MacWire

MacWire 为给定的类生成新的实例创建代码，在 Scala 宏的帮助下通过在构造函数参数的封闭类型中使用值实现。

MacWire 可以帮助实现依赖注入模式，不必须手工编写代码。

示例代码：

class DatabaseAccess()
class SecurityFilter()
class UserFinder(databaseAccess: DatabaseAccess, securityFilter: SecurityFilter)
class UserStatusReader(userFinder: UserFinder)

trait UserModule {
    import com.softwaremill.macwire.MacwireMacros._

    lazy val theDatabaseAccess   = wire[DatabaseAccess]
    lazy val theSecurityFilter   = wire[SecurityFilter]
    lazy val theUserFinder       = wire[UserFinder]
    lazy val theUserStatusReader = wire[UserStatusReader]
}

生成的代码：

trait UserModule {
    lazy val theDatabaseAccess   = new DatabaseAccess()
    lazy val theSecurityFilter   = new SecurityFilter()
    lazy val theUserFinder       = new UserFinder(theDatabaseAccess, theSecurityFilter)
    lazy val theUserStatusReader = new UserStatusReader(theUserFinder)
}