getFirstNotNullResult执行函数列表,直到其中一个函数返回非null值.
如何更优雅/简洁地实现getNotNullFirstResult?
如何更优雅/简洁地实现getNotNullFirstResult?
object A { def main(args: Array[String]) { println(test()); } def test(): String = { getFirstNotNullResult(f1 _ :: f2 _ :: f3 _ :: Nil); } def getFirstNotNullResult(fs: List[() => String]): String = { fs match { case head::tail => val v = head(); if (v != null) return v; return getFirstNotNullResult(tail); case Nil => null } } // these would be some complex and slow functions; we only want to execute them if necessary; that is,if f1() returns not null,we don't want to execute f2 nor f3. def f1(): String = { null } def f2(): String = { "hello" } def f3(): String = { null } }