Vert.x code style guidelines

All Java code code in the vertx-core repository or any repositories under the vert-x3 organisation must adhere to this guidelines.

Any non Java code should try and remain as to close to them as possible, where appropriate.

Our guidelines should be familiar to most developers as they are pretty much the IntelliJ defaults / Oracle codestyle guidelines with some minor changes. So they're pretty much defacto standard Java code style anyway.

We recommend that all repos should have a .editorconfig in the root folder with at least the following content:

root = true

[*]
charset = utf-8
indent_style = space
indent_size = 2
trim_trailing_whitespace = true
end_of_line = lf
insert_final_newline = true

Having such file will out of the box allow you to follow the basic guidelines regarding line ending, spacing, tabs in IntelliJ and many other IDE's and for IDE's that do not support it out of the box there are plugins.

Fundamentally you should be able to infer the guidelines just by looking at the current code in a master branch. However for clarity here they are:

Indentation

We use a variation of the 1TBS 1TBS (One True Brace Style) - this is basically a variation of K&R style, and is characterised by breaking after the opening brace of a code block, including classes Here is an example:

class Foo {
  void aMethod(int x) {
    if (x == 3) {
      doSomething();
    } else {
      doSomethingElse();
    } 
  }
}

Tab / spaces

We never use tabs, only spaces. Number of spaces in an indent is always 2. We use this small number because there's sometimes quite a lot of nested indents in callback based code.

Other Whitespace

Blank lines

We generally don't use a lot whitespace, e.g. blank lines between code. But feel free to use them where they aid clarity. Don't go overboard.

Whitespace in expressions

Do this:

if (x == 3) {
}

Don't do this:

if (x==3) {
}

Or this:

if ( x == 3 ) {
}

Or this:

if (  x==3  ) {
}

Do this:

for (int i = 0; i < 10; i++) {
}

Not this:

for (int i = 0;i < 10;i++) {
}

Page width

Max page width is 120 chars, not 80. We don't program on green screens or print stuff using line printers any more.