java.lang.Object
- com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
- - 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 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.
- Property ignoreStringsRegexp - Specify RegExp for ignored strings (with quotation marks). Type is java.util.regex.Pattern. Default value is "^""$".
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.AbstractAutomaticBean
  AbstractAutomaticBean.OutputStreamOptions

Field Summary

Fields
Modifier and Type	Field	Description
`private static 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 BitSet`	`ignoreOccurrenceContext`	Specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp.
`private Pattern`	`ignoreStringsRegexp`	Specify RegExp for ignored strings (with quotation marks).
`static String`	`MSG_KEY`	A key is pointing to the warning message text in "messages.properties" file.
`private static String`	`QUOTE`	String used to amend TEXT_BLOCK_CONTENT so that it matches STRING_LITERAL.
`private Map<String,List<DetailAST>>`	`stringMap`	The found strings and their tokens.

Constructor Summary

Constructors
Constructor Description

MultipleStringLiteralsCheck()
Construct an instance with default values.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	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(String... strRep)`	Setter to specify token type names where duplicate strings are ignored even if they don't match ignoredStringsRegexp.
`void`	`setIgnoreStringsRegexp(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, getFilePath, 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.AbstractAutomaticBean
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 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 Pattern ALL_NEW_LINES
```
    Compiled pattern for all system newlines.
  - QUOTE
```
private static final String QUOTE
```
    String used to amend TEXT_BLOCK_CONTENT so that it matches STRING_LITERAL.
    
    See Also:
    
    Constant Field Values
  - stringMap
```
private final Map<String,List<DetailAST>> stringMap
```
    The found strings and their tokens.
  - ignoreOccurrenceContext
```
private final 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 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.
    
    Since:
    
    3.5
  - setIgnoreStringsRegexp
```
public final void setIgnoreStringsRegexp(Pattern ignoreStringsRegexp)
```
    Setter to specify RegExp for ignored strings (with quotation marks).
    
    Parameters:
    
    ignoreStringsRegexp - regular expression pattern for ignored strings
    
    Since:
    
    4.0
  - setIgnoreOccurrenceContext
```
public final void setIgnoreOccurrenceContext(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
    
    Since:
    
    4.4
  - 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

Class MultipleStringLiteralsCheck

Nested Class Summary

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

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.AbstractAutomaticBean

Methods inherited from class java.lang.Object

Field Detail

MSG_KEY

ALL_NEW_LINES

QUOTE

stringMap

ignoreOccurrenceContext

allowedDuplicates

ignoreStringsRegexp

Constructor Detail

MultipleStringLiteralsCheck

Method Detail

setAllowedDuplicates

setIgnoreStringsRegexp

setIgnoreOccurrenceContext

getDefaultTokens

getAcceptableTokens

getRequiredTokens

visitToken

isInIgnoreOccurrenceContext

beginTree

finishTree