java–检查null时的惯用Kotlin

在Java中,我会做这样的事情：

class Person {
private Record record;
public String name() {
record().get("name");
}
private Record record() {
if (record == null) {
refetch();
}
return record;
}
private void refetch() {
record = service.doSomething()
}
}


在Kotlin,我有这个等价的代码：

class Person(private var record: Record?) {
fun name() : String {
record().get("name");
}
private fun record() : Record {
record ?: refetch()
return record!!;
}
private fun refetch() {
record = service.doSomething()
}
}


如你所见,我正在使用!!运算符,我真的不喜欢.还有另外一种惯用的方法吗？

如果我只是遵循Java方式(if(record == null)),我会收到此错误：

Smart cast to “Record” is impossible, because “record” is a mutable
property that could have been changed by this time

解决方法:

在惯用的Kotlin中,你会使用lazy delegated property：

class Person(private val service: Service) {
private val record by lazy { service.doSomething() }
fun name() = record.get("name");
}