我正在 Scala 中尝试文件搜索器程序。
文件检查器.scala
package fileSearcher
import sun.org.mozilla.javascript.internal.ast.Yield
class FilterChecker(filter:String) {
def matches(content: String) = content contains filter
def findMatchedFiles(fileObjects: List[IOObject]) =
for(fileObject <- fileObjects
if(fileObject.isInstanceOf[FileObject])
if(matches(fileObject.name)))
yield fileObject
}
object FilterChecker{
def apply(filter: String)=new FilterChecker(filter)
}
IOObject.scala
package fileSearcher
import java.io.File
trait IOObject {
val file:File
val name= file.getName()
}
case class FileObject(file: File)extends IOObject
case class DirectoryObject(file: File)extends IOObject
文件转换器.scala
package fileSearcher
import java.io.File
object FileConverter {
def convertToIOObject(file: File){
if(file.isDirectory()) DirectoryObject(file)
else FileObject(file)
}
}
匹配器.scala
package fileSearcher
import java.io.File
class Matcher(filter:String,rootLocation:String) {
val rootIOObject=FileConverter.convertToIOObject(new File(rootLocation))
def execute()={
val matchedFiles= rootIOObject match {
case file : FileObject if FilterChecker(filter) matches file.name =>List(file) //error 1
case directory: DirectoryObject => ??? //error 2
case _ => List()
}
matchedFiles map(iOObject => iOObject.name)
}
}
上面的代码给了我2个错误。
scrutinee is incompatible with pattern type; found : fileSearcher.FileObject required: Unit
scrutinee is incompatible with pattern type; found : fileSearcher.DirectoryObject required: Unit
任何人都可以解释我做错了什么，我该如何解决？
谢谢
最佳答案
你缺少一个等号:
def convertToIOObject(file: File) = {
^
here
没有它，编译器假定该方法返回
Unit ，这就是为什么 match声明很困惑:它不能是 FileObject或 DirectoryObject如果它必须是 Unit .
关于scala - 被审查者与模式类型不兼容；找到 : package. SomeObject required: Unit，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28839590/