Class GenericWhitespaceCheck
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.whitespace.GenericWhitespaceCheck
- All Implemented Interfaces:
Configurable
,Contextualizable
Checks that the whitespace around the Generic tokens (angle brackets) "<" and ">" are correct to the typical convention. The convention is not configurable.
Left angle bracket ("<"):
- should be preceded with whitespace only in generic methods definitions.
- should not be preceded with whitespace when it is precede method name or constructor.
- should not be preceded with whitespace when following type name.
- should not be followed with whitespace in all cases.
Right angle bracket (">"):
- should not be preceded with whitespace in all cases.
- should be followed with whitespace in almost all cases, except diamond operators and when preceding method name or constructor.
To configure the check:
<module name="GenericWhitespace"/>
Examples with correct spacing:
// Generic methods definitions public void <K, V extends Number> boolean foo(K, V) {} // Generic type definition class name<T1, T2, ..., Tn> {} // Generic type reference OrderedPair<String, Box<Integer>> p; // Generic preceded method name boolean same = Util.<Integer, String>compare(p1, p2); // Diamond operator Pair<Integer, String> p1 = new Pair<>(1, "apple"); // Method reference List<T> list = ImmutableList.Builder<T>::new; // Method reference sort(list, Comparable::<String>compareTo); // Constructor call MyClass obj = new <String>MyClass();
Examples with incorrect spacing:
List< String> l; // violation, "<" followed by whitespace Box b = Box. <String>of("foo"); // violation, "<" preceded with whitespace public<T> void foo() {} // violation, "<" not preceded with whitespace List a = new ArrayList<> (); // violation, ">" followed by whitespace Map<Integer, String>m; // violation, ">" not followed by whitespace Pair<Integer, Integer > p; // violation, ">" preceded with whitespace
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
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ws.followed
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ws.illegalFollow
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ws.notPreceded
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ws.preceded
- Since:
- 5.0
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Nested Class Summary
Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.api.AutomaticBean
AutomaticBean.OutputStreamOptions
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final String
Close angle bracket literal.private int
Used to count the depth of a Generic expression.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.static final String
A key is pointing to the warning message text in "messages.properties" file.private static final String
Open angle bracket literal. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
Called before the starting to process a tree.private static boolean
containsWhitespaceBefore
(int before, String line) Returns whether the specified string contains only whitespace up to specified index.private static boolean
containsWhitespaceBetween
(int fromIndex, int toIndex, String line) Returns whether the specified string contains only whitespace between specified indices.int[]
The configurable token set.int[]
Returns the default token a check is interested in.int[]
The tokens that this check must be registered for.private static boolean
isAfterMethodReference
(DetailAST genericEnd) Checks if current generic end ('>') is located aftermethod reference operator
.private static boolean
isCharacterValidAfterGenericEnd
(char charAfter) Checks whether given character is valid to be right after generic ends.private static boolean
Checks if generic is before constructor invocation.private static boolean
Is generic before method reference.private void
processEnd
(DetailAST ast) Checks the token for the end of Generics.private void
processNestedGenerics
(DetailAST ast, String line, int after) Process Nested generics.private void
processSingleGeneric
(DetailAST ast, String line, int after) Process Single-generic.private void
processStart
(DetailAST ast) Checks the token for the start of Generics.void
visitToken
(DetailAST ast) Called to process a token.Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
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
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Field Details
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MSG_WS_PRECEDED
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_WS_FOLLOWED
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_WS_NOT_PRECEDED
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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MSG_WS_ILLEGAL_FOLLOW
A key is pointing to the warning message text in "messages.properties" file.- See Also:
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OPEN_ANGLE_BRACKET
Open angle bracket literal.- See Also:
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CLOSE_ANGLE_BRACKET
Close angle bracket literal.- See Also:
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depth
private int depthUsed to count the depth of a Generic expression.
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Constructor Details
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GenericWhitespaceCheck
public GenericWhitespaceCheck()
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Method Details
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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:
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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:
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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:
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beginTree
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
Description copied from class:AbstractCheck
Called to process a token.- Overrides:
visitToken
in classAbstractCheck
- Parameters:
ast
- the token to process
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processEnd
Checks the token for the end of Generics.- Parameters:
ast
- the token to check
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processNestedGenerics
Process Nested generics.- Parameters:
ast
- tokenline
- line contentafter
- position after
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processSingleGeneric
Process Single-generic.- Parameters:
ast
- tokenline
- line contentafter
- position after
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isGenericBeforeCtor
Checks if generic is before constructor invocation.- Parameters:
ast
- ast- Returns:
- true if generic before a constructor invocation
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isGenericBeforeMethod
Is generic before method reference.- Parameters:
ast
- ast- Returns:
- true if generic before a method ref
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isAfterMethodReference
Checks if current generic end ('>') is located aftermethod reference operator
.- Parameters:
genericEnd
-TokenTypes.GENERIC_END
- Returns:
- true if '>' follows after method reference.
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processStart
Checks the token for the start of Generics.- Parameters:
ast
- the token to check
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containsWhitespaceBetween
Returns whether the specified string contains only whitespace between specified indices.- Parameters:
fromIndex
- the index to start the search from. InclusivetoIndex
- the index to finish the search. Exclusiveline
- the line to check- Returns:
- whether there are only whitespaces (or nothing)
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containsWhitespaceBefore
Returns whether the specified string contains only whitespace up to specified index.- Parameters:
before
- the index to start the search from. Inclusiveline
- the index to finish the search. Exclusive- Returns:
true
if there are only whitespaces, false if there is nothing before or some other characters
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isCharacterValidAfterGenericEnd
private static boolean isCharacterValidAfterGenericEnd(char charAfter) Checks whether given character is valid to be right after generic ends.- Parameters:
charAfter
- character to check- Returns:
- checks if given character is valid
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