CODEWITHSUNDEEP
javanaming-conventions
user2022068
user2022068

Reputation:

Java boolean setter with "has" prefix according to naming convention

Simple question but I can't understand.

Example with is prefix:

private boolean active;

public boolean isActive(){...};//getter

public boolean setActive(boolean b){...};//setter

But I don't understand how to do setter with has prefix

private boolean hasChildren;

public boolean hasChildren(){...};//getter

public boolean  ?(boolean b){...}//setter

Upvotes: 7

Views: 7530

Answers (7)

Marco13
Marco13

Reputation: 54649

The problem in your case is not only finding an appropriate name for the setter. It is also that your getter does not follow the conventions!

The specification and the tutorial are very clear on this:

  • The setter for a property should be prefixed with set
  • The getter for a non-boolean property should be prefixed with get
  • The getter for a boolean property should be prefixed with is

And it is important to follow these conventions, because otherwise, many automatic (reflection-based) tools will no longer work as expected (e.g. Introspectors).

Grammar aside, there are several options for solving this. In a comment, it was suggested to call the property isParent, although then, strictly speaking, the accessor would have to be called isIsParent...

So I'd suggest to simply call the property something like havingChildren or owningChildren, and offer the corresponding accessor methods like isHavingChildren/setHavingChildren, or isOwningChildren/setOwningChildren, respectively.

Upvotes: 12

h7r
h7r

Reputation: 5074

According to the JavaBeans Specification (section 8.3.2) accessor methods for a boolean field foo are isFoo() and setFoo(boolean) accordingly.

Your case would be a accessor pair isHasChildren()/setHasChildren().

As a suggestion, your should consider renaming of the field into boolean childrenPresent;, which would, according to the spec, be derived into isChildrenPresent() and setChildrenPresent().

Upvotes: 3

Dici
Dici

Reputation: 25960

You can safely go for setHasChildren as it is totally clear. Nevertheless if you are storing more information about the children, it could change the answer.

For example, if you need to store the children, only the setter would make sense and the children would be represented by a collection :

// no hasChildren attribute
private Collection<ChildClass> children;
public boolean hasChildren(){ return !children.isEmpty(); };
// no setter

Another example, if you are storing the number of children :

// no hasChildren attribute
private int childrenCount;
public boolean hasChildren(){ return childrenCount > 0 };
// no setter

Upvotes: 0

T.J. Crowder
T.J. Crowder

Reputation: 1074485

If it's really as in your code, where you have a boolean for this, go ahead and use setHasChildren.

Usually, "has" sorts of attributes don't have simple setters because they're usually reporting a state that isn't backed by a simple boolean, e.g.:

private List<Child> children;
// ...
public boolean hasChildren() {
    return children.size() > 0;
}
// ...
public void addChild(Child c) {
    // ...
}

But when that's not the case, setHasXyz is fine.

Upvotes: 0

Jeff Watkins
Jeff Watkins

Reputation: 6359

hasChildren is inspecting the state of an object and as such I wouldn't usually expect a setter method.

I would expect that if you had no children (hasChildren() == false) and then were to addChild(Whatever) then the next time you call hasChildren, it would return true.

By attempting to manipulate that behaviour manually, you're breaking encapsulation and the Law of Demeter as your calling program should know about its owned objects, but not the implementation of its objects own objects. I hope that makes some sense.

To make a crude analogy, you could ask a lady if she's with child and she will (hopefully) report her status (or start crying because you just called her "large). If false, you could proceed to make her pregnant (subject to consent of course), you wouldn't just cram a baby up there and say "there, you're pregnant now".

Upvotes: 0

Neeraj Jain
Neeraj Jain

Reputation: 7730

For Boolean you can use is as a prefix in getter , or you can also use get as a prefix 

public boolean isHasChildern();//getter
public boolean getHasChilder();//getter
public boolean setHasChildren(boolean active);//setter

Upvotes: 0

SamDJava
SamDJava

Reputation: 267

When we are talking about hasChildren , hasAttributes , we are talking about whether there is any collections attached to it. Like children can be many , eg can be a list or a map whereas incase of isActive we are just denoting a single property value. You can set the value setHasChildren. But then I think naming convention is for convenience of understanding.

Upvotes: -1

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