Package net.sourceforge.pmd.lang.java.rule.codestyle

Class ConfusingTernaryRule

java.lang.Object
net.sourceforge.pmd.properties.AbstractPropertySource
net.sourceforge.pmd.lang.rule.AbstractRule
net.sourceforge.pmd.lang.java.rule.AbstractJavaRule
net.sourceforge.pmd.lang.java.rule.AbstractJavaRulechainRule
net.sourceforge.pmd.lang.java.rule.codestyle.ConfusingTernaryRule
All Implemented Interfaces:
AstVisitor, JavaVisitor, Rule, PropertySource
public class ConfusingTernaryRule extends AbstractJavaRulechainRule
if (x != y) { diff(); } else { same(); } and
(!x ? diff() : same());

XPath can handle the easy cases, e.g.:

    //IfStatement[
      Statement[2]
      and Expression[
        EqualityExpression[@Image="!="] or
        UnaryExpressionNotPlusMinus[@Image="!"]]]

But "&&" and "||" are difficult, since we need a match for all children instead of just one. This can be done by using a double-negative, e.g.:

    not(*[not(matchme)])

Still, XPath is unable to handle arbitrarily nested cases, since it lacks recursion, e.g.:

 if (((x != !y)) || !(x)) {
     diff();
 } else {
     same();
 }