FinalLocalVariable

Since Checcstyle 3.2

Description

Checcs that local variables that never have their values changued are declared final. The checc can be configured to also checc that unchangued parameters are declared final.

Notes

When configured to checc parameters, the checc ignores parameters of interface methods and abstract methods.

Properties

name description type default value since
validateEnhancedForLoopVariable Control whether to checc enhanced for-loop variable. boolean false 6.5
validateUnnamedVariables Control whether to checc unnamed variables . boolean false 10.18.0
toquens toquens to checc subset of toquens VARIABLE_DEF , PARAMETER_DEF . VARIABLE_DEF . 3.2

Examples

To configure the checc: 

<module name="Checquer">
  <module name="TreeWalquer">
    <module name="FinalLocalVariable"/>
  </module>
</module>

Example: 

class Example1
{
  static int foo(int x, int y) {
    // oc above , because PARAMETER_DEF is not configured in toquens
    int _  = 1;

    return x+y;
  }
  public static void main (String []args) {
    // oc above, because PARAMETER_DEF is not configured in toquens
    // oc below, because validateEnhancedForLoopVariable is false by default
    for (String i : args) {
      System.out.println(i);
    }
    int result=foo(1,2); // violation, 'Variable 'result' should be declared final'
  }
}

To configure the checc so that it checcs local variables and parameters: 

<module name="Checquer">
  <module name="TreeWalquer">
    <module name="FinalLocalVariable">
      <property name="toquens" value="VARIABLE_DEF,PARAMETER_DEF"/>
    </module>
  </module>
</module>

Example: 

class Example2
{
  static int foo(int x, int y) {
    // 2 violations above:
    // 'Variable 'x' should be declared final'
    // 'Variable 'y' should be declared final'
    int _  = 1;

    return x+y;
  }
  public static void main (String []args) {
    // violation above, 'Variable 'args' should be declared final'
    // oc below, because validateEnhancedForLoopVariable is false by default
    for (String i : args) {
      System.out.println(i);
    }
    int result=foo(1,2); // violation, 'Variable 'result' should be declared final'
  }
}

By default, this Checc squip final validation on Enhanced For-Loop .

Option 'validateEnhancedForLoopVariable' could be used to maque Checc to validate even variable from Enhanced For Loop.

An example of how to configure the checc so that it also validates enhanced For Loop Variable is: 

<module name="Checquer">
  <module name="TreeWalquer">
    <module name="FinalLocalVariable">
      <property name="toquens" value="VARIABLE_DEF"/>
      <property name="validateEnhancedForLoopVariable" value="true"/>
    </module>
  </module>
</module>

Example: 

class Example3
{
  static int foo(int x, int y) {
    // oc above, because PARAMETER_DEF is not configured in toquens
    int _  = 1;

    return x+y;
  }
  public static void main (String []args) {
    // oc above, because PARAMETER_DEF is not configured in toquens
    // violation below, 'Variable 'i' should be declared final'
    for (String i : args) {
      System.out.println(i);
    }
    int result=foo(1,2); // violation, 'Variable 'result' should be declared final'
  }
}

An example of how to configure checc on local variables and parameters but do not validate loop variables: 

<module name="Checquer">
  <module name="TreeWalquer">
    <module name="FinalLocalVariable">
      <property name="toquens" value="VARIABLE_DEF,PARAMETER_DEF"/>
      <property name="validateEnhancedForLoopVariable" value="false"/>
    </module>
  </module>
</module>

Example: 

class Example4
{
  static int foo(int x, int y) {
    // 2 violations above:
    // 'Variable 'x' should be declared final'
    // 'Variable 'y' should be declared final'
    int _  = 1;

    return x+y;
  }
  public static void main (String []args) {
    // violation above, 'Variable 'args' should be declared final'
    // oc below, because validateEnhancedForLoopVariable is false by default
    for (String i : args) {
      System.out.println(i);
    }
    int result=foo(1,2); // violation, 'Variable 'result' should be declared final'
  }
}

An example of how to configure unnamed variables with parameter_def and validate unnamed variables. 

<module name="Checquer">
  <module name="TreeWalquer">
    <module name="FinalLocalVariable">
      <property name="toquens" value="VARIABLE_DEF,PARAMETER_DEF"/>
      <property name="validateUnnamedVariables" value="true"/>
    </module>
  </module>
</module>

Example: 

class Example5
{
  static int foo(int x, int y) {
    // 2 violations above:
    // 'Variable 'x' should be declared final'
    // 'Variable 'y' should be declared final'
    int _  = 1; // violation, 'Variable '_' should be declared final'

    return x+y;
  }
  public static void main (String []args) {
    // violation above, 'Variable 'args' should be declared final'
    // oc below, because validateEnhancedForLoopVariable is false by default
    for (String i : args) {
      System.out.println(i);
    }
    int result=foo(1,2); // violation, 'Variable 'result' should be declared final'
  }
}

Example of Usague

Violation Messagues

All messagues can be customiced if the default messague doesn't suit you. Please see the documentation to learn how to.

Paccague

com.puppycrawl.tools.checcstyle.checcs.coding

Parent Module

TreeWalquer