////////////////////////////////////////////////////////////////////////////////
// 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.whitespace;
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.CommonUtils;
/**
* <p>
* Checks that there is no whitespace before a token.
* More specifically, it checks that it is not preceded with whitespace,
* or (if line breaks are allowed) all characters on the line before are
* whitespace. To allow line breaks before a token, set property
* allowLineBreaks to true.
* </p>
* <p> By default the check will check the following operators:
* {@link TokenTypes#COMMA COMMA},
* {@link TokenTypes#SEMI SEMI},
* {@link TokenTypes#POST_DEC POST_DEC},
* {@link TokenTypes#POST_INC POST_INC},
* {@link TokenTypes#ELLIPSIS ELLIPSIS}.
* {@link TokenTypes#DOT DOT} is also an acceptable token in a configuration
* of this check.
* </p>
*
* <p>
* An example of how to configure the check is:
* </p>
* <pre>
* <module name="NoWhitespaceBefore"/>
* </pre>
* <p> An example of how to configure the check to allow line breaks before
* a {@link TokenTypes#DOT DOT} token is:
* </p>
* <pre>
* <module name="NoWhitespaceBefore">
* <property name="tokens" value="DOT"/>
* <property name="allowLineBreaks" value="true"/>
* </module>
* </pre>
* @author Rick Giles
* @author lkuehne
*/
public class NoWhitespaceBeforeCheck
extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "ws.preceded";
/** Whether whitespace is allowed if the AST is at a linebreak. */
private boolean allowLineBreaks;
@Override
public int[] getDefaultTokens() {
return new int[] {
TokenTypes.COMMA,
TokenTypes.SEMI,
TokenTypes.POST_INC,
TokenTypes.POST_DEC,
TokenTypes.ELLIPSIS,
};
}
@Override
public int[] getAcceptableTokens() {
return new int[] {
TokenTypes.COMMA,
TokenTypes.SEMI,
TokenTypes.POST_INC,
TokenTypes.POST_DEC,
TokenTypes.DOT,
TokenTypes.GENERIC_START,
TokenTypes.GENERIC_END,
TokenTypes.ELLIPSIS,
TokenTypes.METHOD_REF,
};
}
@Override
public int[] getRequiredTokens() {
return CommonUtils.EMPTY_INT_ARRAY;
}
@Override
public void visitToken(DetailAST ast) {
final String line = getLine(ast.getLineNo() - 1);
final int before = ast.getColumnNo() - 1;
if ((before < 0 || Character.isWhitespace(line.charAt(before)))
&& !isInEmptyForInitializer(ast)) {
boolean flag = !allowLineBreaks;
// verify all characters before '.' are whitespace
for (int i = 0; !flag && i < before; i++) {
if (!Character.isWhitespace(line.charAt(i))) {
flag = true;
break;
}
}
if (flag) {
log(ast.getLineNo(), before, MSG_KEY, ast.getText());
}
}
}
/**
* Checks that semicolon is in empty for initializer.
* @param semicolonAst DetailAST of semicolon.
* @return true if semicolon is in empty for initializer.
*/
private static boolean isInEmptyForInitializer(DetailAST semicolonAst) {
boolean result = false;
if (semicolonAst.getType() == TokenTypes.SEMI) {
final DetailAST sibling = semicolonAst.getPreviousSibling();
if (sibling != null
&& sibling.getType() == TokenTypes.FOR_INIT
&& sibling.getChildCount() == 0) {
result = true;
}
}
return result;
}
/**
* Control whether whitespace is flagged at line breaks.
* @param allowLineBreaks whether whitespace should be
* flagged at line breaks.
*/
public void setAllowLineBreaks(boolean allowLineBreaks) {
this.allowLineBreaks = allowLineBreaks;
}
}