////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2017 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.api.AbstractCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CheckUtils;
/**
* <p>
* Checks that each variable declaration is in its own statement
* and on its own line.
* </p>
* <p>
* Rationale: <a
* href="http://www.oracle.com/technetwork/java/javase/documentation/codeconventions-141270.html">
* the SUN Code conventions chapter 6.1</a> recommends that
* declarations should be one per line.
* </p>
* <p>
* An example of how to configure the check is:
* </p>
* <pre>
* <module name="MultipleVariableDeclarations"/>
* </pre>
* @author o_sukhodolsky
*/
public class MultipleVariableDeclarationsCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_MULTIPLE = "multiple.variable.declarations";
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_MULTIPLE_COMMA = "multiple.variable.declarations.comma";
@Override
public int[] getAcceptableTokens() {
return new int[] {TokenTypes.VARIABLE_DEF};
}
@Override
public int[] getDefaultTokens() {
return getAcceptableTokens();
}
@Override
public int[] getRequiredTokens() {
return getAcceptableTokens();
}
@Override
public void visitToken(DetailAST ast) {
DetailAST nextNode = ast.getNextSibling();
if (nextNode != null) {
final boolean isCommaSeparated = nextNode.getType() == TokenTypes.COMMA;
if (isCommaSeparated
|| nextNode.getType() == TokenTypes.SEMI) {
nextNode = nextNode.getNextSibling();
}
if (nextNode != null
&& nextNode.getType() == TokenTypes.VARIABLE_DEF) {
final DetailAST firstNode = CheckUtils.getFirstNode(ast);
if (isCommaSeparated) {
// Check if the multiple variable declarations are in a
// for loop initializer. If they are, then no warning
// should be displayed. Declaring multiple variables in
// a for loop initializer is a good way to minimize
// variable scope. Refer Feature Request Id - 2895985
// for more details
if (ast.getParent().getType() != TokenTypes.FOR_INIT) {
log(firstNode, MSG_MULTIPLE_COMMA);
}
}
else {
final DetailAST lastNode = getLastNode(ast);
final DetailAST firstNextNode = CheckUtils.getFirstNode(nextNode);
if (firstNextNode.getLineNo() == lastNode.getLineNo()) {
log(firstNode, MSG_MULTIPLE);
}
}
}
}
}
/**
* Finds sub-node for given node maximum (line, column) pair.
* @param node the root of tree for search.
* @return sub-node with maximum (line, column) pair.
*/
private static DetailAST getLastNode(final DetailAST node) {
DetailAST currentNode = node;
DetailAST child = node.getFirstChild();
while (child != null) {
final DetailAST newNode = getLastNode(child);
if (newNode.getLineNo() > currentNode.getLineNo()
|| newNode.getLineNo() == currentNode.getLineNo()
&& newNode.getColumnNo() > currentNode.getColumnNo()) {
currentNode = newNode;
}
child = child.getNextSibling();
}
return currentNode;
}
}