Is it bad practice to have my getter method change

Question

Is it bad practice to change my getter method like version 2 in my class.

Version 1:

 public String getMyValue(){
     return this.myValue
 }

Version 2:

 public String getMyValue(){

    if(this.myValue == null || this.myValue.isEmpty()){
       this.myValue = "N/A";
    }

    return this.myValue;
 }

Answer 1

I do feel this is a bad practice unless and until you explain the reason why it is so necessary for you modify the object inside the getter method instead of doing it inside the setter method.
Do you feel this cannot be done for some reason? Could you please elaborate?

Answer 2

In my opinion, unless you are doing lazy-loading (which you are not in that case), getters should not change the value. So I would either:

Put the change in the setter

public void setMyValue(String value) {
    if(value == null || value.isEmpty()){
        this.myValue = "N/A";
    } else {
        this.myValue = value;
    }
}

Or make the getter return a default value if value not set properly:

public String getMyValue() {
    if(this.myvalue == null || this.myvalue.isEmpty()){
        return "N/A";
    }    
    return this.myValue;
}

In the case of lazy-loading, where I would say that changing your members in a getter is fine, you would do something like:

public String getMyValue() {
    if (this.myvalue == null) {
        this.myvalue = loadMyValue();
    }    
    return this.myValue;
}

Answer 3

State changes in getters should be a hanging offence. It means that client code must be careful about the order in which it accesses getters and setters and to do this it must have knowledge of the implementation. You should be able to call the getters in any order and still get the same results. A related problem occurs when the setter modifies the incoming value depending on the current state of the object.

Answer 4

A setter could modify as part of validation, but a getter should return the value and let the validation be done by the caller. If you do validate, then how should be documented.

Answer 5

No. You're doing two things here. Getting and setting.

Answer 6

You can use some value holder for this purpose. Like Optional class in guava library.