DefaultComesLastCheck.java
///////////////////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
// Copyright (C) 2001-2024 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;
/**
* <p>
* Check that the {@code default} is after all the cases in a {@code switch} statement.
* </p>
* <p>
* Rationale: Java allows {@code default} anywhere within the
* {@code switch} statement. But it is more readable if it comes after the last {@code case}.
* </p>
* <ul>
* <li>
* Property {@code skipIfLastAndSharedWithCase} - Control whether to allow {@code default}
* along with {@code case} if they are not last.
* Type is {@code boolean}.
* Default value is {@code false}.
* </li>
* </ul>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code default.comes.last}
* </li>
* <li>
* {@code default.comes.last.in.casegroup}
* </li>
* </ul>
*
* @since 3.4
*/
@StatelessCheck
public class DefaultComesLastCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "default.comes.last";
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE =
"default.comes.last.in.casegroup";
/** Control whether to allow {@code default} along with {@code case} if they are not last. */
private boolean skipIfLastAndSharedWithCase;
@Override
public int[] getAcceptableTokens() {
return getRequiredTokens();
}
@Override
public int[] getDefaultTokens() {
return getRequiredTokens();
}
@Override
public int[] getRequiredTokens() {
return new int[] {
TokenTypes.LITERAL_DEFAULT,
};
}
/**
* Setter to control whether to allow {@code default} along with
* {@code case} if they are not last.
*
* @param newValue whether to ignore checking.
* @since 7.7
*/
public void setSkipIfLastAndSharedWithCase(boolean newValue) {
skipIfLastAndSharedWithCase = newValue;
}
@Override
public void visitToken(DetailAST ast) {
final DetailAST defaultGroupAST = ast.getParent();
// Switch rules are not subject to fall through.
final boolean isSwitchRule = defaultGroupAST.getType() == TokenTypes.SWITCH_RULE;
if (skipIfLastAndSharedWithCase && !isSwitchRule) {
if (isNextSiblingOf(ast, TokenTypes.LITERAL_CASE)) {
log(ast, MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE);
}
else if (ast.getPreviousSibling() == null
&& isNextSiblingOf(defaultGroupAST,
TokenTypes.CASE_GROUP)) {
log(ast, MSG_KEY);
}
}
else if (isNextSiblingOf(defaultGroupAST,
TokenTypes.CASE_GROUP)
|| isNextSiblingOf(defaultGroupAST,
TokenTypes.SWITCH_RULE)) {
log(ast, MSG_KEY);
}
}
/**
* Return true only if passed tokenType in argument is found or returns false.
*
* @param ast root node.
* @param tokenType tokentype to be processed.
* @return true if desired token is found or else false.
*/
private static boolean isNextSiblingOf(DetailAST ast, int tokenType) {
return ast.getNextSibling() != null && ast.getNextSibling().getType() == tokenType;
}
}