Clever way for a method to accept any combination of unique objects as parameters?

Question

I have a class that can be constructed with a String , Record , and Criteria . Is there any way to allow the method signature to accept these parameters in any order (other than creating multiple constructors)? This is more of an academic question than anything.

Answer 1

No, the language specification mentions no such easy way.

You can always pass Object s and perform type checks yourself, but that's a wrong approach.

Java does not allow named parameters (ways around it in link) .

Answer 2

一种选择是创建一个保存并表示这三个参数的类，但是我只建议如果这三个参数以某种方式相关联，从而在对象模型中具有逻辑意义。

Answer 3

You can do something like this :

public class MyClass ()
{

  private String _str;
  private Record _rec;
  private Criteria _crit;

  public MyClass ()
  {
    _rec = null;
    _crit = null;
    _str = null;
  }

  public MyClass string (String str)
  {
    this._str = str;
    return this;
  }

  public MyClass record (Record rec)
  {
    this._rec = rec;
    return this;
  }

  public MyClass criteria (Criteria crit)
  {
    this._crit = crit;
    return this;
  }

  public static void getInstance ()
  {
    return new MyClass ();
  }

  public static void main (String[] args)
  {
     MyClass instance = MyClass.getInstance ().string("something").criteria(someCriteria).record(someRecord);
  }
}