public class FallThroughCheck extends AbstractCheck
Checks for fall-through in switch statements.
Finds locations where a case contains Java code but lacks a
break, return, throw or continue statement.
The check honors special comments to suppress the warning.
By default the texts
"fallthru", "fall thru", "fall-thru",
"fallthrough", "fall through", "fall-through"
"fallsthrough", "falls through", "falls-through" (case sensitive).
The comment containing these words must be all on one line,
and must be on the last non-empty line before the case triggering
the warning or on the same line before the case(ugly, but possible).
switch (i) {
case 0:
i++; // fall through
case 1:
i++;
// falls through
case 2:
case 3:
case 4: {
i++;
}
// fallthrough
case 5:
i++;
/* fallthru */case 6:
i++;
// fall-through
case 7:
i++;
break;
}
Note: The check assumes that there is no unreachable code in the case.
The following fragment of code will NOT trigger the check, because of the comment "fallthru" or any Java code in case 5 are absent.
case 3:
x = 2;
// fallthru
case 4:
case 5: // violation
case 6:
break;
checkLastCaseGroup - Control whether the last case group must be checked.
Type is boolean.
Default value is false.
reliefPattern - Define the RegExp to match the relief comment that suppresses
the warning about a fall through.
Type is java.util.regex.Pattern.
Default value is "falls?[ -]?thr(u|ough)".
To configure the check:
<module name="FallThrough"/>
or
<module name="FallThrough"> <property name="reliefPattern" value="continue in next case"/> </module>
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
fall.through
fall.through.last
AutomaticBean.OutputStreamOptions| Modifier and Type | Field and Description |
|---|---|
static java.lang.String |
MSG_FALL_THROUGH
A key is pointing to the warning message text in "messages.properties"
file.
|
static java.lang.String |
MSG_FALL_THROUGH_LAST
A key is pointing to the warning message text in "messages.properties"
file.
|
| Constructor and Description |
|---|
FallThroughCheck() |
| Modifier and Type | Method and 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.
|
void |
setCheckLastCaseGroup(boolean value)
Setter to control whether the last case group must be checked.
|
void |
setReliefPattern(java.util.regex.Pattern pattern)
Setter to define the RegExp to match the relief comment that suppresses
the warning about a fall through.
|
void |
visitToken(DetailAST ast)
Called to process a token.
|
beginTree, clearMessages, destroy, finishTree, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, log, log, log, setFileContents, setTabWidth, setTokensfinishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverityconfigure, contextualize, getConfiguration, setupChildpublic static final java.lang.String MSG_FALL_THROUGH
public static final java.lang.String MSG_FALL_THROUGH_LAST
public FallThroughCheck()
public int[] getDefaultTokens()
AbstractCheckgetDefaultTokens in class AbstractCheckTokenTypespublic int[] getRequiredTokens()
AbstractCheckgetRequiredTokens in class AbstractCheckTokenTypespublic int[] getAcceptableTokens()
AbstractCheckgetAcceptableTokens in class AbstractCheckTokenTypespublic void setReliefPattern(java.util.regex.Pattern pattern)
pattern - The regular expression pattern.public void setCheckLastCaseGroup(boolean value)
value - new value of the property.public void visitToken(DetailAST ast)
AbstractCheckvisitToken in class AbstractCheckast - the token to processCopyright © 2001-2020. All Rights Reserved.