我有一個很大的 Kotlin 物件，需要對特定屬性做一些操作。這是一個演示的小例子：
class ObjectForAnalysis {
var id: Int = 0
lateinit var successful: SUCCESSFUL
var job1: Job? = null
var job2: Job? = null
var job3: Job? = null
}
想象一下，我有上述物件的多個實體，并且需要對 Job 型別的屬性進行以下操作。
job !=null && job.computeSquare() < 1000
我怎么能做到這一點？
uj5u.com熱心網友回復：
import kotlin.reflect.full.memberProperties
class Job(private var i: Int) {
fun getI(): Int = i
}
class ObjectForAnalysis {
var id: Int = 0
var job1: Job? = null
var job2: Job? = null
var job3: Job? = null
}
val list = listOf(
ObjectForAnalysis().also { it.id = 1; it.job1 = Job(2) },
ObjectForAnalysis().also { it.id = 2; it.job1 = Job(4); it.job2 = Job(3); it.job3 = Job(9) },
ObjectForAnalysis().also { it.id = 3; it.job1 = Job(12); it.job2 = Job(15) },
ObjectForAnalysis().also { it.id = 4 },
)
val properties = ObjectForAnalysis::class.memberProperties.filter { it.name.startsWith("job") }
val result = list
.filter { ofa ->
properties
.map { kProperty1 ->
(kProperty1.get(ofa) as Job?)?.let { job: Job -> job.getI() < 10 }
}
.all { it != null && it == true } // all i need to be < 10
// .any { it != null && it == true } // at least one i needs to be < 10
}
println("result:")
result.forEach {
println("id: ${it.id}, ints: ${it.job1?.getI()}, ${it.job2?.getI()}, ${it.job3?.getI()}")
}
println("excluded:")
list.minus(result).forEach {
println("id: ${it.id}, ints: ${it.job1?.getI()}, ${it.job2?.getI()}, ${it.job3?.getI()}")
}
.all { it!= null && it == true }的輸出：
result:
id: 2, ints: 4, 3, 9
excluded:
id: 1, ints: 2, null, null
id: 3, ints: 12, 15, null
id: 4, ints: null, null, null
.any { it != null && it == true }的輸出：
result:
id: 1, ints: 2, null, null
id: 2, ints: 4, 3, 9
excluded:
id: 3, ints: 12, 15, null
id: 4, ints: null, null, null
轉載請註明出處，本文鏈接：https://www.uj5u.com/qianduan/440832.html