scala - 无法覆盖 java.lang.String 字段。怎么了？

Question

我试图编译包含的代码

class FixedIndexedRepository(override val name: java.lang.String, location: URI) extends FixedIndexedRepo

其中扩展 FixedIndexedRepo它扩展了 Java 类 AbstractIndexedRepo

public abstract class AbstractIndexedRepo implements RegistryPlugin, Plugin, RemoteRepositoryPlugin, IndexProvider, Repository {
...
protected String name = this.getClass().getName();
...

不幸的是，Scala 2.9.2 编译器因错误而停止:

.../FixedIndexedRepository.scala:29: overriding variable name in class AbstractIndexedRepo of type java.lang.String;
[error]  value name has incompatible type
[error] class FixedIndexedRepository(override val name: java.lang.String, location: URI) extends FixedIndexedRepo

如何解决这个问题？怎么了？

Answer 1

雷克斯说它很丑:

Making a public accessor from an inherited protected Java field

鉴于:

package j;

public class HasName {
    protected String name = "name";
}

那么假冒是:

package user

private[user] class HasNameAdapter extends j.HasName {
  protected def named: String = name
  protected def named_=(s: String) { name = s }
}

class User(n: String = "nom") extends HasNameAdapter {
  def name(): String = named
  def name_=(s: String) { this named_= s }
  this name_= n
}

object Test extends App {
  val u = new User("bob")
  Console println s"user ${u.name()}"
  Console println s"user ${u.name}"
}

你被预先警告过丑陋。

我也没有完全弄清楚细节，但周末快到了。

Unfortunately Scala 2.9.2 compiler stops with an error

您的意思是，幸运的是它因错误而停止。