Reference a Non-static interface in a static Method

[JiaPei Jen]

I have a bean class, which accesses a data access object interface and the concrete class that implements that interface; therefore, I have a statement like:

EditorDAO ed = new MySQLEditorDAO();

There is a static method in this bean class. I got a compilation saying that the instance with the type of the data access object interface cannot be referenced from a static context:

EditorBean.java:42: non-static variable ed cannot be referenced from a static context
return ed.findEditor( username );

What should I do?

public class EditorBean {
   private String username;
   private String userrole;
   private String category;
   EditorDAO ed = new MySQLEditorDAO();
   public EditorBean() {}
   public EditorBean( String username, String userrole, String category )
   {
      setUsername( username );
      setUserrole( userrole );
      setCategory( category );
   }
   public String getUsername() {
      return username;
   }
   public void setUsername( String username ) {
      this.username = username;
   }
   public String getUserrole() {
      return userrole;
   }
   public void setUserrole( String userrole ) {
      this.userrole = userrole;
   }
   public String getcategory() {
      return category;
   }
   public void setCategory( String category ) {
      this.category = category;
   }
   public static EditorBean findEditorData( String username, EditorBean editorData ) 
   {
      return ed.findEditor( username );
   } 
}

[Jamie Robertson]

Your 2 choices are to
1. Make the method non-static ( instance )
2. Make the EditorDAO attribute static
depends on which one makes sense.
Otherwise, say you have

EditorBean b1 = new EditorBean(  );
EditorBean b2 = new EditorBean(  );
EditorBean.findEditorData( "Jim", b1 );  //using b2 would not change anything

now which ed object is the findEditor( username ); going to be called from? the one from b1 or the one from b2? that's why the java compiler is complaining.
Jamie

[Jamie Robertson]

but on further inspection, I wondered why you passed an EditorBean into the findEditorData() method when you don't ever use it. So I think that you may want to reference the parameter EditorBean's ed object. You just have to change your code to say that you want to use the ed object from the EditorBean parameter:

public static EditorBean findEditorData( String username, EditorBean [B]editorData[/B] )
{
      return [B]editorData[/B].ed.findEditor( username );
}

Now the compiler knows which ed object you want to call the findEditor method on.
Jamie
[ November 28, 2003: Message edited by: Jamie Robertson ]

[JiaPei Jen]

Thanks for your reply. I deleted the second parameter in the findEditorData(); But, I am still not out of the woods. Now, please help me with my conceptual problem:
1. I got "non-static variable ed cannot be referenced from a static context"

when my code is

    public static EditorBean findEditorData( String username ) 
   {
      return ed.findEditor( username );
   } 
   

The error message was the same after I changed to

      return EditorBean.ed.findEditor( username );
   

2. I then made findEditorData( String username ) non-static

   public EditorBean findEditorData( String username ) 
   {
      return ed.findEditor( username );
   } 
   

I got this compilation error:

       HttpSession session = request.getSession();
       session.setAttribute( "editor", editor );

[ November 28, 2003: Message edited by: JiaPei Jen ]