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Java Java Data Structures Getting There Class Review

Posted by Imuse Ekpen-Itamah
Imuse Ekpen-Itamah
5,390 Points

Instead of not creating a setter to make the member variables immutable. Why can't you just declare it final

example:

instead of: private String mAuthor;

why not: private final String mAuthor;

1 Answer

Gustáv Szilárdy
Gustáv Szilárdy
3,949 Points
Gustáv Szilárdy
Gustáv Szilárdy
3,949 Points

private String mAuthor; Using the setter you can set mAuthor many times in your code.

private final String mAuthor;

  • You have to initialize mAuthor: right in the class or in the default constructor.
  • In another code can not be changed.
// RIGHT IN THE CLASS
public class Treet {
  private final String mAuthor = "Dan Millman";

  public void setAuthor(String author) { //Error: cannot assign a value to final variable mAuthor
       mAuthor = author;
  }

}

// IN THE DEFAULT CONSTRUCTOR
public class Treet {
  private final String mAuthor;

  Treet(String author) {
     mAuthor = author;
  }

  public void setAuthor(String author) { //Error: cannot assign a value to final variable mAuthor
       mAuthor = author;
  }

}