Java method naming conventions: Too many getters

Question

Why do Java method names use the "get" prefix so extensively? At least in my Java programs there are a lot of methods with names starting with the word "get". The percentage of get-methods is suspiciously high. I am starting to feel that the word "get" is losing its meaning because of inflation. It is noise in my code.

I have noticed that there is a different naming convention being used in functional/declarative programming and PL/SQL. The method name simply states what the method returns. Instead of account.getAmount() or Time.getIsoFormattedDateString(Date date) they will use account.amount() and Time.isoFormattedDateString(Date date). This makes perfect sense to me, as the name of the function describes the result of evaluating the method (assuming there are no side effects, which there shouldn't be anyway). The "get" prefix seems superfluous.

I have just started reading the book "Clean Code". It says that methods should do only one thing, and that that thing should normally be one of the following:

1. Notify some object about an event, typically passing the event as a parameter.
2. Ask a question about some object, typically with the method name forming a natural language statement, passing the object as parameter and returning a boolean.
3. Fetch something, possibly passing some lookup key or some object to be converted as parameter and always returning the desired object/value.

My question is about the third category. Are there naming conventions other than "get" for this kind of methods? What criteria do you use when choosing method names/prefixes?

Here is an example:

I have a class with two methods getDates() and getSpecialDates(). getDates() simply returns the value of a private variable (the reference to a collection of dates). This is a standard getter, as I understand it. getSpecialDates() is different; it calls getDates(), fetches a filter from another class, applies the filter and returns what is effectively a subset of getDates().

The method getSpecialDates() could be named computeSpecialDates(), findSpecialDates(), selectSpecialDates() or elicitSpecialDates() or whatever. Or I could simply name it specialDates(). And then, for consistency, I could rename getDates() into dates().

Why bother separating between methods that should be prefixed with "get" and methods that should not, and why bother finding replacement words for "get"?

Answer 1

I personally don't use getters and setters whenever it's possible (meaning : I don't use any framework who needs it, like Struts for instance).

I prefer writing immutable objects (public final fields) when possible, otherwise I just use public fields : less boiler plate code, more productivity, less side effects. The original justification for get/set is encapsulation (make your objects as shy as possible), but in fact, I don't need it very often.

In Effective Java, Joshua Bloch makes this compelling recommendation :

Classes should be immutable unless there's a very good reason to make them mutable... If a class cannot be made immutable, limit its mutability as much as possible.

In the same book, he also says (but I don't want to copy the whole book here) :

The JavaBeans pattern has serious disadvantages.

I totally aggre with that, since JavaBeans were originally intended for a very narrow problem domain : manipulation of graphical components in an IDE. It is a bad practice to use one solution designed for solving another problem.

Answer 2

It comes from the JavaBeans naming conventions.

Answer 3

Part of the reason there's so many get* methods is that Java doesn't support "properties" a la .net/COM, and Java beans and such use functions getX and setX to replicate the functionality of a property called X. Some IDEs for Java take advantage of this to allow the setting and retrieval of properties.

Answer 4

One of the reasons that getter and setter methods are often written in Java is because of the use of JavaBeans conventions.

The standard Java API isn't consistent itself with regard to this, however. For example, class String has a length() method and interface Collection defines a size() method, instead of getLength() or getSize().

Java doesn't support the uniform access principle, so you have to write getter and setter methods to access properties.

Answer 5

Method names like getSpecialDates(), computeSpecialDates(), findSpecialDates(), selectSpecialDates() and elicitSpecialDates(), to me are commands because of the use of verbs (actions) in their names. Commands are meant to have side effects everytime you call them. Whereas method names like date(), dates(), specialDates() [nouns] are methods that return a useful value with no side effects. Calling the method multiple times returns the same value everytime, unless a command is called whose side effect is to change state.

Answer 6

One reason is that it is an essential part of the Java Bean Spec.

Answer 7

One of reasons that require Java developers to use common get/set convention is that many frameworks rely on it for bean creation and setting the fields. For example, if you have some property configured for Spring bean like <property name="foo" value="bar" /> and there's no method named setFoo() in the class, you'll get an error on bean creation.

Answer 8

Premise 1: A method should do only one thing. Premise 2: A getter method - wether it uses the get prefix or not - should have no side effects. Given these two premises I propose: A method whose role is to fetch something and that does so in a relatively simple an inexpensive manner need not have a verb in its's name.

The raison d'etre of a getter is not do something but to evaluate to something. We are not interested in what the method does. Since it has no side effects, whatever computation goes on in the method cannot be of any interest. We are only interested in what the method returns. The method name should reflect that in the form of a noun. Method names consisting only of nouns should always be "getters".

The information in the prefix "get" can be inferred from the lack of verbs. This is simpler and more intuitive than using the get prefix.

A method whose name consists of only a noun and has a return value can be assumed to have no side effects and to be relatively cheap. A method whose name contains a verb and does not have a return value exists to have side effects. A method whose name contains a verb and has a return value can be assumed to be relatively expensive and may have side effects.

It seems the reason everybody is writing "get" all over the place is merely dogmatic tradition originating from the JavaBeans pattern. Leave the get prefix for when you actually plan to use tools/frameworks that need it!

Answer 9

Personally, I am addicted to get. It is just the human language. When you want something, you want to get something. There is nothing wrong with get prefixes. About the naming convention, I can think of the Select prefix for database queries - SelectUsers for example.

Answer 10

As many people have already stated, get..() and set()... are part of the Java Beans Convention. This is necessary for interoperation with other parts of the Java Spec. For example, in JSP you can access members from a Java been by specifying the property name without the get prefix.

Given the bean:-

public class Foo {
  public int getX() { return 1; }
}

We can do the following JSP to get X: -

<jsp:useBean id="aFoo" class="Foo" />
<c:out value="${aFoo.X}" />

Are there naming conventions other than "get" for this kind of methods?

Yes you can use is instead of get for boolean properties.

Answer 11

What does "get" matter when we live in a day and age where any IDE that's worth having will generate getters and setters for your private variables and lets you fold them up if you'd rather not read them?

Your real issue should be about design: Why do your objects have so many attributes? If your objects have nothing but getters and setters, are you suffering from an "anemic domain model"?

The C# {get, set} notation is marginally better, because it cuts down on the lines of code, but you still have that pesky "get" to type for every variable.

Answer 12

As others have mentioned, it is for Java Beans. However, if you are using Java, PLEASE only name a method getXXX() if it only returns a value and does nothing else. Like you hinted at, if it is doing something else, name it something different such as computeXXX().

I sometimes find getXXX() methods with 50 lines of code - if this is the case, you are doing it wrong.

Answer 13

I am starting to feel that the word "get" is losing its meaning because of inflation. It is noise in my code.

I would slightly disagree with this conclusion. I wouldn't say it loses its meaning, I would say that as it is widely used that methods with the get prefix will do pretty much what you expect them to do.

For the following example:

Time.isoFormattedDateString(Date date)

Does this set the format type based on the input parameter so all subsequent calls will use this format?

I know it is a bit of a stretch that someone would come to that conclusion as it is a static method but would you be as sure if this method was called on an instance? Probably, but the use of get removes all ambiguity:

getIsoFormattedDateString(Date date)

In my opinion, properties are a more elegant solution than dropping get altogether.

Answer 14

Historical snippet: If you look at some of the very earliest Java 1.0 APIs (pre JavaBeans), you'll see they don't have the 'get' prefix. For example java.awt.Container#minimumSize() was deprecated in replace by #getMinimumSize().

Answer 15

I think this is a subset of the "give your variables and functions meaningful names" ideal.

"get" has a specific meaning in Java Beans as many have noted. I think it should therefore be limited to being used to retrieve the value of an internal variable, possibly with side effects. I think it's acceptable if "getting" involves minor computation, like doing a data type conversion or extracting a value from an embedded class or reinterprerting other values, like "public int getRightMargin() { return width-margin.left; }". Any side effects should be limited to things that are truly "side effects" of getting the value, like setting a flag that says it has been retrieved.

But if there's serious computation, I don't think it should be called "get". Maybe "calc" or whatever.

It would be good if we had consistent terms to use in naming functions, like if we all agreed that "read" means that the main activity is to retrieve something from a database while "calc" meant to do calculations or some such. But that might be unrealistic: maybe there are too many cases with subtle differences.

Answer 16

One option is to keep the get prefix for methods that return primitive or immutable values, but drop the prefix for methods that return references that can be used to modify the original recipient.

e.g. in java.util.Map, size() could be called getSize() but keySet() would not be called getKeySet().

Answer 17

I use get and set only for methodes that only get or set a property and not mutch else.

Answer 18

Well, although JavaBeans spec asks you to declare getters and setters, I usually will not declare them unless it's absolutely necessary (as in case of many MVC frameworks). I did a lot of swing in my Java career and I tend to declare variables as public (yeah it sounds a bit non OOPy). But I liked it since it looked concise and 'I' know what I'm doing. The only advantage that it had is the reduced number of lines.

Answer 19

Java Beans get very sticky to its naming conventions, like suppose you declare a variable name Name, with corresponding setter as setName(). But it would generate an error as, setName must correspond to 'name' instead of Name. Another example boolean isReadey; with getter isReady(). Again error as it look for boolean ready. So, prior to code you must be familiar with this naming convention. But i personally prefer this convention as it makes programmer's work easy and seems to be a bit logical after few moments u spend with it.

Answer 20

It's important that the "get" prefix remains because:

• a method should state an action, therefore it must contain a verb in its name

• get shows that the state of a variable won't change

• how easy would you distinguish the method account() from the variable account in this expression :

  newAccount = currentAccount + account() --- what does this account() do ?

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The reason you see too much getters in your code should worry you!

• Either you separate your classes to smaller ones or
• just hide your code better, because you don't have to reveal your classes interns and even should try to hide them as much as you can!