Class OneStatementPerLineCheck
- java.lang.Object
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- com.puppycrawl.tools.checkstyle.api.AutomaticBean
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- com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
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- com.puppycrawl.tools.checkstyle.api.AbstractCheck
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- com.puppycrawl.tools.checkstyle.checks.coding.OneStatementPerLineCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public final class OneStatementPerLineCheck extends AbstractCheck
Restricts the number of statements per line to one.Rationale: It's very difficult to read multiple statements on one line.
In the Java programming language, statements are the fundamental unit of execution. All statements except blocks are terminated by a semicolon. Blocks are denoted by open and close curly braces.
OneStatementPerLineCheck checks the following types of statements: variable declaration statements, empty statements, assignment statements, expression statements, increment statements, object creation statements, 'for loop' statements, 'break' statements, 'continue' statements, 'return' statements, import statements.
The following examples will be flagged as a violation:
//Each line causes violation: int var1; int var2; var1 = 1; var2 = 2; int var1 = 1; int var2 = 2; var1++; var2++; Object obj1 = new Object(); Object obj2 = new Object(); import java.io.EOFException; import java.io.BufferedReader; ;; //two empty statements on the same line. //Multi-line statements: int var1 = 1 ; var2 = 2; //violation here int o = 1, p = 2, r = 5; int t; //violation here
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Field Summary
Fields Modifier and Type Field Description private java.util.Deque<java.lang.Integer>
countOfSemiInLambda
Counts number of semicolons in nested lambdas.private int
forStatementEnd
Hold the line-number where the last 'for-loop' statement ended.private boolean
inForHeader
The for-header usually has 3 statements on one line, but THIS IS OK.private boolean
isInLambda
Holds if current token is inside lambda.private int
lambdaStatementEnd
Hold the line-number where the last lambda statement ended.private int
lastStatementEnd
Hold the line-number where the last statement ended.static java.lang.String
MSG_KEY
A key is pointing to the warning message text in "messages.properties" file.
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Constructor Summary
Constructors Constructor Description OneStatementPerLineCheck()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
beginTree(DetailAST rootAST)
Called before the starting to process a tree.private void
checkIfSemicolonIsInDifferentLineThanPrevious(DetailAST ast)
Checks if given semicolon is in different line than previous.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 static boolean
isMultilineStatement(DetailAST ast)
Checks whether statement is multiline.private static boolean
isOnTheSameLine(DetailAST ast, int lastStatementEnd, int forStatementEnd, int lambdaStatementEnd)
Checks whether two statements are on the same line.void
leaveToken(DetailAST ast)
Called after all the child nodes have been process.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, isCommentNodesRequired, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, log, setId, setSeverity
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Methods inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
configure, contextualize, finishLocalSetup, getConfiguration, setupChild
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Field Detail
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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
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countOfSemiInLambda
private final java.util.Deque<java.lang.Integer> countOfSemiInLambda
Counts number of semicolons in nested lambdas.
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lastStatementEnd
private int lastStatementEnd
Hold the line-number where the last statement ended.
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forStatementEnd
private int forStatementEnd
Hold the line-number where the last 'for-loop' statement ended.
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inForHeader
private boolean inForHeader
The for-header usually has 3 statements on one line, but THIS IS OK.
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isInLambda
private boolean isInLambda
Holds if current token is inside lambda.
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lambdaStatementEnd
private int lambdaStatementEnd
Hold the line-number where the last lambda statement ended.
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Method Detail
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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 classAbstractCheck
- Returns:
- the default tokens
- See Also:
TokenTypes
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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 classAbstractCheck
- Returns:
- the token set this check is designed for.
- See Also:
TokenTypes
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getRequiredTokens
public int[] getRequiredTokens()
Description copied from class:AbstractCheck
The tokens that this check must be registered for.- Specified by:
getRequiredTokens
in classAbstractCheck
- Returns:
- the token set this must be registered for.
- See Also:
TokenTypes
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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 classAbstractCheck
- Parameters:
rootAST
- the root of the tree
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visitToken
public void visitToken(DetailAST ast)
Description copied from class:AbstractCheck
Called to process a token.- Overrides:
visitToken
in classAbstractCheck
- Parameters:
ast
- the token to process
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leaveToken
public void leaveToken(DetailAST ast)
Description copied from class:AbstractCheck
Called after all the child nodes have been process.- Overrides:
leaveToken
in classAbstractCheck
- Parameters:
ast
- the token leaving
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checkIfSemicolonIsInDifferentLineThanPrevious
private void checkIfSemicolonIsInDifferentLineThanPrevious(DetailAST ast)
Checks if given semicolon is in different line than previous.- Parameters:
ast
- semicolon to check
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isOnTheSameLine
private static boolean isOnTheSameLine(DetailAST ast, int lastStatementEnd, int forStatementEnd, int lambdaStatementEnd)
Checks whether two statements are on the same line.- Parameters:
ast
- token for the current statement.lastStatementEnd
- the line-number where the last statement ended.forStatementEnd
- the line-number where the last 'for-loop' statement ended.lambdaStatementEnd
- the line-number where the last lambda statement ended.- Returns:
- true if two statements are on the same line.
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isMultilineStatement
private static boolean isMultilineStatement(DetailAST ast)
Checks whether statement is multiline.- Parameters:
ast
- token for the current statement.- Returns:
- true if one statement is distributed over two or more lines.
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