AnnotationUseStyleCheck (checkstyle 9.3 API)

java.lang.Object
- com.puppycrawl.tools.checkstyle.api.AutomaticBean
- - com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
  - - com.puppycrawl.tools.checkstyle.api.AbstractCheck
    - - com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck

All Implemented Interfaces:

Configurable, Contextualizable
```
public final class AnnotationUseStyleCheck
extends AbstractCheck
```
Checks the style of elements in annotations.

Annotations have three element styles starting with the least verbose.
- ElementStyleOption.COMPACT_NO_ARRAY
- ElementStyleOption.COMPACT
- ElementStyleOption.EXPANDED
To not enforce an element style a ElementStyleOption.IGNORE type is provided. The desired style can be set through the elementStyle property.

Using the ElementStyleOption.EXPANDED style is more verbose. The expanded version is sometimes referred to as "named parameters" in other languages.

Using the ElementStyleOption.COMPACT style is less verbose. This style can only be used when there is an element called 'value' which is either the sole element or all other elements have default values.

Using the ElementStyleOption.COMPACT_NO_ARRAY style is less verbose. It is similar to the ElementStyleOption.COMPACT style but single value arrays are flagged. With annotations a single value array does not need to be placed in an array initializer.

The ending parenthesis are optional when using annotations with no elements. To always require ending parenthesis use the ClosingParensOption.ALWAYS type. To never have ending parenthesis use the ClosingParensOption.NEVER type. To not enforce a closing parenthesis preference a ClosingParensOption.IGNORE type is provided. Set this through the closingParens property.

Annotations also allow you to specify arrays of elements in a standard format. As with normal arrays, a trailing comma is optional. To always require a trailing comma use the TrailingArrayCommaOption.ALWAYS type. To never have a trailing comma use the TrailingArrayCommaOption.NEVER type. To not enforce a trailing array comma preference a TrailingArrayCommaOption.IGNORE type is provided. Set this through the trailingArrayComma property.

By default the ElementStyleOption is set to COMPACT_NO_ARRAY, the TrailingArrayCommaOption is set to NEVER, and the ClosingParensOption is set to NEVER.

According to the JLS, it is legal to include a trailing comma in arrays used in annotations but Sun's Java 5 & 6 compilers will not compile with this syntax. This may in be a bug in Sun's compilers since eclipse 3.4's built-in compiler does allow this syntax as defined in the JLS. Note: this was tested with compilers included with JDK versions 1.5.0.17 and 1.6.0.11 and the compiler included with eclipse 3.4.1.

See Java Language specification, §9.7.
- Property elementStyle - Define the annotation element styles. Type is com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck$ElementStyleOption. Default value is compact_no_array.
- Property closingParens - Define the policy for ending parenthesis. Type is com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck$ClosingParensOption. Default value is never.
- Property trailingArrayComma - Define the policy for trailing comma in arrays. Type is com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck$TrailingArrayCommaOption. Default value is never.
To configure the check:
```
 <module name="AnnotationUseStyle"/>
 
```
Example:
```
 @Deprecated // OK
 @SomeArrays(pooches={DOGS.LEO}) // Violation - COMPACT_NO_ARRAY
 @SuppressWarnings({""}) // Violation - COMPACT_NO_ARRAY
 public class TestOne
 {

 }

 @SomeArrays(pooches={DOGS.LEO}, um={}, test={"bleh"}) // Violation - COMPACT_NO_ARRAY
 @SuppressWarnings("") // OK
 @Deprecated() // Violation - cannot have closing parenthesis
 class TestTwo {

 }
 
```
To configure the check to enforce an expanded style, with a trailing array comma set to never and always including the closing parenthesis.
```
 <module name="AnnotationUseStyle">
   <property name="elementStyle" value="expanded"/>
   <property name="trailingArrayComma" value="never"/>
   <property name="closingParens" value="always"/>
 </module>
 
```
Example:
```
 @Deprecated // Violation - must have closing parenthesis
 @SomeArrays(pooches={DOGS.LEO}) // OK
 @SuppressWarnings({""}) // Violation - EXPANDED
 public class TestOne
 {

 }

 @SomeArrays(pooches={DOGS.LEO}, um={}, test={"bleh"}) // OK
 @SuppressWarnings("") // Violation - EXPANDED
 @Deprecated() // OK
 class TestTwo {

 }
 
```
Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:
- annotation.incorrect.style
- annotation.parens.missing
- annotation.parens.present
- annotation.trailing.comma.missing
- annotation.trailing.comma.present
Since:

5.0

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`AnnotationUseStyleCheck.ClosingParensOption` Defines the two styles for defining elements in an annotation.
`static class`	`AnnotationUseStyleCheck.ElementStyleOption` Defines the styles for defining elements in an annotation.
`static class`	`AnnotationUseStyleCheck.TrailingArrayCommaOption` Defines the two styles for defining elements in an annotation.

Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
AutomaticBean.OutputStreamOptions

Field Summary

Fields
Modifier and Type	Field and Description
`private static java.lang.String`	`ANNOTATION_ELEMENT_SINGLE_NAME` The element name used to receive special linguistic support for annotation use.
`private AnnotationUseStyleCheck.ClosingParensOption`	`closingParens` Define the policy for ending parenthesis.
`private AnnotationUseStyleCheck.ElementStyleOption`	`elementStyle` Define the annotation element styles.
`static java.lang.String`	`MSG_KEY_ANNOTATION_INCORRECT_STYLE` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_ANNOTATION_PARENS_MISSING` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_ANNOTATION_PARENS_PRESENT` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING` A key is pointing to the warning message text in "messages.properties" file.
`static java.lang.String`	`MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT` A key is pointing to the warning message text in "messages.properties" file.
`private AnnotationUseStyleCheck.TrailingArrayCommaOption`	`trailingArrayComma` Define the policy for trailing comma in arrays.

Constructor Summary

Constructors
Constructor and Description

AnnotationUseStyleCheck()

Constructors
Constructor and Description
`AnnotationUseStyleCheck()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`private void`	`checkCheckClosingParensOption(DetailAST ast)` Checks to see if the closing parenthesis are present if required or prohibited.
`private void`	`checkCompactNoArrayStyle(DetailAST annotation)` Checks for compact no array style type violations.
`private void`	`checkCompactStyle(DetailAST annotation)` Checks for compact style type violations.
`private void`	`checkExpandedStyle(DetailAST annotation)` Checks for expanded style type violations.
`private void`	`checkStyleType(DetailAST annotation)` Checks to see if the `AnnotationElementStyleOption` is correct.
`private void`	`checkTrailingComma(DetailAST annotation)` Checks to see if the trailing comma is present if required or prohibited.
`int[]`	`getAcceptableTokens()` The configurable token set.
`int[]`	`getDefaultTokens()` Returns the default token a check is interested in.
`private static <T extends java.lang.Enum<T>> T`	`getOption(java.lang.Class<T> enumClass, java.lang.String value)` Retrieves an `Enum` type from a @{link String String}.
`int[]`	`getRequiredTokens()` The tokens that this check must be registered for.
`private static boolean`	`hasArguments(DetailAST annotation)` Checks that annotation has arguments.
`private void`	`logCommaViolation(DetailAST ast)` Logs a trailing array comma violation if one exists.
`void`	`setClosingParens(java.lang.String parens)` Setter to define the policy for ending parenthesis.
`void`	`setElementStyle(java.lang.String style)` Setter to define the annotation element styles.
`void`	`setTrailingArrayComma(java.lang.String comma)` Setter to define the policy for trailing comma in arrays.
`void`	`visitToken(DetailAST ast)` Called to process a token.

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearViolations, destroy, finishTree, getFileContents, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, leaveToken, log, log, log, setFileContents, setTabWidth, setTokens

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
finishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverity

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
configure, contextualize, getConfiguration, setupChild

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - MSG_KEY_ANNOTATION_INCORRECT_STYLE
```
public static final java.lang.String MSG_KEY_ANNOTATION_INCORRECT_STYLE
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_ANNOTATION_PARENS_MISSING
```
public static final java.lang.String MSG_KEY_ANNOTATION_PARENS_MISSING
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_ANNOTATION_PARENS_PRESENT
```
public static final java.lang.String MSG_KEY_ANNOTATION_PARENS_PRESENT
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING
```
public static final java.lang.String MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT
```
public static final java.lang.String MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT
```
    A key is pointing to the warning message text in "messages.properties" file.
    
    See Also:
    
    Constant Field Values
  - ANNOTATION_ELEMENT_SINGLE_NAME
```
private static final java.lang.String ANNOTATION_ELEMENT_SINGLE_NAME
```
    The element name used to receive special linguistic support for annotation use.
    
    See Also:
    
    Constant Field Values
  - elementStyle
```
private AnnotationUseStyleCheck.ElementStyleOption elementStyle
```
    Define the annotation element styles.
  - trailingArrayComma
```
private AnnotationUseStyleCheck.TrailingArrayCommaOption trailingArrayComma
```
    Define the policy for trailing comma in arrays.
  - closingParens
```
private AnnotationUseStyleCheck.ClosingParensOption closingParens
```
    Define the policy for ending parenthesis.
- Constructor Detail
  - AnnotationUseStyleCheck
```
public AnnotationUseStyleCheck()
```
- Method Detail
  - setElementStyle
```
public void setElementStyle(java.lang.String style)
```
    Setter to define the annotation element styles.
    
    Parameters:
    
    style - string representation
  - setTrailingArrayComma
```
public void setTrailingArrayComma(java.lang.String comma)
```
    Setter to define the policy for trailing comma in arrays.
    
    Parameters:
    
    comma - string representation
  - setClosingParens
```
public void setClosingParens(java.lang.String parens)
```
    Setter to define the policy for ending parenthesis.
    
    Parameters:
    
    parens - string representation
  - getOption
```
private static <T extends java.lang.Enum<T>> T getOption(java.lang.Class<T> enumClass,
                                                         java.lang.String value)
```
    Retrieves an Enum type from a @{link String String}.
    
    Type Parameters:
    
    T - the enum type
    
    Parameters:
    
    enumClass - the enum class
    
    value - the string representing the enum
    
    Returns:
    
    the enum type
    
    Throws:
    
    java.lang.IllegalArgumentException - when unable to parse value
  - getDefaultTokens
```
public int[] getDefaultTokens()
```
    Description copied from class: AbstractCheck
    
    Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.
    
    Specified by:
    
    getDefaultTokens in class AbstractCheck
    
    Returns:
    
    the default tokens
    
    See Also:
    
    TokenTypes
  - getRequiredTokens
```
public int[] getRequiredTokens()
```
    Description copied from class: AbstractCheck
    
    The tokens that this check must be registered for.
    
    Specified by:
    
    getRequiredTokens in class AbstractCheck
    
    Returns:
    
    the token set this must be registered for.
    
    See Also:
    
    TokenTypes
  - getAcceptableTokens
```
public int[] getAcceptableTokens()
```
    Description copied from class: AbstractCheck
    
    The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.
    
    Specified by:
    
    getAcceptableTokens in class AbstractCheck
    
    Returns:
    
    the token set this check is designed for.
    
    See Also:
    
    TokenTypes
  - visitToken
```
public void visitToken(DetailAST ast)
```
    Description copied from class: AbstractCheck
    
    Called to process a token.
    
    Overrides:
    
    visitToken in class AbstractCheck
    
    Parameters:
    
    ast - the token to process
  - checkStyleType
```
private void checkStyleType(DetailAST annotation)
```
    Checks to see if the AnnotationElementStyleOption is correct.
    
    Parameters:
    
    annotation - the annotation token
  - checkExpandedStyle
```
private void checkExpandedStyle(DetailAST annotation)
```
    Checks for expanded style type violations.
    
    Parameters:
    
    annotation - the annotation token
  - hasArguments
```
private static boolean hasArguments(DetailAST annotation)
```
    Checks that annotation has arguments.
    
    Parameters:
    
    annotation - to check
    
    Returns:
    
    true if annotation has arguments, false otherwise
  - checkCompactStyle
```
private void checkCompactStyle(DetailAST annotation)
```
    Checks for compact style type violations.
    
    Parameters:
    
    annotation - the annotation token
  - checkCompactNoArrayStyle
```
private void checkCompactNoArrayStyle(DetailAST annotation)
```
    Checks for compact no array style type violations.
    
    Parameters:
    
    annotation - the annotation token
  - checkTrailingComma
```
private void checkTrailingComma(DetailAST annotation)
```
    Checks to see if the trailing comma is present if required or prohibited.
    
    Parameters:
    
    annotation - the annotation token
  - logCommaViolation
```
private void logCommaViolation(DetailAST ast)
```
    Logs a trailing array comma violation if one exists.
    
    Parameters:
    
    ast - the array init ANNOTATION_ARRAY_INIT.
  - checkCheckClosingParensOption
```
private void checkCheckClosingParensOption(DetailAST ast)
```
    Checks to see if the closing parenthesis are present if required or prohibited.
    
    Parameters:
    
    ast - the annotation token

Class AnnotationUseStyleCheck

Nested Class Summary

Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean

Field Summary

Constructor Summary

Method Summary

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

Methods inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean

Methods inherited from class java.lang.Object

Field Detail

MSG_KEY_ANNOTATION_INCORRECT_STYLE

MSG_KEY_ANNOTATION_PARENS_MISSING

MSG_KEY_ANNOTATION_PARENS_PRESENT

MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING

MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT

ANNOTATION_ELEMENT_SINGLE_NAME

elementStyle

trailingArrayComma

closingParens

Constructor Detail

AnnotationUseStyleCheck

Method Detail

setElementStyle

setTrailingArrayComma

setClosingParens

getOption

getDefaultTokens

getRequiredTokens

getAcceptableTokens

visitToken

checkStyleType

checkExpandedStyle

hasArguments

checkCompactStyle

checkCompactNoArrayStyle

checkTrailingComma

logCommaViolation

checkCheckClosingParensOption