com.puppycrawl.tools.checkstyle.checks.coding

Class MultipleStringLiteralsCheck

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.coding.MultipleStringLiteralsCheck

All Implemented Interfaces:

Configurable, Contextualizable

public class MultipleStringLiteralsCheck
extends AbstractCheck

Checks for multiple occurrences of the same string literal within a single file.

Rationale: Code duplication makes maintenance more difficult, so it can be better to replace the multiple occurrences with a constant.

• Property allowedDuplicates - Specify the maximum number of occurrences to allow without generating a warning. Type is int. Default value is 1.
• Property ignoreStringsRegexp - Specify RegExp for ignored strings (with quotation marks). Type is java.util.regex.Pattern. Default value is "^""$".
• Property ignoreOccurrenceContext - Specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp. This allows you to exclude syntactical contexts like annotations or static initializers from the check. Type is java.lang.String[]. Validation type is tokenTypesSet. Default value is ANNOTATION.

To configure the check:

 <module name="MultipleStringLiterals"/>
 

To configure the check so that it allows two occurrences of each string:

 <module name="MultipleStringLiterals">
   <property name="allowedDuplicates" value="2"/>
 </module>
 

To configure the check so that it ignores ", " and empty strings:

 <module name="MultipleStringLiterals">
   <property name="ignoreStringsRegexp"
     value='^(("")|(", "))$'/>
 </module>
 

To configure the check so that it flags duplicate strings in all syntactical contexts, even in annotations like @SuppressWarnings("unchecked"):

 <module name="MultipleStringLiterals">
   <property name="ignoreOccurrenceContext" value=""/>
 </module>
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

• multiple.string.literal

Since:

3.5

Nested Class Summary

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.util.regex.Pattern	ALL_NEW_LINES Compiled pattern for all system newlines.
private int	allowedDuplicates Specify the maximum number of occurrences to allow without generating a warning.
private java.util.BitSet	ignoreOccurrenceContext Specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp.
private java.util.regex.Pattern	ignoreStringsRegexp Specify RegExp for ignored strings (with quotation marks).
static java.lang.String	MSG_KEY A key is pointing to the warning message text in "messages.properties" file.
private static java.lang.String	QUOTE String used to amend TEXT_BLOCK_CONTENT so that it matches STRING_LITERAL.
private java.util.Map<java.lang.String,java.util.List<DetailAST>>	stringMap The found strings and their tokens.

Constructor Summary

Constructors

Constructor and Description
MultipleStringLiteralsCheck() Construct an instance with default values.

Method Summary

Modifier and Type	Method and Description
void	beginTree(DetailAST rootAST) Called before the starting to process a tree.
void	finishTree(DetailAST rootAST) Called after finished processing a tree.
int[]	getAcceptableTokens() The configurable token set.
int[]	getDefaultTokens() Returns the default token a check is interested in.
int[]	getRequiredTokens() The tokens that this check must be registered for.
private boolean	isInIgnoreOccurrenceContext(DetailAST ast) Analyses the path from the AST root to a given AST for occurrences of the token types in ignoreOccurrenceContext.
void	setAllowedDuplicates(int allowedDuplicates) Setter to specify the maximum number of occurrences to allow without generating a warning.
void	setIgnoreOccurrenceContext(java.lang.String... strRep) Setter to specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp.
void	setIgnoreStringsRegexp(java.util.regex.Pattern ignoreStringsRegexp) Setter to specify RegExp for ignored strings (with quotation marks).
void	visitToken(DetailAST ast) Called to process a token.

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

clearViolations, destroy, 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

public static final java.lang.String MSG_KEY

A key is pointing to the warning message text in "messages.properties" file.

See Also:

Constant Field Values

ALL_NEW_LINES

private static final java.util.regex.Pattern ALL_NEW_LINES

Compiled pattern for all system newlines.

QUOTE

private static final java.lang.String QUOTE

String used to amend TEXT_BLOCK_CONTENT so that it matches STRING_LITERAL.

See Also:

Constant Field Values

stringMap

private final java.util.Map<java.lang.String,java.util.List<DetailAST>> stringMap

The found strings and their tokens.

ignoreOccurrenceContext

private final java.util.BitSet ignoreOccurrenceContext

Specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp. This allows you to exclude syntactical contexts like annotations or static initializers from the check.

allowedDuplicates

private int allowedDuplicates

Specify the maximum number of occurrences to allow without generating a warning.

ignoreStringsRegexp

private java.util.regex.Pattern ignoreStringsRegexp

Specify RegExp for ignored strings (with quotation marks).

Constructor Detail

MultipleStringLiteralsCheck

public MultipleStringLiteralsCheck()

Construct an instance with default values.

Method Detail

setAllowedDuplicates

public void setAllowedDuplicates(int allowedDuplicates)

Setter to specify the maximum number of occurrences to allow without generating a warning.

Parameters:

allowedDuplicates - The maximum number of duplicates.

setIgnoreStringsRegexp

public final void setIgnoreStringsRegexp(java.util.regex.Pattern ignoreStringsRegexp)

Setter to specify RegExp for ignored strings (with quotation marks).

Parameters:

ignoreStringsRegexp - regular expression pattern for ignored strings

setIgnoreOccurrenceContext

public final void setIgnoreOccurrenceContext(java.lang.String... strRep)

Setter to specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp. This allows you to exclude syntactical contexts like annotations or static initializers from the check.

Parameters:

strRep - the string representation of the tokens interested in

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

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

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

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

isInIgnoreOccurrenceContext

private boolean isInIgnoreOccurrenceContext(DetailAST ast)

Analyses the path from the AST root to a given AST for occurrences of the token types in ignoreOccurrenceContext.

Parameters:

ast - the node from where to start searching towards the root node

Returns:

whether the path from the root node to ast contains one of the token type in ignoreOccurrenceContext.

beginTree

public void beginTree(DetailAST rootAST)

Description copied from class: AbstractCheck

Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.

Overrides:

beginTree in class AbstractCheck

Parameters:

rootAST - the root of the tree

finishTree

public void finishTree(DetailAST rootAST)

Description copied from class: AbstractCheck

Called after finished processing a tree. Ideal place to report on information collected whilst processing a tree.

Overrides:

finishTree in class AbstractCheck

Parameters:

rootAST - the root of the tree