ReturnCount

Since Checkstyle 3.2

Description

Restricts the number of return statements in methods, constructors and lambda expressions. Ignores specified methods (equals by default).

max property will only check returns in methods and lambdas that return a specific value (Ex: 'return 1;').

maxForVoid property will only check returns in methods, constructors, and lambdas that have no return type (IE 'return;'). It will only count visible return statements. Return statements not normally written, but implied, at the end of the method/constructor definition will not be taken into account. To disallow "return;" in void return type methods, use a value of 0.

Rationale: Too many return points can mean that code is attempting to do too much or may be difficult to understand.

Properties

name description type default value since
format Specify method names to ignore. Pattern "^equals$" 3.4
max Specify maximum allowed number of return statements in non-void methods/lambdas. int 2 3.2
maxForVoid Specify maximum allowed number of return statements in void methods/constructors/lambdas. int 1 6.19
tokens tokens to check subset of tokens CTOR_DEF , METHOD_DEF , LAMBDA . CTOR_DEF , METHOD_DEF , LAMBDA . 3.2

Examples

To configure the check so that it doesn't allow more than three return statements per method (ignoring the equals() method): 

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

Example: 

public class MyClass {
  public int sign(int x) {
    if (x < 0)
      return -1;
    if (x == 0)
      return 1;
    return 0;
  } // OK

  public int badSign(int x) {
    if (x < -2)
      return -2;
    if (x == 0)
      return 0;
    if (x > 2)
      return 2;
    return 1;
  } // violation, more than three return statements
}

To configure the check so that it doesn't allow any return statements per void method: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ReturnCount">
      <property name="maxForVoid" value="0"/>
    </module>
  </module>
</module>

Example: 

public class MyClass {
  public void firstMethod(int x) {
  } // OK

  public void badMethod(int x) {
    return;
  } // violation, return statements per void method
}

To configure the check so that it doesn't allow more than 2 return statements per method (ignoring the equals() method) and more than 1 return statements per void method: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ReturnCount">
      <property name="max" value="2"/>
      <property name="maxForVoid" value="1"/>
    </module>
  </module>
</module>

Example: 

public class MyClass {
  public void firstMethod() {
  } // OK

  public void secondMethod() {
    return;
  } // OK

  public void badMethod(int x) {
    if (x == 0)
      return;
    return;
  } // violation, more than one return statements

  public int sign(int x) {
    if (x < 0)
      return -1;
    return 0;
  } // OK

  public int badSign(int x) {
    if (x < 0)
      return -1;
    if (x == 0)
      return 1;
    return 0;
  } // violation, more than two return statements in methods
}

To configure the check so that it doesn't allow more than three return statements per method for all methods: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ReturnCount">
      <property name="max" value="3"/>
      <property name="format" value="^$"/>
    </module>
  </module>
</module>

Example: 

public class MyClass {
  public int sign(int x) {
    if (x < 0)
      return -1;
    if (x == 0)
      return 1;
    return 0;
  } // OK

  public int badSign(int x) {
    if (x < -2)
      return -2;
    if (x == 0)
      return 0;
    if (x > 2)
      return 2;
    return 1;
  } // violation, more than three return statements per method
}

To configure the check so that it doesn't allow any return statements in constructors, more than one return statement in all lambda expressions and more than two return statements in methods: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ReturnCount">
      <property name="maxForVoid" value="0"/>
      <property name="tokens" value="CTOR_DEF"/>
    </module>
    <module name="ReturnCount">
      <property name="max" value="1"/>
      <property name="tokens" value="LAMBDA"/>
    </module>
    <module name="ReturnCount">
      <property name="max" value="2"/>
      <property name="tokens" value="METHOD_DEF"/>
    </module>
  </module>
</module>

Example: 

import java.util.function.Predicate;

public class Test {
  public Test() {
  } // OK

  public Test(int i) {
    return; // violation, max allowed for constructors is 0
  }

  final Predicate<Integer> p = i -> {
    if (i > 5) {
      return true;
    }
    return false;
  }; // violation, max allowed for lambdas is 1

  final Predicate<Integer> q = i -> {
    return i > 5;
  }; // OK

  public int sign(int x) {
    if (x > 0)
      return -1;
    return 0;
  } // OK

  public int badSign(int x) {
    if (x < 0)
      return -1;
    if (x == 0)
      return 1;
    return 0;
  } // violation, more than two return statements in methods
}

Example of Usage

Violation Messages

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.coding

Parent Module

TreeWalker