private static final ImmutableSet<String> OPTIONAL_CLASSES =
ImmutableSet.of(com.google.common.base.Optional.class.getName(), "java.util.Optional");
private static final Set<Kind> COMPARISON_OPERATORS =
EnumSet.of(Kind.EQUAL_TO, Kind.NOT_EQUAL_TO);
private static boolean isNull(ExpressionTree tree) {
return tree.getKind() == Kind.NULL_LITERAL;
}
private static boolean isOptional(ExpressionTree tree, VisitorState state) {
Type type = ASTHelpers.getType(tree);
for (String className : OPTIONAL_CLASSES) {
if (ASTHelpers.isSameType(type, state.getTypeFromString(className), state)) {
return true;
}
}
return false;
}
private boolean isSuppressed(Tree tree, String suppression) {
SuppressWarnings annotation = ASTHelpers.getAnnotation(ASTHelpers.getSymbol(tree), SuppressWarnings.class);
return annotation != null && Arrays.stream(annotation.value()).anyMatch(suppression::equals);
}
@Override
public Description matchBinary(BinaryTree tree, VisitorState state) {
if (!COMPARISON_OPERATORS.contains(tree.getKind())) {
return Description.NO_MATCH;
}
ExpressionTree leftOperand = tree.getLeftOperand();
ExpressionTree rightOperand = tree.getRightOperand();
if (isNull(leftOperand) && isOptional(rightOperand, state) ||
isNull(rightOperand) && isOptional(leftOperand, state)) {
return describeMatch(tree);
}
return Description.NO_MATCH;
}
我想我在 ErrorProne 中得到了这个工作。如果我得到一些测试,我会把它回馈给社区。