Scala如何做apache commons lang3驗證？

Question

與Apache Commons lang3 Validate相同的Scala方法是什么？ 即，驗證針對用戶輸入驗證，而不是通過斷言導致錯誤的條件，斷言將導致IllegalArgumentException，例如

/**
 * Returns the newly created file only if the user entered a valid path.
 * @param path input path where to store the new file
 * @param fileName name of the file to be created in directory path
 * @throws IllegalArgumentException when the input path doesn't exist.  
 */
public File createFile(File path, String fileName) {
    // make sure that the path exists before creating the file
    // TODO: is there a way to do this in Scala without the need for 3rd party libraries
    org.apache.commons.lang3.Validate.isTrue(path.exists(), "Illegal input path '" + path.getAbsolutePath() + "', it doesn't exist")
    // now it is safe to create the file ...
    File result = new File(path, fileName)
    // ...
    return result;
}

Answer 1

碰巧的是，我剛剛發現require是Scala中的選擇方法，例如

/**
 * Returns the newly created file only if the user entered a valid path.
 * @param path input path where to store the new file
 * @param fileName name of the file to be created in directory path
 * @throws IllegalArgumentException when the input path doesn't exist.  
 */
def createFile(path: File, fileName: String) : File = {
    require(path.exists, s"""Illegal input path "${path.getAbsolutePath()}", it doesn't exist""")
    // now it is safe to create the file ...
    val result = new File(path, fileName)
    // ...
    result
}