kotlin - Spotbug是否与Kotlin兼容？

Question

在Kolin项目上运行Spotbug时，出现如下错误:

[ERROR] Private method com.example.CSVRecord.component1() is never called [com.example.CSVRecord] In CSVRecord.kt UPM_UNCALLED_PRIVATE_METHOD

在以下类(class)上:

data class CSVRecord(private val columns: SortedSet<CSVColumn>) : Iterable<String> {

    override fun iterator(): Iterator<String> {
        return columns.map { it.value }.iterator()
    }
}

我不清楚 component1的来源!

Answer 1

根据Data Classes文档:

The compiler automatically derives the following members from all properties declared in the primary constructor:

• equals()/hashCode() pair;
• toString() of the form "User(name=John, age=42)";
• componentN() functions corresponding to the properties in their order of declaration;
• copy() function (see below).

这是数据类的功能之一。自动生成的 componentN函数允许您在以下类型的类上使用 Destructuring Declarations:

data class Result(val result: Int, val status: Status)
fun function(...): Result {
    // computations

    return Result(result, status)
}

// Now, to use this function:
val (result, status) = function(...)