Since Checkstyle 3.2
Checks for long anonymous inner classes.
Rationale: If an anonymous inner class becomes very long it is hard to understand and to see the flow of the method where the class is defined. Therefore long anonymous inner classes should usually be refactored into a named inner class. See also Bloch, Effective Java, p. 93.
| name | description | type | default value | since |
|---|---|---|---|---|
| max | maximum allowable number of lines | Integer | 20 | 3.2 |
To configure the check to accept files with up to 60 lines:
<module name="AnonInnerLength">
<property name="max" value="60"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.2
Restricts the number of executable statements to a specified limit.
| name | description | type | default value | since |
|---|---|---|---|---|
| max | the maximum threshold allowed | Integer | 30 | 3.2 |
| tokens | tokens to check | subset of tokens CTOR_DEF, METHOD_DEF, INSTANCE_INIT, STATIC_INIT. | CTOR_DEF, METHOD_DEF, INSTANCE_INIT, STATIC_INIT. | 3.2 |
To configure the check:
<module name="ExecutableStatementCount"/>
To configure the check with a threshold of 20 for constructor and method definitions:
<module name="ExecutableStatementCount">
<property name="max" value="20"/>
<property name="tokens" value="CTOR_DEF,METHOD_DEF"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 5.0
Checks for long source files.
Rationale: If a source file becomes very long it is hard to understand. Therefore long classes should usually be refactored into several individual classes that focus on a specific task.
| name | description | type | default value | since |
|---|---|---|---|---|
| max | maximum allowable number of lines | Integer | 2000 | 3.2 |
| fileExtensions | file type extension of files to process | String Set | all files | 5.0 |
To configure the check to accept files with up to 1500 lines:
<module name="FileLength">
<property name="max" value="1500"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.0
Checks for long lines.
Rationale: Long lines are hard to read in printouts or if developers have limited screen space for the source code, e.g. if the IDE displays additional information like project tree, class hierarchy, etc.
| name | description | type | default value | since |
|---|---|---|---|---|
| ignorePattern | pattern for lines to ignore | Regular Expression | "^$" | 3.0 |
| max | maximum allowable line length | Integer | 80 | 3.0 |
To configure the check to accept lines up to 120 characters long:
<module name="LineLength">
<property name="max" value="120"/>
</module>
To configure the check to ignore lines that begin with " * ", followed by just one word, such as within a Javadoc comment:
<module name="LineLength">
<property name="ignorePattern" value="^ *\* *[^ ]+$"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 5.3
Checks the number of methods declared in each type declaration by access modifier or total count.
This check can be configured to flag classes that define too many methods to prevent the class from getting too complex. Counting can be customized to prevent too many total methods in a type definition (maxTotal), or to prevent too many methods of a specific access modifier (private, package, protected or public). Each count is completely separated to customize how many methods of each you want to allow. For example, specifying a maxTotal of 10, still means you can prevent more than 0 maxPackage methods. A violation won't appear for 8 public methods, but one will appear if there is also 3 private methods or any package-private methods.
Methods defined in anonymous classes are not counted towards any totals. Counts only go towards the main type declaration parent, and are kept separate from it's children's inner types.
public class ExampleClass {
public enum Colors {
RED, GREEN, YELLOW;
public String getRGB() { ... } // NOT counted towards ExampleClass
}
public void example() { // counted towards ExampleClass
Runnable r = (new Runnable() {
public void run() { ... } // NOT counted towards ExampleClass and won't produce any violations
});
}
public static class InnerExampleClass {
protected void example2() { ... } // NOT counted towards ExampleClass,
// but counted towards InnerExampleClass
}
}
| name | description | type | default value | since |
|---|---|---|---|---|
| maxTotal | maximum allowable number of methods at all scope levels | Integer | 100 | 5.3 |
| maxPrivate | maximum allowable number of private methods | Integer | 100 | 5.3 |
| maxPackage | maximum allowable number of package methods | Integer | 100 | 5.3 |
| maxProtected | maximum allowable number of protected methods | Integer | 100 | 5.3 |
| maxPublic | maximum allowable number of public methods | Integer | 100 | 5.3 |
| tokens | tokens to check | subset of tokens CLASS_DEF, ENUM_CONSTANT_DEF, ENUM_DEF, INTERFACE_DEF, ANNOTATION_DEF. | CLASS_DEF, ENUM_CONSTANT_DEF, ENUM_DEF, INTERFACE_DEF, ANNOTATION_DEF. | 5.3 |
To configure the check with defaults:
<module name="MethodCount"/>
To configure the check to allow no more than 30 methods per type declaration:
<module name="MethodCount">
<property name="maxTotal" value="30"/>
</module>
To configure the check to allow no more than 10 public methods per type declaration, and 40 methods in total:
<module name="MethodCount">
<property name="maxPublic" value="10"/>
<property name="maxTotal" value="40"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.0
Checks for long methods and constructors.
Rationale: If a method becomes very long it is hard to understand. Therefore long methods should usually be refactored into several individual methods that focus on a specific task.
| name | description | type | default value | since |
|---|---|---|---|---|
| max | maximum allowable number of lines | Integer | 150 | 3.0 |
| countEmpty | whether to count empty lines and single line comments of the form // | Boolean | true | 3.2 |
| tokens | tokens to check | subset of tokens METHOD_DEF, CTOR_DEF. | METHOD_DEF, CTOR_DEF. | 3.0 |
To configure the check:
<module name="MethodLength"/>
To configure the check so that it accepts methods with at most 60 lines:
<module name="MethodLength">
<property name="tokens" value="METHOD_DEF"/>
<property name="max" value="60"/>
</module>
To configure the check so that it accepts methods with at most 60 lines, not counting empty lines and single line comments:
<module name="MethodLength">
<property name="tokens" value="METHOD_DEF"/>
<property name="max" value="60"/>
<property name="countEmpty" value="false"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 5.0
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.
| name | description | type | default value | since |
|---|---|---|---|---|
| max | maximum allowable number of outer types | Integer | 1 | 5.0 |
To configure the check to accept 1 outer type per file:
<module name="OuterTypeNumber"/>
To configure the check to accept 2 outer types per file:
<module name="OuterTypeNumber">
<property name="max" value="2"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| max | maximum allowable number of parameters | Integer | 7 | 3.0 |
| ignoreOverriddenMethods | Ignore number of parameters for methods with @Override annotation | Boolean | false | 6.2 |
| tokens | tokens to check | subset of tokens METHOD_DEF, CTOR_DEF. | METHOD_DEF, CTOR_DEF. | 3.0 |
To configure the check:
<module name="ParameterNumber"/>
To configure the check to allow 10 parameters for a method:
<module name="ParameterNumber">
<property name="max" value="10"/>
<property name="tokens" value="METHOD_DEF"/>
</module>
To configure the check to ignore number of parameters for methods with @Override or @java.lang.Override annotation.
Rationale: developer may need to override method with many parameters from 3-rd party library. In this case developer has no control over number of parameters.
<module name="ParameterNumber">
<property name="ignoreOverriddenMethods" value="true"/>
<property name="tokens" value="METHOD_DEF"/>
</module>
Java code example
@Override
public void needsLotsOfParameters(int a, int b, int c, int d, int e, int f, int g, int h) {
...
}
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.