| layout | title |
|---|---|
scalastyle |
Scalastyle: Implemented Rules |
There are 48 rules which are currently implemented:
- id - file.size.limit
- description - Check the number of lines in a file
- class - org.scalastyle.file.FileLengthChecker
- default level - WarningLevel
Files which are too long can be hard to read and understand.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maxFileLength | Maximum file length | integer | 1500 |
<check enabled="true" class="org.scalastyle.file.FileLengthChecker" level="warning"> <parameters> <parameter name="maxFileLength">800</parameter> </parameters> </check>
- id - line.size.limit
- description - Check the number of characters in a line
- class - org.scalastyle.file.FileLineLengthChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maxLineLength | Maximum line length | integer | 160 |
| tabSize | Tab size | integer | 4 |
TBD
- id - line.contains.tab
- description - Check that there are no tabs in a file
- class - org.scalastyle.file.FileTabChecker
- default level - WarningLevel
No parameters
TBD
- id - header.matches
- description - Check the first lines of each file matches the text
- class - org.scalastyle.file.HeaderMatchesChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| header | Header | string |
TBD
- id - newline.at.eof
- description - Checks that a file ends with a newline character
- class - org.scalastyle.file.NewLineAtEofChecker
- default level - WarningLevel
Some version control systems don't cope well with files which don't end with a newline character.
No parameters
<check enabled="true" class="org.scalastyle.file.NewLineAtEofChecker" level="warning"/>
org.scalastyle.file.NoNewLineAtEofChecker - Checks that a file does not end with a newline character
- id - no.newline.at.eof
- description - Checks that a file does not end with a newline character
- class - org.scalastyle.file.NoNewLineAtEofChecker
- default level - WarningLevel
Because Mirco Dotta wanted it.
No parameters
<check enabled="true" class="org.scalastyle.file.NoNewlineAtEofChecker" level="warning"/>
org.scalastyle.file.RegexChecker - Checks that a regular expression cannot be matched, if found reports this
- id - regex
- description - Checks that a regular expression cannot be matched, if found reports this
- class - org.scalastyle.file.RegexChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string |
<check enabled="true" class="org.scalastyle.file.RegexChecker" level="warning"> <parameters> <parameter name="regex">(?m)^\s*$(\r|)\n^\s*$(\r|)\n</parameter> </parameters> <customMessage>No double blank lines</customMessage> </check>
org.scalastyle.file.WhitespaceEndOfLineChecker - Check that there is no trailing whitespace at the end of lines
- id - whitespace.end.of.line
- description - Check that there is no trailing whitespace at the end of lines
- class - org.scalastyle.file.WhitespaceEndOfLineChecker
- default level - WarningLevel
No parameters
TBD
- id - block.import.checker
- description - Checks that block imports are not used.
- class - org.scalastyle.scalariform.BlockImportChecker
- default level - WarningLevel
Block imports can lead to annoying merge errors in large code bases that are maintained by lot of developers. This rule allows to ensure that only single imports are used in order to minimize merge errors in import declarations.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.BlockImportChecker" level="warning"/>
- id - class.name
- description - Check that class names match a regular expression
- class - org.scalastyle.scalariform.ClassNamesChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string | ^[A-Z][A-Za-z]*$ |
TBD
org.scalastyle.scalariform.ClassTypeParameterChecker - Checks that type parameter to a class matches a regular expression
- id - class.type.parameter.name
- description - Checks that type parameter to a class matches a regular expression
- class - org.scalastyle.scalariform.ClassTypeParameterChecker
- default level - WarningLevel
Scala generic type names are generally single upper case letters. This check checks for classes and traits.
Note that this check only checks the innermost type parameter, to allow for List[T].
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string | ^[A-Z_]$ |
<check enabled="true" class="org.scalastyle.scalariform.ClassTypeParameterChecker" level="warning"> <parameters> <parameter name="regex">^[A-Z_]$</parameter> </parameters> </check>
org.scalastyle.scalariform.CovariantEqualsChecker - Check that classes and objects do not define equals without overriding equals(java.lang.Object).
- id - covariant.equals
- description - Check that classes and objects do not define equals without overriding equals(java.lang.Object).
- class - org.scalastyle.scalariform.CovariantEqualsChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.CyclomaticComplexityChecker - Checks that the cyclomatic complexity of a method does exceed a value
- id - cyclomatic.complexity
- description - Checks that the cyclomatic complexity of a method does exceed a value
- class - org.scalastyle.scalariform.CyclomaticComplexityChecker
- default level - WarningLevel
If the code is too complex, then this can make code hard to read.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maximum | Maximum | integer | 10 |
<check enabled="true" class="org.scalastyle.scalariform.CyclomaticComplexityChecker" level="warning"> <parameters> <parameter name="maximum">10</parameter> </parameters> </check>
org.scalastyle.scalariform.DeprecatedJavaChecker - Checks that Java @Deprecated is not used, Scala @deprecated should be used instead
- id - deprecated.java
- description - Checks that Java @Deprecated is not used, Scala @deprecated should be used instead
- class - org.scalastyle.scalariform.DeprecatedJavaChecker
- default level - WarningLevel
You should be using the Scala @deprecated instead.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.DeprecatedJavaChecker" level="warning"/>
org.scalastyle.scalariform.EmptyClassChecker - If a class/trait has no members, the braces are unnecessary
- id - empty.class
- description - If a class/trait has no members, the braces are unnecessary
- class - org.scalastyle.scalariform.EmptyClassChecker
- default level - WarningLevel
If a class / trait has no members, then braces are unnecessary, and can be removed.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.EmptyClassChecker" level="warning"/>
org.scalastyle.scalariform.EqualsHashCodeChecker - Check that if a class implements either equals or hashCode, it should implement the other
- id - equals.hash.code
- description - Check that if a class implements either equals or hashCode, it should implement the other
- class - org.scalastyle.scalariform.EqualsHashCodeChecker
- default level - WarningLevel
No parameters
TBD
- id - if.brace
- description - Checks that if statement have braces
- class - org.scalastyle.scalariform.IfBraceChecker
- default level - WarningLevel
A lowercase L (l) can look similar to a number 1 with some fonts.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| singleLineAllowed | Single Line Allowed | boolean | true |
| doubleLineAllowed | Double Line Allowed | boolean | false |
<check enabled="true" class="org.scalastyle.scalariform.IfBraceChecker" level="warning"> <parameters> <parameter name="singleLineAllowed">true</parameter> <parameter name="doubleLineAllowed">false</parameter> </parameters> </check>
org.scalastyle.scalariform.IllegalImportsChecker - Check that a class does not import certain classes
- id - illegal.imports
- description - Check that a class does not import certain classes
- class - org.scalastyle.scalariform.IllegalImportsChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| illegalImports | Illegal Imports | string | sun._,java.awt._ |
TBD
org.scalastyle.scalariform.ImportGroupingChecker - Checks that imports are grouped together, not throughout the file
- id - import.grouping
- description - Checks that imports are grouped together, not throughout the file
- class - org.scalastyle.scalariform.ImportGroupingChecker
- default level - WarningLevel
If imports are spread throughout the file, knowing what is in scope at any one place can be difficult to work out.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.ImportGroupingChecker" level="warning"/>
org.scalastyle.scalariform.LowercasePatternMatchChecker - Checks that a case statement pattern match is not lower case, as this can cause confusion
- id - lowercase.pattern.match
- description - Checks that a case statement pattern match is not lower case, as this can cause confusion
- class - org.scalastyle.scalariform.LowercasePatternMatchChecker
- default level - WarningLevel
A lower case pattern match clause with no other tokens is the same as _; this is not true for patterns which start with an upper case letter. This can cause confusion, and may not be what was intended:
val foo = "foo"
val Bar = "bar"
"bar" match { case Bar => "we got bar" } // result = "we got bar"
"bar" match { case foo => "we got foo" } // result = "we got foo"
"bar" match { case `foo` => "we got foo" } // result = MatchError
This checker raises a warning with the second match. To fix it, use an identifier which starts with an upper case letter (best), use case _ or,
if you wish to refer to the value, add a type : Any
val lc = "lc"
"something" match { case lc: Any => "lc" } // result = "lc"
"something" match { case _ => "lc" } // result = "lc"
No parameters
<check enabled="true" class="org.scalastyle.scalariform.LowercasePatternMatchChecker" level="warning"/>
- id - magic.number
- description - Checks for use of magic numbers
- class - org.scalastyle.scalariform.MagicNumberChecker
- default level - WarningLevel
Replacing a magic number with a named constant can make code easier to read and understand, and can avoid some subtle bugs.
A simple assignment to a val is not considered to be a magic number, for example:
val foo = 4
is not a magic number, but
var foo = 4
is considered to be a magic number.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| ignore | Ignore | string | -1,0,1,2 |
<check enabled="true" class="org.scalastyle.scalariform.MagicNumberChecker" level="warning"> <parameters> <parameter name="ignore">-1,0,1,2,3</parameter> </parameters> </check>
- id - method.length
- description - Checks that methods do not exceed a maximum length
- class - org.scalastyle.scalariform.MethodLengthChecker
- default level - WarningLevel
Long methods can be hard to read and understand.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maxLength | Maximum length | integer | 50 |
<check enabled="true" class="org.scalastyle.scalariform.MethodLengthChecker" level="warning"> <parameters> <parameter name="maxLength">50</parameter> </parameters> </check>
- id - method.name
- description - Check that method names match a regular expression
- class - org.scalastyle.scalariform.MethodNamesChecker
- default level - WarningLevel
The Scala style guide recommends that method names conform to certain standards. If the methods are overriding another method, and the overridden method cannot be changed, then use the ignoreOverride parameter.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string | ^[a-z][A-Za-z0-9]*(_=)?$ |
| ignoreRegex | Regular expression to ignore | string | ^$ |
| ignoreOverride | Ignore override | boolean | false |
<check enabled="true" class="org.scalastyle.scalariform.MethodNamesChecker" level="warning"> <parameters> <parameter name="regex">^[A-Za-z]*$</parameter> <parameter name="ignoreRegex">^.*$</parameter> <parameter name="ignoreOverride">false</parameter> </parameters> </check>
org.scalastyle.scalariform.MultipleStringLiteralsChecker - Checks that a string literal does not appear multiple times
- id - multiple.string.literals
- description - Checks that a string literal does not appear multiple times
- class - org.scalastyle.scalariform.MultipleStringLiteralsChecker
- default level - WarningLevel
Code duplication makes maintenance more difficult, so it can be better to replace the multiple occurrences with a constant.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| allowed | Maximum occurences allowed | integer | 1 |
| ignoreRegex | Ignore regular expression | string | ^""$ |
<check enabled="true" class="org.scalastyle.scalariform.MultipleStringLiteralsChecker" level="warning"> <parameters> <parameter name="allowed">1</parameter> <parameter name="ignoreRegex">^\"\"$</parameter> </parameters> </check>
org.scalastyle.scalariform.NoCloneChecker - Check that classes and objects do not define the clone() method
- id - no.clone
- description - Check that classes and objects do not define the clone() method
- class - org.scalastyle.scalariform.NoCloneChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.NoFinalizeChecker - Check that classes and objects do not define the finalize() method
- id - no.finalize
- description - Check that classes and objects do not define the finalize() method
- class - org.scalastyle.scalariform.NoFinalizeChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker - No whitespace after left bracket '['
- id - no.whitespace.after.left.bracket
- description - No whitespace after left bracket '['
- class - org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker - No whitespace before left bracket '['
- id - no.whitespace.before.left.bracket
- description - No whitespace before left bracket '['
- class - org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.NotImplementedErrorUsage - Checks that the code does not have ??? operators.
- id - not.implemented.error.usage
- description - Checks that the code does not have ??? operators.
- class - org.scalastyle.scalariform.NotImplementedErrorUsage
- default level - WarningLevel
The ??? operator denotes that an implementation is missing. This rule helps to avoid potential runtime errors because of not implemented code.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.NotImplementedErrorUsage" level="warning"/>
- id - null
- description - Check that null is not used
- class - org.scalastyle.scalariform.NullChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.NumberOfMethodsInTypeChecker - Check that a class / trait / object does not have too many methods
- id - number.of.methods
- description - Check that a class / trait / object does not have too many methods
- class - org.scalastyle.scalariform.NumberOfMethodsInTypeChecker
- default level - WarningLevel
If a type declares too many methods, this can be an indication of bad design.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maxMethods | Maximum methods | integer | 30 |
<check enabled="true" class="org.scalastyle.scalariform.NumberOfMethodsInTypeChecker" level="warning"> <parameters> <parameter name="maxMethods">30</parameter> </parameters> </check>
org.scalastyle.scalariform.NumberOfTypesChecker - Checks that there are not too many types declared in a file
- id - number.of.types
- description - Checks that there are not too many types declared in a file
- class - org.scalastyle.scalariform.NumberOfTypesChecker
- default level - WarningLevel
If there are too many classes/objects defined in a single file, this can cause the code to be difficult to understand.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maxTypes | Maximum Number | integer | 20 |
<check enabled="true" class="org.scalastyle.scalariform.NumberOfTypesChecker" level="warning"> <parameters> <parameter name="maxTypes">20</parameter> </parameters> </check>
- id - object.name
- description - Check that object names match a regular expression
- class - org.scalastyle.scalariform.ObjectNamesChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string | ^[A-Z][A-Za-z]*$ |
TBD
org.scalastyle.scalariform.PackageObjectNamesChecker - Check that package object names match a regular expression
- id - package.object.name
- description - Check that package object names match a regular expression
- class - org.scalastyle.scalariform.PackageObjectNamesChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string | ^[a-z][A-Za-z]*$ |
TBD
- id - parameter.number
- description - Maximum number of parameters for a method
- class - org.scalastyle.scalariform.ParameterNumberChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| maxParameters | Maximum Number | integer | 8 |
TBD
org.scalastyle.scalariform.PublicMethodsHaveTypeChecker - Check that a method has an explicit return type, it is not inferred
- id - public.methods.have.type
- description - Check that a method has an explicit return type, it is not inferred
- class - org.scalastyle.scalariform.PublicMethodsHaveTypeChecker
- default level - WarningLevel
A public method declared on a type is effectively an API declaration. Explicitly declaring a return type means that other code which depends on that type won't break unexpectedly.
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| ignoreOverride | Ignore overridden methods | boolean | false |
<check enabled="true" class="org.scalastyle.scalariform.PublicMethodsHaveTypeChecker" level="warning"> <parameters> <parameter name="ignoreOverride">false</parameter> </parameters> </check>
org.scalastyle.scalariform.RedundantIfChecker - Checks that if expressions are not redundant, i.e. easily replaced by a variant of the condition
- id - if.redundant
- description - Checks that if expressions are not redundant, i.e. easily replaced by a variant of the condition
- class - org.scalastyle.scalariform.RedundantIfChecker
- default level - WarningLevel
If expressions with boolean constants in both branches can be eliminated without affecting readability. Prefer simply cond to if (cond) true else false and !cond to if (cond) false else true.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.RedundantIfChecker" level="warning"/>
- id - return
- description - Check that return is not used
- class - org.scalastyle.scalariform.ReturnChecker
- default level - WarningLevel
No parameters
TBD
- id - simplify.boolean.expression
- description - Boolean expression can be simplified
- class - org.scalastyle.scalariform.SimplifyBooleanExpressionChecker
- default level - WarningLevel
No parameters
TBD
- id - spaces.after.plus
- description - Check that the plus sign is followed by a space
- class - org.scalastyle.scalariform.SpacesAfterPlusChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.SpacesBeforePlusChecker - Check that the plus sign is preceded by a space
- id - spaces.before.plus
- description - Check that the plus sign is preceded by a space
- class - org.scalastyle.scalariform.SpacesBeforePlusChecker
- default level - WarningLevel
No parameters
TBD
- id - structural.type
- description - Check that structural types are not used.
- class - org.scalastyle.scalariform.StructuralTypeChecker
- default level - WarningLevel
No parameters
TBD
org.scalastyle.scalariform.TokenChecker - Checks that a regular expression cannot be matched in a token, if found reports this
- id - token
- description - Checks that a regular expression cannot be matched in a token, if found reports this
- class - org.scalastyle.scalariform.TokenChecker
- default level - WarningLevel
| Parameter | Description | Type | Default Value |
|---|---|---|---|
| regex | Regular expression | string | ^$ |
<check enabled="true" class="org.scalastyle.scalariform.TokenChecker" level="warning"> <parameters> <parameter name="regex">^[ai]sInstanceOf$</parameter> </parameters> <customMessage>Avoid casting.</customMessage> </check>
- id - underscore.import
- description - Avoid wildcard imports
- class - org.scalastyle.scalariform.UnderscoreImportChecker
- default level - WarningLevel
Importing all classes from a package or static members from a class leads to tight coupling between packages or classes and might lead to problems when a new version of a library introduces name clashes.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.UnderscoreImportChecker" level="warning"/>
org.scalastyle.scalariform.UppercaseLChecker - Checks that if a long literal is used, then an uppercase L is used
- id - uppercase.l
- description - Checks that if a long literal is used, then an uppercase L is used
- class - org.scalastyle.scalariform.UppercaseLChecker
- default level - WarningLevel
A lowercase L (l) can look similar to a number 1 with some fonts.
No parameters
<check enabled="true" class="org.scalastyle.scalariform.UppercaseLChecker" level="warning"/>
org.scalastyle.scalariform.VarFieldChecker - Checks that classes and objects do not define mutable fields
- id - var.field
- description - Checks that classes and objects do not define mutable fields
- class - org.scalastyle.scalariform.VarFieldChecker
- default level - WarningLevel
var (mutable fields) are deprecated if you're using a strict functional style
No parameters
<check enabled="true" class="org.scalastyle.scalariform.VarFieldChecker" level="warning"/>
- id - var.local
- description - Checks that functions do not define mutable variables
- class - org.scalastyle.scalariform.VarLocalChecker
- default level - WarningLevel
vars (mutable local variables) loops are deprecated if you're using a strict functional style
No parameters
<check enabled="true" class="org.scalastyle.scalariform.VarLocalChecker" level="warning"/>
- id - while
- description - Checks that while is not used
- class - org.scalastyle.scalariform.WhileChecker
- default level - WarningLevel
while loops are deprecated if you're using a strict functional style
No parameters
<check enabled="true" class="org.scalastyle.scalariform.WhileChecker" level="warning"/>