Class InnerAssignmentCheck
- 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.InnerAssignmentCheck
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- All Implemented Interfaces:
Configurable
,Contextualizable
public class InnerAssignmentCheck extends AbstractCheck
Checks for assignments in subexpressions, such as in
String s = Integer.toString(i = 2);
.Rationale: With the exception of
for
iterators, all assignments should occur in their own top-level statement to increase readability. With inner assignments like the above it is difficult to see all places where a variable is set.
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Field Summary
Fields Modifier and Type Field Description private static int[][]
ALLOWED_ASSIGNMENT_CONTEXT
List of allowed AST types from an assignment AST node towards the root.private static int[][]
ALLOWED_ASSIGNMENT_IN_COMPARISON_CONTEXT
List of allowed AST types from a comparison node (above an assignment) towards the root.private static int[]
COMPARISON_TYPES
The token types that identify comparison operators.private static int[][]
CONTROL_CONTEXT
List of allowed AST types from an assignment AST node towards the root.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 InnerAssignmentCheck()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description 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
isComparison(DetailAST ast)
Checks if an AST is a comparison operator.private static boolean
isInContext(DetailAST ast, int[]... contextSet)
Tests whether the provided AST is in one of the given contexts.private static boolean
isInNoBraceControlStatement(DetailAST ast)
Determines if ast is in the body of a flow control statement without braces.private static boolean
isInWhileIdiom(DetailAST ast)
Tests whether the given AST is used in the "assignment in while" idiom.void
visitToken(DetailAST ast)
Called to process a token.-
Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, destroy, finishTree, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, 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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ALLOWED_ASSIGNMENT_CONTEXT
private static final int[][] ALLOWED_ASSIGNMENT_CONTEXT
List of allowed AST types from an assignment AST node towards the root.
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CONTROL_CONTEXT
private static final int[][] CONTROL_CONTEXT
List of allowed AST types from an assignment AST node towards the root.
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ALLOWED_ASSIGNMENT_IN_COMPARISON_CONTEXT
private static final int[][] ALLOWED_ASSIGNMENT_IN_COMPARISON_CONTEXT
List of allowed AST types from a comparison node (above an assignment) towards the root.
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COMPARISON_TYPES
private static final int[] COMPARISON_TYPES
The token types that identify comparison operators.
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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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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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isInNoBraceControlStatement
private static boolean isInNoBraceControlStatement(DetailAST ast)
Determines if ast is in the body of a flow control statement without braces. An example of such a statement would beif (y < 0) x = y;
This leads to the following AST structure:
LITERAL_IF LPAREN EXPR // test RPAREN EXPR // body SEMI
We need to ensure that ast is in the body and not in the test.
- Parameters:
ast
- an assignment operator AST- Returns:
- whether ast is in the body of a flow control statement
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isInWhileIdiom
private static boolean isInWhileIdiom(DetailAST ast)
Tests whether the given AST is used in the "assignment in while" idiom.String line; while ((line = bufferedReader.readLine()) != null) { // process the line }
Assignment inside a condition is not a problem here, as the assignment is surrounded by an extra pair of parentheses. The comparison is!= null
and there is no chance that intention was to writeline == reader.readLine()
.- Parameters:
ast
- assignment AST- Returns:
- whether the context of the assignment AST indicates the idiom
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isComparison
private static boolean isComparison(DetailAST ast)
Checks if an AST is a comparison operator.- Parameters:
ast
- the AST to check- Returns:
- true iff ast is a comparison operator.
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isInContext
private static boolean isInContext(DetailAST ast, int[]... contextSet)
Tests whether the provided AST is in one of the given contexts.- Parameters:
ast
- the AST from which to start walking towards rootcontextSet
- the contexts to test against.- Returns:
- whether the parents nodes of ast match one of the allowed type paths.
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