Java - Using Accessor and Mutator methods

Question

I am working on a homework assignment   I am confused on how it should be done   The question is      Create a class called IDCard that contains a person s name  ID number    and the name of a file containing the person s photogrpah   Write   accessor and mutator methods for each of these fields   Add the   following two overloaded constructors to the class       public IDCard   public IDCard String n  int ID  String filename       Test your program by creating different ojbects using these two   constructors and printing out their values on the console using the   accessor and mutator methods    I have re-written this so far   public class IDCard   String Name  FileName  int ID   public static void main String   args        public IDCard         this Name   getName        this FileName   getFileName        this ID   getID       public IDCard String n  int ID  String filename        public String getName         return  Jack Smith      public String getFileName         return  Jack jpg      public int getID              return 555

User · Accepted Answer

Let s go over the basics   Accessor  and  Mutator  are just fancy names fot a getter and a setter  A getter   Accessor   returns a class s variable or its value  A setter   Mutator   sets a class variable pointer or its value   So first you need to set up a class with some variables to get set   public class IDCard       private String mName      private String mFileName      private int mID       But oh no  If you instantiate this class the default values for these variables will be meaningless   B T W   instantiate  is a fancy word for doing   IDCard test   new IDCard      So - let s set up a default constructor  this is the method being called when you  instantiate  a class   public IDCard         mName           mFileName           mID   -1      But what if we do know the values we wanna give our variables  So let s make another constructor  one that takes parameters   public IDCard String name  int ID  String filename        mName   name      mID   ID      mFileName   filename      Wow - this is nice  But stupid  Because we have no way of accessing   reading  the values of our variables  So let s add a getter  and while we re at it  add a setter as well   public String getName         return mName     public void setName  String name         mName   name      Nice  Now we can access mName  Add the rest of the accessors and mutators and you re now a certified Java newbie  Good luck

User · Answer

You need to remove the static from your accessor methods - these methods need to be instance methods and access the instance variables  public class IDCard       public String name  fileName      public int id       public IDCard final String name  final String fileName  final int id            this name   name          this fileName   fileName         this id   id             public String getName             return name            You can the create an IDCard and use the accessor like this   final IDCard card   new IDCard    card getName      Each time you call new a new instance of the IDCard will be created and it will have it s own copies of the 3 variables   If you use the static keyword then those variables are common across every instance of IDCard   A couple of things to bear in mind    don t add useless comments - they add code clutter and nothing else  conform to naming conventions  use lower case of variable names - name not Name

[java] Java - Using Accessor and Mutator methods

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