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Thread: Creating an object through a class parameters

  1. #1
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    Question Creating an object through a class parameters

    I'm trying to figure out how to create a class through a constructor's parameters here is my code:

    public class Article {
      private String title;
      private String body;
      private ArrayList <Author> authors = new ArrayList<Author>(); // this isn't how I'm supposed to create the object
      private GregorianCalendar pubDate = new GregorianCalendar();  // this isn't how I'm supposed to create the object
      private boolean published;
      private SimpleDateFormat a = new SimpleDateFormat("yyyy-MM-dd 'at' hh:mm:ss");
     
     
      public Article(String title) {
        this.title = title;
      }
     
      public Article(String title, String body, ArrayList<Author> author, GregorianCalendar pubDate,
                       boolean published) {
        this.title = title;
        this.body = body;
        this.authors = author; //somehow I'm supposed to pass the author class to this and create an arraylist
        this.pubDate = pubDate;
       // this.pubDate.set(year, month - 1, dayOfMonth, hour, minute);
        this.published = published;
      }

    My teacher says I shouldn't instantiate in the private fields (*or this is what I think he meant). If I create a object inside the constructor, where will the field be stored? wouldn't the object disappear? Do I have to create the object in the private fields area first?


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    Super Moderator Norm's Avatar
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    Default Re: Creating an object through a class parameters

    There are two steps:
    1) define a variable that will hold a reference to an instance
    2) assign a value to that variable.

    Those two steps can be done in different places.

    If a variable is defined inside a constructor or method, it will disappear when the constructor or method exits.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Creating an object through a class parameters

    thanks, turns out he just didn't want me to create the new object in the private fields, but just create:

    private ArrayList <Author> authors;
    which (*I'm told) will be filled with data passed into the constructor.

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