public final class OneStatementPerLineCheck extends AbstractCheck
Checks that there is only one statement per line.
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, import statements, assignment statements, expression statements, increment statements, object creation statements, 'for loop' statements, 'break' statements, 'continue' statements, 'return' statements, resources statements (optional).
treatTryResourcesAsStatement - Enable resources processing.
Type is boolean.
Default value is false.
An example of how to configure this Check:
<module name="OneStatementPerLine"/>
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
An example of how to configure the check to treat resources in a try statement as statements to require them on their own line:
<module name="OneStatementPerLine"> <property name="treatTryResourcesAsStatement" value="true"/> </module>
Note: resource declarations can contain variable definitions and variable references (from java9). When property "treatTryResourcesAsStatement" is enabled, this check is only applied to variable definitions. If there are one or more variable references and one variable definition on the same line in resources declaration, there is no violation. The following examples will illustrate difference:
OutputStream s1 = new PipedOutputStream();
OutputStream s2 = new PipedOutputStream();
// only one statement(variable definition) with two variable references
try (s1; s2; OutputStream s3 = new PipedOutputStream();) // OK
{}
// two statements with variable definitions
try (Reader r = new PipedReader(); s2; Reader s3 = new PipedReader() // violation
) {}
Parent is com.puppycrawl.tools.checkstyle.TreeWalker
Violation Message Keys:
multiple.statements.line
AutomaticBean.OutputStreamOptions| Modifier and Type | Field and Description |
|---|---|
static String |
MSG_KEY
A key is pointing to the warning message text in "messages.properties"
file.
|
| Constructor and Description |
|---|
OneStatementPerLineCheck() |
| Modifier and Type | Method and Description |
|---|---|
void |
beginTree(DetailAST rootAST)
Called before the starting to process a tree.
|
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 |
leaveToken(DetailAST ast)
Called after all the child nodes have been process.
|
void |
setTreatTryResourcesAsStatement(boolean treatTryResourcesAsStatement)
Setter to enable resources processing.
|
void |
visitToken(DetailAST ast)
Called to process a token.
|
clearMessages, destroy, finishTree, getFileContents, getLine, getLines, getMessages, getTabWidth, getTokenNames, init, isCommentNodesRequired, log, log, log, setFileContents, setTabWidth, setTokensfinishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverityconfigure, contextualize, getConfiguration, setupChildpublic static final String MSG_KEY
public OneStatementPerLineCheck()
public void setTreatTryResourcesAsStatement(boolean treatTryResourcesAsStatement)
treatTryResourcesAsStatement - user's value of treatTryResourcesAsStatement.public int[] getDefaultTokens()
AbstractCheckgetDefaultTokens in class AbstractCheckTokenTypespublic int[] getAcceptableTokens()
AbstractCheckgetAcceptableTokens in class AbstractCheckTokenTypespublic int[] getRequiredTokens()
AbstractCheckgetRequiredTokens in class AbstractCheckTokenTypespublic void beginTree(DetailAST rootAST)
AbstractCheckbeginTree in class AbstractCheckrootAST - the root of the treepublic void visitToken(DetailAST ast)
AbstractCheckvisitToken in class AbstractCheckast - the token to processpublic void leaveToken(DetailAST ast)
AbstractCheckleaveToken in class AbstractCheckast - the token leavingCopyright © 2001–2020. All rights reserved.