////////////////////////////////////////////////////////////////////////////////
// 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.utils.CommonUtils;
/**
* <p>
* Checks that non-whitespace characters are separated by no more than one
* whitespace. Separating characters by tabs or multiple spaces will be
* reported. Currently the check doesn't permit horizontal alignment. To inspect
* whitespaces before and after comments, set the property
* <b>validateComments</b> to true.
* </p>
*
* <p>
* Setting <b>validateComments</b> to false will ignore cases like:
* </p>
*
* <pre>
* int i; // Multiple whitespaces before comment tokens will be ignored.
* private void foo(int /* whitespaces before and after block-comments will be
* ignored */ i) {
* </pre>
*
* <p>
* Sometimes, users like to space similar items on different lines to the same
* column position for easier reading. This feature isn't supported by this
* check, so both braces in the following case will be reported as violations.
* </p>
*
* <pre>
* public long toNanos(long d) { return d; } // 2 violations
* public long toMicros(long d) { return d / (C1 / C0); }
* </pre>
*
* <p>
* Check have following options:
* </p>
*
* <ul>
* <li>validateComments - Boolean when set to {@code true}, whitespaces
* surrounding comments will be ignored. Default value is {@code false}.</li>
* </ul>
*
* <p>
* To configure the check:
* </p>
*
* <pre>
* <module name="SingleSpaceSeparator"/>
* </pre>
*
* <p>
* To configure the check so that it validates comments:
* </p>
*
* <pre>
* <module name="SingleSpaceSeparator">
* <property name="validateComments" value="true"/>
* </module>
* </pre>
*
* @author Robert Whitebit
* @author Richard Veach
*/
public class SingleSpaceSeparatorCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties"
* file.
*/
public static final String MSG_KEY = "single.space.separator";
/** Indicates if whitespaces surrounding comments will be ignored. */
private boolean validateComments;
/**
* Sets whether or not to validate surrounding whitespaces at comments.
*
* @param validateComments {@code true} to validate surrounding whitespaces at comments.
*/
public void setValidateComments(boolean validateComments) {
this.validateComments = validateComments;
}
@Override
public int[] getDefaultTokens() {
return CommonUtils.EMPTY_INT_ARRAY;
}
// -@cs[SimpleAccessorNameNotation] Overrides method from base class.
// Issue: https://github.com/sevntu-checkstyle/sevntu.checkstyle/issues/166
@Override
public boolean isCommentNodesRequired() {
return validateComments;
}
@Override
public void beginTree(DetailAST rootAST) {
visitEachToken(rootAST);
}
/**
* Examines every sibling and child of {@code node} for violations.
*
* @param node The node to start examining.
*/
private void visitEachToken(DetailAST node) {
DetailAST sibling = node;
while (sibling != null) {
final int columnNo = sibling.getColumnNo() - 1;
if (columnNo >= 0
&& !isTextSeparatedCorrectlyFromPrevious(getLine(sibling.getLineNo() - 1),
columnNo)) {
log(sibling.getLineNo(), columnNo, MSG_KEY);
}
if (sibling.getChildCount() > 0) {
visitEachToken(sibling.getFirstChild());
}
sibling = sibling.getNextSibling();
}
}
/**
* Checks if characters in {@code line} at and around {@code columnNo} has
* the correct number of spaces. to return {@code true} the following
* conditions must be met:<br />
* - the character at {@code columnNo} is the first in the line.<br />
* - the character at {@code columnNo} is not separated by whitespaces from
* the previous non-whitespace character. <br />
* - the character at {@code columnNo} is separated by only one whitespace
* from the previous non-whitespace character.<br />
* - {@link #validateComments} is disabled and the previous text is the
* end of a block comment.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if the text at {@code columnNo} is separated
* correctly from the previous token.
*/
private boolean isTextSeparatedCorrectlyFromPrevious(String line, int columnNo) {
return isSingleSpace(line, columnNo)
|| !isWhitespace(line, columnNo)
|| isFirstInLine(line, columnNo)
|| !validateComments && isBlockCommentEnd(line, columnNo);
}
/**
* Checks if the {@code line} at {@code columnNo} is a single space, and not
* preceded by another space.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if the character at {@code columnNo} is a space, and
* not preceded by another space.
*/
private static boolean isSingleSpace(String line, int columnNo) {
return !isPrecededByMultipleWhitespaces(line, columnNo)
&& isSpace(line, columnNo);
}
/**
* Checks if the {@code line} at {@code columnNo} is a space.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if the character at {@code columnNo} is a space.
*/
private static boolean isSpace(String line, int columnNo) {
return line.charAt(columnNo) == ' ';
}
/**
* Checks if the {@code line} at {@code columnNo} is preceded by at least 2
* whitespaces.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if there are at least 2 whitespace characters before
* {@code columnNo}.
*/
private static boolean isPrecededByMultipleWhitespaces(String line, int columnNo) {
return columnNo >= 1
&& Character.isWhitespace(line.charAt(columnNo))
&& Character.isWhitespace(line.charAt(columnNo - 1));
}
/**
* Checks if the {@code line} at {@code columnNo} is a whitespace character.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if the character at {@code columnNo} is a
* whitespace.
*/
private static boolean isWhitespace(String line, int columnNo) {
return Character.isWhitespace(line.charAt(columnNo));
}
/**
* Checks if the {@code line} up to and including {@code columnNo} is all
* non-whitespace text encountered.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if the column position is the first non-whitespace
* text on the {@code line}.
*/
private static boolean isFirstInLine(String line, int columnNo) {
return CommonUtils.isBlank(line.substring(0, columnNo + 1));
}
/**
* Checks if the {@code line} at {@code columnNo} is the end of a comment,
* '*/'.
*
* @param line The line in the file to examine.
* @param columnNo The column position in the {@code line} to examine.
* @return {@code true} if the previous text is a end comment block.
*/
private static boolean isBlockCommentEnd(String line, int columnNo) {
return line.substring(0, columnNo).trim().endsWith("*/");
}
}