UnnecessarySemicolonAfterTypeMemberDeclarationCheck.java
///////////////////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
// Copyright (C) 2001-2022 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
///////////////////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.checks.coding;
import com.puppycrawl.tools.checkstyle.StatelessCheck;
import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
/**
* <p>
* Checks if unnecessary semicolon is used after type member declaration.
* </p>
* <p>
* This check is not applicable to empty statements (unnecessary semicolons inside methods or
* init blocks),
* <a href="https://checkstyle.org/config_coding.html#EmptyStatement">EmptyStatement</a>
* is responsible for it.
* </p>
* <ul>
* <li>
* Property {@code tokens} - tokens to check
* Type is {@code java.lang.String[]}.
* Validation type is {@code tokenSet}.
* Default value is:
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
* CLASS_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
* INTERFACE_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
* ENUM_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_DEF">
* ANNOTATION_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
* VARIABLE_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
* ANNOTATION_FIELD_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STATIC_INIT">
* STATIC_INIT</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INSTANCE_INIT">
* INSTANCE_INIT</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CTOR_DEF">
* CTOR_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
* METHOD_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_CONSTANT_DEF">
* ENUM_CONSTANT_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#COMPACT_CTOR_DEF">
* COMPACT_CTOR_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
* RECORD_DEF</a>.
* </li>
* </ul>
* <p>
* To configure the check:
* </p>
* <pre>
* <module name="UnnecessarySemicolonAfterTypeMemberDeclaration"/>
* </pre>
* <p>
* Results in following:
* </p>
* <pre>
* class A {
* ; // violation, standalone semicolon
* {}; // violation, extra semicolon after init block
* static {}; // violation, extra semicolon after static init block
* A(){}; // violation, extra semicolon after constructor definition
* void method() {}; // violation, extra semicolon after method definition
* int field = 10;; // violation, extra semicolon after field declaration
*
* {
* ; // no violation, it is empty statement inside init block
* }
*
* static {
* ; // no violation, it is empty statement inside static init block
* }
*
* void anotherMethod() {
* ; // no violation, it is empty statement
* if(true); // no violation, it is empty statement
* }
* }
* </pre>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code unnecessary.semicolon}
* </li>
* </ul>
*
* @since 8.24
*/
@StatelessCheck
public final class UnnecessarySemicolonAfterTypeMemberDeclarationCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_SEMI = "unnecessary.semicolon";
@Override
public int[] getDefaultTokens() {
return getAcceptableTokens();
}
@Override
public int[] getAcceptableTokens() {
return new int[] {
TokenTypes.CLASS_DEF,
TokenTypes.INTERFACE_DEF,
TokenTypes.ENUM_DEF,
TokenTypes.ANNOTATION_DEF,
TokenTypes.VARIABLE_DEF,
TokenTypes.ANNOTATION_FIELD_DEF,
TokenTypes.STATIC_INIT,
TokenTypes.INSTANCE_INIT,
TokenTypes.CTOR_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.ENUM_CONSTANT_DEF,
TokenTypes.COMPACT_CTOR_DEF,
TokenTypes.RECORD_DEF,
};
}
@Override
public int[] getRequiredTokens() {
return CommonUtil.EMPTY_INT_ARRAY;
}
@Override
public void visitToken(DetailAST ast) {
switch (ast.getType()) {
case TokenTypes.CLASS_DEF:
case TokenTypes.INTERFACE_DEF:
case TokenTypes.ENUM_DEF:
case TokenTypes.ANNOTATION_DEF:
case TokenTypes.RECORD_DEF:
checkTypeDefinition(ast);
break;
case TokenTypes.VARIABLE_DEF:
checkVariableDefinition(ast);
break;
case TokenTypes.ENUM_CONSTANT_DEF:
checkEnumConstant(ast);
break;
default:
checkTypeMember(ast);
break;
}
}
/**
* Checks if type member has unnecessary semicolon.
*
* @param ast type member
*/
private void checkTypeMember(DetailAST ast) {
if (isSemicolon(ast.getNextSibling())) {
log(ast.getNextSibling(), MSG_SEMI);
}
}
/**
* Checks if type definition has unnecessary semicolon.
*
* @param ast type definition
*/
private void checkTypeDefinition(DetailAST ast) {
if (!ScopeUtil.isOuterMostType(ast) && isSemicolon(ast.getNextSibling())) {
log(ast.getNextSibling(), MSG_SEMI);
}
final DetailAST firstMember =
ast.findFirstToken(TokenTypes.OBJBLOCK).getFirstChild().getNextSibling();
if (isSemicolon(firstMember) && !ScopeUtil.isInEnumBlock(firstMember)) {
log(firstMember, MSG_SEMI);
}
}
/**
* Checks if variable definition has unnecessary semicolon.
*
* @param variableDef variable definition
*/
private void checkVariableDefinition(DetailAST variableDef) {
if (isSemicolon(variableDef.getLastChild()) && isSemicolon(variableDef.getNextSibling())) {
log(variableDef.getNextSibling(), MSG_SEMI);
}
}
/**
* Checks if enum constant has unnecessary semicolon.
*
* @param ast enum constant
*/
private void checkEnumConstant(DetailAST ast) {
final DetailAST next = ast.getNextSibling();
if (isSemicolon(next) && isSemicolon(next.getNextSibling())) {
log(next.getNextSibling(), MSG_SEMI);
}
}
/**
* Checks that {@code ast} is a semicolon.
*
* @param ast token to check
* @return true if ast is semicolon, false otherwise
*/
private static boolean isSemicolon(DetailAST ast) {
return ast.getType() == TokenTypes.SEMI;
}
}