K&B Chapter 1 Question 5

[B Bhalla]

5. Which method names follow the JavaBeans standard? (Choose all that apply.)
A. addSize
B. getCust
C. deleteRep
D. isColorado
E. putDimensions

I thought A, B and D are correct. However they say only B and D are correct.

The chapter clearly says:- JavaBeans methods must be named using camelCase, and depending on the method's purpose, must start with set, get, is, add, or remove.

What am I missing? Why is "add" not a correct answer here?

[Ryan Beckett]

add and remove are for listeners; get, set, and is are for instance variables

[B Bhalla]

Ryan Beckett wrote:add and remove are for listeners; get, set, and is are for instance variables

Thanks and agreed. But where does it mention "instance variables" in the question? All it is asking is valid method names based on JavaBeans Standard.

[Himalay Majumdar]

isn't it add and remove are just for Listeners

[Ryan Beckett]

   public class Customer 
{
	private String user;
	private String pass;
	
	public Customer(){}
	public String getUser()
	{
		return this.user;
	}
	public void setUser(String user)
	{
		this.user = user;
	}
	public String getPass()
	{
		return this.pass;
	}
	public void setPass(String pass)
	{
		this.pass = pass;
	}
} 

User and Pass are instance variables.

[B Bhalla]

Ryan Beckett wrote:

   public class Customer 
{
	private String user;
	private String pass;
	
	public Customer(){}
	public String getUser()
	{
		return this.user;
	}
	public void setUser(String user)
	{
		this.user = user;
	}
	public String getPass()
	{
		return this.pass;
	}
	public void setPass(String pass)
	{
		this.pass = pass;
	}
} 

User and Pass are instance variables.

Thanks. But I am really not clear of the point that you are trying to make. Where does the question mention "instance variable"?

Again. I really appriciate all the feedback and help here..

[Ryan Beckett]

Im talking about the naming conventions. Basically the beans are done in a standard way.

 class myBean { String name; String getName(){ return this.name; } }   

K & B are saying that this is the proper way to do it. There's nothing left to misunderstand.
If you want to know more about instance variables I'd suggest you sift through chapter 1.

I said instance variable because you must know the name of it when you create your function.
Since my instance variable's name is 'name' my method has to be 'getName'. Not 'getname',
'Getname', or 'GetName'.

Edit:

I just remembered its referred to as a 'property'. Sorry for the confusion.

[B Bhalla]

I am not sure why I am having such a great difficulty in explaining my question. Let me try to rephrase it...

The question asked in the book is as follows. I do not see any mention of the word "Instance Variable" (or Listener) in this question. So, why and how should I assume that the author of the question wants me to identify standard naming convention for a "Instance Variable" method? Why should I not say that addSize is a correct answer, assuming that Size is my Listener's name (however add it might sound!!).

5. Which method names follow the JavaBeans standard? (Choose all that apply.)
A. addSize
B. getCust
C. deleteRep
D. isColorado
E. putDimensions

[Himalay Majumdar]

whenever you use add or remove as method name..it should have Listener word associated.

[Bert Bates]

Hey B,

You probably have a slightly older version of the book. We added a couple of sentences of clarification in the newest printing. In a nutshell, the only time that "add" is a valid JavaBean prefix is when it is used with a Listener.

hth,

Bert

[B Bhalla]

Thanks Bert and Himalay. Both of you clarified my doubts.

Thanks to others who answered too. I am clear about this now.

Starting chapter 2 now.. Hope to finish it off by Tuesday or Wednesday. Will be back with more questions!