Class InnerAssignmentCheck
- All Implemented Interfaces:
Configurable
,Contextualizable
Checks for assignments in subexpressions, such as in
String s = Integer.toString(i = 2);
.
Rationale: With the exception of for
iterators and assignment in while
idiom,
all assignments should occur in their own top-level statement to increase readability.
With inner assignments like the one given above, it is difficult to see all places
where a variable is set.
Note: Check allows usage of the popular 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 write line == reader.readLine()
.
To configure the check:
<module name="InnerAssignment"/>
Example:
class MyClass { void foo() { int a, b; a = b = 5; // violation, assignment to each variable should be in a separate statement a = b += 5; // violation a = 5; // OK b = 5; // OK a = 5; b = 5; // OK double myDouble; double[] doubleArray = new double[] {myDouble = 4.5, 15.5}; // violation String nameOne; List<String> myList = new ArrayList<String>(); myList.add(nameOne = "tom"); // violation for (int k = 0; k < 10; k = k + 2) { // OK // some code } boolean someVal; if (someVal = true) { // violation // some code } while (someVal = false) {} // violation InputStream is = new FileInputStream("textFile.txt"); while ((b = is.read()) != -1) { // OK, this is a common idiom // some code } } boolean testMethod() { boolean val; return val = true; // violation } }
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
-
assignment.inner.avoid
- Since:
- 3.0
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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
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint[]
The configurable token set.int[]
Returns the default token a check is interested in.int[]
The tokens that this check must be registered for.void
visitToken
(DetailAST ast) Called to process a token.Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck
beginTree, clearMessages, destroy, finishTree, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, 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_KEY
A key is pointing to the warning message text in "messages.properties" file.- See Also:
-
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Constructor Details
-
InnerAssignmentCheck
public InnerAssignmentCheck()
-
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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:
-
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:
-
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:
-
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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