DynamicLoggerTest.kt:
@Test fun testDynamicGetter() {
val bal: KProperty<*> = SavingsAccount::class
.declaredMemberProperties
.find { it.name == "balance" }
?: throw Exception("SavingsAccount without a property balance!!!")
val getterBalanceKlassFile = buildGetterProperty(SavingsAccount::class, bal)
val out = PrinterStringBuffer()
val getterBalance = loadAndCreateInstance(getterBalanceKlassFile, out) as Getter
getterBalance.readAndPrint(SavingsAccount(2733, 2.5))
assertEquals("balance = 2733,", out.buffer.toString())
}public void readAndPrint(java.lang.Object);
Code:
aload_1
checkcast #3 // class pt/isel/SavingsAccount
invokevirtual #4 // Method pt/isel/SavingsAccount.getBalance:()J
invokestatic #5 // Method java/lang/Long.valueOf:(J)Ljava/lang/Long;
astore_2
aload_0
getfield #2 // Field out:Lpt/isel/Printer;
aload_2
invokedynamic #6, 0 // InvokeDynamic #0:makeConcatWithConstants:(Ljava/lang/Object;)Ljava/lang/String;
invokeinterface #7, 2 // InterfaceMethod pt/isel/Printer.print:(Ljava/lang/Object;)V
return
Given the eager implementation of concat(), implement a new extension
function:
-
concatLazy()that returns a lazy implementation ofIterable<T> -
concat()that returns a lazy implementation ofSequence<T>taking advantage of the auxiliary kotlin functionsequence
Example of a unit test using concat
/**
* Eager implementation of concat for Iterable sequences.
*/
fun <T> Iterable<T>.concat(other: Iterable<T>): Iterable<T> {
val res = mutableListOf<T>()
for (item in this) { res.add(item) }
for (item in other) { res.add(item) }
return res
}