com.qulice.checkstyle.NonStaticMethodCheck Maven / Gradle / Ivy
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package com.qulice.checkstyle;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.FileContents;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
import java.util.regex.Pattern;
/**
* Checks that non static method must contain at least one reference to
* {@code this}.
*
* If your method doesn't need {@code this} than why it is not
* {@code static}?
*
* The exception here is when method has {@code @Override} annotation. There's
* no concept of inheritance and polymorphism for static methods even if they
* don't need {@code this} to perform the actual work.
*
* Another exception is when method is {@code abstract} or {@code native}.
* Such methods don't have body so detection based on {@code this} doesn't
* make sense for them.
*
* @since 0.3
*/
public final class NonStaticMethodCheck extends AbstractCheck {
/**
* Files to exclude from this check.
* This is mostly to exclude JUnit tests.
*/
private Pattern exclude = Pattern.compile("^$");
/**
* Exclude files matching given pattern.
* @param excl Regexp of classes to exclude.
*/
public void setExcludeFileNamePattern(final String excl) {
this.exclude = Pattern.compile(excl);
}
@Override
public int[] getDefaultTokens() {
return new int[] {
TokenTypes.METHOD_DEF,
};
}
@Override
public int[] getAcceptableTokens() {
return this.getDefaultTokens();
}
@Override
public int[] getRequiredTokens() {
return this.getDefaultTokens();
}
@Override
public void visitToken(final DetailAST ast) {
if (this.exclude.matcher(this.getFileContents().getFileName())
.find()) {
return;
}
if (TokenTypes.CLASS_DEF == ast.getParent().getParent().getType()) {
this.checkClassMethod(ast);
}
}
/**
* Check that non static class method refer {@code this}. Methods that
* are {@code native}, {@code abstract} or annotated with {@code @Override}
* are excluded. Additionally, if the method only throws an exception, it
* too is excluded.
* @param method DetailAST of method
*/
private void checkClassMethod(final DetailAST method) {
final DetailAST modifiers = method
.findFirstToken(TokenTypes.MODIFIERS);
if (modifiers.findFirstToken(TokenTypes.LITERAL_STATIC) != null) {
return;
}
final boolean onlythrow =
method.branchContains(TokenTypes.LITERAL_THROW)
&& !method.branchContains(TokenTypes.LCURLY)
&& this.countSemiColons(method) == 1;
if (!AnnotationUtil.containsAnnotation(method, "Override")
&& !isInAbstractOrNativeMethod(method)
&& !method.branchContains(TokenTypes.LITERAL_THIS)
&& !onlythrow) {
final int line = method.getLineNo();
this.log(
line,
// @checkstyle LineLength (1 line)
"This method must be static, because it does not refer to \"this\""
);
}
}
/**
* Determines whether a method is {@code abstract} or {@code native}.
* @param method Method to check.
* @return True if method is abstract or native.
*/
private static boolean isInAbstractOrNativeMethod(final DetailAST method) {
final DetailAST modifiers = method.findFirstToken(TokenTypes.MODIFIERS);
return modifiers.branchContains(TokenTypes.ABSTRACT)
|| modifiers.branchContains(TokenTypes.LITERAL_NATIVE);
}
/**
* Determines the number semicolons in a method excluding those in
* comments.
* @param method Method to count
* @return The number of semicolons in the method as an int
*/
private int countSemiColons(final DetailAST method) {
final DetailAST openingbrace = method.findFirstToken(TokenTypes.SLIST);
int count = 0;
if (openingbrace != null) {
final DetailAST closingbrace =
openingbrace.findFirstToken(TokenTypes.RCURLY);
final int lastline = closingbrace.getLineNo();
final int firstline = openingbrace.getLineNo();
final FileContents contents = this.getFileContents();
for (int line = firstline - 1; line < lastline; line += 1) {
if (!contents.lineIsBlank(line)
&& !contents.lineIsComment(line)
&& contents.getLine(line).contains(";")) {
count += 1;
}
}
}
return count;
}
}