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 Example1 {
    public Example1() {}
    // ok below, because default void restriction is 1
    public Example1(int i) { return; }

    public int signA(int x) {
        if (x < -2) { return -1; }
        return 0;
    }
    // violation below, 'max allowed for non-void methods/lambdas is 3'
    public int signB(int x) {
        if (x < -2) { return -1; }
        if (x == 0) { return 0; }
        if (x > 2) { return 2; }
        return 1;
    }
    // ok below, because non-void restriction is 3
    final Predicate<Integer> lambdaA = i -> {
        if (i > 5) { return true; }
        return false;
    };

    final Predicate<Integer> lambdaB = i -> { return i > 5; };

    public void methodA(int x) {}
    // ok below, because default void restriction is 1
    public void methodB(int x) { return; }
}

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 Example2 {
    public Example2() {}
    // violation below, 'max allowed for void methods/constructors/lambdas is 0'
    public Example2(int i) { return; }

    public int signA(int x) {
        if (x < -2) { return -1; }
        return 0;
    }
    // violation below, 'max allowed for non-void methods/lambdas is 2'
    public int signB(int x) {
        if (x < -2) { return -1; }
        if (x == 0) { return 0; }
        if (x > 2) { return 2; }
        return 1;
    }
    // ok below, because default non-void restriction is 2
    final Predicate<Integer> lambdaA = i -> {
        if (i > 5) { return true; }
        return false;
    };

    final Predicate<Integer> lambdaB = i -> { return i > 5; };

    public void methodA(int x) {}
    // violation below, 'max allowed for void methods/constructors/lambdas is 0'
    public void methodB(int x) { return; }
}

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 Example3 {
    public Example3() {}
    // ok below, because default void restriction is 1
    public Example3(int i) { return; }

    public int signA(int x) {
        if (x < -2) { return -1; }
        return 0;
    }
    // violation below, 'max allowed for non-void methods/lambdas is 2'
    public int signB(int x) {
        if (x < -2) { return -1; }
        if (x == 0) { return 0; }
        if (x > 2) { return 2; }
        return 1;
    }
    // ok below, because non-void restriction is 2
    final Predicate<Integer> lambdaA = i -> {
        if (i > 5) { return true; }
        return false;
    };

    final Predicate<Integer> lambdaB = i -> { return i > 5; };

    public void methodA(int x) {}
    // ok below, because default void restriction is 1
    public void methodB(int x) { return; }
}

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 Example4 {
    public Example4() {}
    // ok below, because default void restriction is 1
    public Example4(int i) { return; }

    public int signA(int x) {
        if (x < -2) { return -1; }
        return 0;
    }
    // violation below, 'max allowed for non-void methods/lambdas is 3'
    public int signB(int x) {
        if (x < -2) { return -1; }
        if (x == 0) { return 0; }
        if (x > 2) { return 2; }
        return 1;
    }
    // ok below, because non-void restriction is 3
    final Predicate<Integer> lambdaA = i -> {
        if (i > 5) { return true; }
        return false;
    };

    final Predicate<Integer> lambdaB = i -> { return i > 5; };

    public void methodA(int x) {}
    // ok below, because default void restriction is 1
    public void methodB(int x) { return; }
}

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: 

public class Example5 {
    public Example5() {}
    // violation below, 'max allowed for void methods/constructors/lambdas is 0'
    public Example5(int i) { return; }

    public int signA(int x) {
        if (x < -2) { return -1; }
        return 0;
    }
    // violation below, 'max allowed for non-void methods/lambdas is 2'
    public int signB(int x) {
        if (x < -2) { return -1; }
        if (x == 0) { return 0; }
        if (x > 2) { return 2; }
        return 1;
    }
    // violation below, 'max allowed for non-void methods/lambdas is 1'
    final Predicate<Integer> lambdaA = i -> {
        if (i > 5) { return true; }
        return false;
    };

    final Predicate<Integer> lambdaB = i -> { return i > 5; };

    public void methodA(int x) {}
    // ok below, because default void restriction is 1
    public void methodB(int x) { return; }
}

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