OuterTypeNumber

Since Checkstyle 5.0

Description

Checks for the number of types declared at the outer (or root) level in a file.

Rationale: It is considered good practice to only define one outer type per file.

Properties

name	description	type	default value	since
max	Specify the maximum number of outer types allowed.	int	`1`	5.0

Examples

To configure the check to accept 1 outer type per file:


<module name="Checker">
  <module name="TreeWalker">
    <module name="OuterTypeNumber"/>
  </module>
</module>

Example:


// violation 2 lines above 'Outer types defined is 3 (max allowed is 1)'

public class Example1 {
}

class Example {
  void exampleMethod() {}
}

enum outer {
}

To configure the check to accept 2 outer types per file:


<module name="Checker">
  <module name="TreeWalker">
    <module name="OuterTypeNumber">
      <property name="max" value="3"/>
    </module>
  </module>
</module>

Example:


public class Example2 {
}

class Examples {
  void exampleMethod() {}
}

enum outer1 {
}

Example of Usage

Checkstyle Style

Violation Messages

maxOuterTypes

All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.

Package

com.puppycrawl.tools.checkstyle.checks.sizes

Parent Module

TreeWalker