Subject: Var access question... 2006-11-01 - By Tim Wood
Back
I'll probably get flak for this BUT... :)
Defining and using getters for private state just adds needless indirection and
makes the resulting Java even more function-call intensive. I still like the
naming convention approach:
public class ComplexNumber {
private double m_real;
private double m_imaginary;
...
public double magnitude() {
return (Math.sqrt(Math.pow(m_real, 2)
+ Math.pow(m_imaginary, 2)));
}
...
}
This clearly distinguishes members from locals, and lets method code work
concisely with private data. Tools like checkstyle can enforce the convention.
I agree having member names look like local names can be confusing. In the
event that the method body needs to be moved away from the state it touches,
accessors will be needed. The naming convention makes it easy to safely change
the references to accessors, if you don't have an IDE to do the refactoring for
you.
HTH,
TW
At 10:43 AM 11/01/06, Karr, David wrote:
>I often implement private getters for properties that should only be
>accessed from within the class. I like to keep local variables and
>instance variables semantically apart, to emphasize that instance
>variables should only be declared if they're really necessary.
>
>> -- --Original Message-- --
>> From: A mailing list for Java(tm) 2 Platform, Enterprise
>> Edition [mailto:J2EE-INTEREST@(protected)] On Behalf Of Ne'Bahn
>> Sent: Tuesday, October 31, 2006 4:59 AM
>> To: J2EE-INTEREST@(protected)
>> Subject: Var access question...
>>
>> Hi list, I'm wondering if it's a good practice to access
>> fields (in the same class) through its names and not by its
>> accessors, e.g.
>>
>> public class ComplexNumber {
>> private double U;
>> private double V;
>>
>> // constructor deleted
>>
>> public double real() {
>> return U;
>> }
>>
>> public double imaginary() {
>> return V;
>> }
>>
>> public double magnitude() {
>> return (Math.sqrt(Math.pow(U, 2) + Math.pow(V, 2)));
>> // access here must be U or real(), same with V }
>>
>> public double arg() throws ArithmeticException {
>> return (Math.atan(V / U));
>> // access here must be U or real(), same with V }
>>
>> public ComplexNumber times(ComplexNumber Z) {
>> return new ComplexNumber(U * Z.U - V * Z.V, U * Z.V + V * Z.U); } }
>>
>> I think it accomplish to OOP rules (encapsulation), the
>> object itself manages its state interacting with its fields
>> and no other can change their properties, but I've seen many
>> samples that use getters methods to access values, I don't
>> know why...any clue ??? ...
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