Thinking about naming of utility classes in java

Question

I am looking for naming guidlines for non functional (utility) extensions of the common classes.

In C# I used to use some of this:

1) ListExtensions, too long but with extension methods ListExtensions never appears. Usage is just. var productList = new List(); productList.MyExtendedMehod();

2) ListHelpers. This was in old C# 2.0 era, usage is ListHelpers.MyExtendedMethod(productList );

Now I am diving with java. What I have learned is Collections, Arrays classes. So how do you name your helper classes. CollectionUtils? Collections? CollectionsEx?

Answer 1

I think XXXUtils is the common way. Then you can use static imports to get rid of the class name.

class FooUtils {
  public static foo(int x) { ... }
}

static import FooUtils.foo;
foo(5);

Answer 2

Check out the Apache Commons Collections library for some naming ideas. Maybe this library does a lot of things you want to do anyway!

Answer 3

1) I haven't seen it a lot, but I believe the good naming scheme is to give a functional name (SynchronizedSet, etc.). You can get examples from Apache's commons-collections or google collections.

2) The "standard" suffix is Utils - SwingUtils, StringUtils, etc.

Answer 4

Apache Commons has set quite a standard by using XXXUtils pattern.

Answer 5

In Java there's a pattern of using plurals like java.util.Collections to hold global function-like static methods for the corresponding class/package.

For example,

Collections.shuffle(list);

shuffles the list.

Answer 6

I always try and use the package name in plural form. Its shorter than Util or Utils and it sounds more english like.

I believe Arrays and Collections from the JDK sound so much better than if they were named ArrayUtils or CollectionUtils.

For a train package my utils would be placed inside a class called Trains.

Answer 7

Personally I try to choose utility class names such that the clase name is part of the method name. For example

list = As.list(array);
set = As.set(list);
b = All.notNull(foo, bar, qux, ...);
name = Defaults.to(input, "Joe Random");
value = For.example(StackTest.class, "withSomeValues"); 
b = Is.empty(iterable);
Out.put("Hello, Worlds!");

et cetera...