Since: PMD 3.2
To make sure the full stacktrace is printed out, use the logging statement with two arguments: a String and a Throwable.
//CatchStatement/Block/BlockStatement/Statement/StatementExpression
/PrimaryExpression[PrimaryPrefix/Name[starts-with(@Image,
concat(ancestor::ClassOrInterfaceDeclaration/ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/FieldDeclaration
[Type//ClassOrInterfaceType[@Image='Log']]
/VariableDeclarator/VariableDeclaratorId/@Image, '.'))]]
[PrimarySuffix/Arguments[@ArgumentCount='1']]
[PrimarySuffix/Arguments//Name/@Image = ancestor::CatchStatement/FormalParameter/VariableDeclaratorId/@Image]
public class Main {
private static final Log _LOG = LogFactory.getLog( Main.class );
void bar() {
try {
} catch( Exception e ) {
_LOG.error( e ); //Wrong!
} catch( OtherException oe ) {
_LOG.error( oe.getMessage(), oe ); //Correct
}
}
}
Since: PMD 3.3
A logger should normally be defined private static final and be associated with the correct class. Private final Log log; is also allowed for rare cases where loggers need to be passed around, with the restriction that the logger needs to be passed into the constructor.
//ClassOrInterfaceBodyDeclaration[FieldDeclaration//ClassOrInterfaceType[@Image='Log']
and
not(FieldDeclaration[@Final='true'][@Static='true'][@Private='true'][.//VariableDeclaratorId[@Image=$staticLoggerName]]
//ArgumentList//ClassOrInterfaceType/@Image = ancestor::ClassOrInterfaceDeclaration/@Image)
and
not(FieldDeclaration[@Final='true'][@Private='true'][.//VariableDeclaratorId[@Image='log']]
[count(.//VariableInitializer)=0]
[ancestor::ClassOrInterfaceBody//StatementExpression[.//PrimaryExpression/descendant::*[@Image='log']][count(.//AllocationExpression)=0]]
)]
public class Foo {
private static final Log LOG = LogFactory.getLog(Foo.class); // proper way
protected Log LOG = LogFactory.getLog(Testclass.class); // wrong approach
}
This rule has the following properties:
| Name | Default Value | Description |
|---|---|---|
| staticLoggerName | LOG | Name of the static Logger variable |
Since: PMD 4.3
When log messages are composed by concatenating strings, the whole section should be guarded by a isDebugEnabled() check to avoid performance and memory issues.
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.logging.GuardDebugLoggingRule
Example(s):
public class Test {
private static final Log __log = LogFactory.getLog(Test.class);
public void test() {
// okay:
__log.debug("log something");
// okay:
__log.debug("log something with exception", e);
// bad:
__log.debug("log something" + " and " + "concat strings");
// bad:
__log.debug("log something" + " and " + "concat strings", e);
// good:
if (__log.isDebugEnabled()) {
__log.debug("bla" + "",e );
}
}
}
This rule has the following properties:
| Name | Default Value | Description |
|---|---|---|
| violationSuppressRegex | Suppress violations with messages matching a regular expression | |
| violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. | |
| guardsMethods | [] | method use to guard the log statement |
| logLevels | [] | LogLevels to guard |
Since: PMD 5.1.0
Whenever using a log level, one should check if the loglevel is actually enabled, or otherwise skip the associate String creation and manipulation.
This rule is defined by the following Java class: net.sourceforge.pmd.lang.java.rule.logging.GuardLogStatementRule
Example(s):
// Add this for performance
if (log.isDebugEnabled() { ...
log.debug("This happens");
This rule has the following properties:
| Name | Default Value | Description |
|---|---|---|
| violationSuppressRegex | Suppress violations with messages matching a regular expression | |
| violationSuppressXPath | Suppress violations on nodes which match a given relative XPath expression. | |
| guardsMethods | [] | method use to guard the log statement |
| logLevels | [] | LogLevels to guard |