Deepcopy: Difference between revisions
Added Kotlin
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cp = deepcopy(obj)</lang>
=={{header|Kotlin}}==
The JDK has an Object.clone() method but it only produces a 'shallow' copy.
If a 'deep' copy is needed, then usually a custom method would be written.
However, an easy way to produce a deep copy for any object, including one which contains cyclic or null references, is to serialize it to memory and then deserialize it back to a new object. A drawback is that the class of the object to be serialized needs to be marked as implementing the Serializable interface (albeit it contains no members).
The serialization approach is used below.
<lang scala>// Version 1.2.31
import java.io.Serializable
import java.io.ByteArrayOutputStream
import java.io.ByteArrayInputStream
import java.io.ObjectOutputStream
import java.io.ObjectInputStream
fun <T : Serializable> deepCopy(obj: T?): T? {
if (obj == null) return null
val baos = ByteArrayOutputStream()
val oos = ObjectOutputStream(baos)
oos.writeObject(obj)
oos.close()
val bais = ByteArrayInputStream(baos.toByteArray())
val ois = ObjectInputStream(bais)
@Suppress("unchecked_cast")
return ois.readObject() as T
}
class Person(
val name: String,
var age: Int,
val sex: Char,
var income: Double,
var partner: Person?
) : Serializable
fun printDetails(p1: Person, p2: Person?, p3: Person, p4: Person?) {
with (p3) {
println("Name : $name")
println("Age : $age")
println("Sex : $sex")
println("Income : $income")
if (p4 == null) {
println("Partner : None")
}
else {
println("Partner :-")
with (p4) {
println(" Name : $name")
println(" Age : $age")
println(" Sex : $sex")
println(" Income : $income")
}
}
println("\nSame person as original '$name' == ${p1 === p3}")
if (p4 != null) {
println("Same person as original '${p2!!.name}' == ${p2 === p4}")
}
}
println()
}
fun main(args: Array<String>) {
var p1 = Person("John", 35, 'M', 50000.0, null)
val p2 = Person("Jane", 32, 'F', 25000.0, p1)
p1.partner = p2
var p3 = deepCopy(p1)
val p4 = p3!!.partner
printDetails(p1, p2, p3, p4)
println("..or, say, after 2 years have elpased:-\n")
with (p1) {
age = 37
income = 55000.0
partner = null
}
p3 = deepCopy(p1)
printDetails(p1, null, p3!!, null)
}</lang>
{{out}}
<pre>
Name : John
Age : 35
Sex : M
Income : 50000.0
Partner :-
Name : Jane
Age : 32
Sex : F
Income : 25000.0
Same person as original 'John' == false
Same person as original 'Jane' == false
..or, say, after 2 years have elpased:-
Name : John
Age : 37
Sex : M
Income : 55000.0
Partner : None
Same person as original 'John' == false
</pre>
=={{header|Lasso}}==
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