可以简化此Kotlin转换代码吗?

时间:2019-05-29 18:46:03

标签: generics kotlin

我们有一些返回第三方SDK的代码,该代码返回“是否?”。而且我们必须强制转换(如果它强制转换并解析)。由于我们的类型转换是通用的,因此如果不编写5个类型转换,我将无法弄清楚如何简化此转换。在Swift中,这似乎容易得多。有没有更好的方法来进行这些投射?

private fun parseOrganizations(payload: Any?): List<UserOrganization> {
        val organizations = mutableListOf<UserOrganization>()
        payload?.let { userData ->
            if (userData is Map<*, *>) {
                val orgJsonList = userData["organizations"]
                if (orgJsonList is List<*>) {
                    for (jsonMap in orgJsonList) {
                        if (jsonMap is Map<*, *>) {
                            val id = jsonMap["id"] as? String
                            val name = jsonMap["name"] as? String
                            val role = jsonMap["role"] as? String
                            val isActive = jsonMap["isActive"] as? Boolean
                            val isVerified = jsonMap["isVerified"] as? Boolean
                            if (id != null && name != null && role != null && isActive != null && isVerified != null) {
                                val org = UserOrganization(id, name, role, isActive, isVerified)
                                organizations.add(org)
                            }
                        }
                    }
                }
            }
        }
        return organizations
    }

谢谢大家。

1 个答案:

答案 0 :(得分:2)

您可以避免很多嵌套的if,只需将其更改为?.let并将for更改为map即可。在这种情况下,代码将是平坦且可读的

fun parseOrganizations(payload: Any?) {
    payload
        ?.let { it as? Map<*, *> }
        ?.let { it["organizations"] as? List<*> }
        ?.mapNotNull { if (it is Map<*, *>) UserOrganization.fromMap(it) else null }
        ?.map { organizations.add(it) }
}

但是我们应该处理从UserOrganization开始创建包含组织详细信息的Map。老实说,我想不出一个真正优雅的方法。但是最好创建外部函数或类似的东西来封装回退逻辑:

class UserOrganization(
    val id: String,
    val name: String,
    val role: String,
    val isActive: Boolean,
    val isVerified: Boolean
){
    companion object {
        fun fromMap(org: Map<*,*>): UserOrganization? =
            if (org.keys.containsAll(listOf("id", "name", "role", "isActive", "isVerified"))) {
                UserOrganization(
                    id = org["id"] as? String ?: "Unknown Id",
                    name = org["name"] as? String ?: "Unknown name",
                    role = org["role"] as? String ?: "Unknown role",
                    isActive = org["isActive"] as? Boolean ?: false,
                    isVerified = org["isVerified"] as? Boolean ?: false
                )
            } else null
    }
}

我不能打赌它可以100%正确地工作,但是我想我可以证明这个想法。