src/main/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorCheck.java - platform/external/checkstyle - Git at Google

 ////////////////////////////////////////////////////////////////////////////////
 // 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.StatelessCheck;
 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;  &#47;&#47; Multiple whitespaces before comment tokens will be ignored.
  * private void foo(int  &#47;* whitespaces before and after block-comments will be
  * ignored *&#47;  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;             }  &#47;&#47; 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>
  * &lt;module name=&quot;SingleSpaceSeparator&quot;/&gt;
  * </pre>
  *
  * <p>
  * To configure the check so that it validates comments:
  * </p>
  *
  * <pre>
  * &lt;module name=&quot;SingleSpaceSeparator&quot;&gt;
  * &lt;property name=&quot;validateComments&quot; value=&quot;true&quot;/&gt;
  * &lt;/module&gt;
  * </pre>
  *
  * @author Robert Whitebit
  * @author Richard Veach
  */
 @StatelessCheck
 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 getRequiredTokens();
     }

     @Override
     public int[] getAcceptableTokens() {
         return getRequiredTokens();
     }

     @Override
     public int[] getRequiredTokens() {
         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;

             // in such expression: "j  =123", placed at the start of the string index of the second
             // space character will be: 2 = 0(j) + 1(whitespace) + 1(whitespace). It is a minimal
             // possible index for the second whitespace between non-whitespace characters.
             final int minSecondWhitespaceColumnNo = 2;

             if (columnNo >= minSecondWhitespaceColumnNo
                     && !isTextSeparatedCorrectlyFromPrevious(getLine(sibling.getLineNo() - 1),
                             columnNo)) {
                 log(sibling.getLineNo(), columnNo, MSG_KEY);
             }
             if (sibling.getChildCount() >= 1) {
                 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 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));
     }

     /**
      * Checks if the {@code line} at {@code columnNo} is the end of a comment,
      * '*&#47;'.
      *
      * @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("*/");
     }
 }
	////////////////////////////////////////////////////////////////////////////////
	// 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.StatelessCheck;
	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
	*/
	@StatelessCheck
	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 getRequiredTokens();
	}

	@Override
	public int[] getAcceptableTokens() {
	return getRequiredTokens();
	}

	@Override
	public int[] getRequiredTokens() {
	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;

	// in such expression: "j =123", placed at the start of the string index of the second
	// space character will be: 2 = 0(j) + 1(whitespace) + 1(whitespace). It is a minimal
	// possible index for the second whitespace between non-whitespace characters.
	final int minSecondWhitespaceColumnNo = 2;

	if (columnNo >= minSecondWhitespaceColumnNo
	&& !isTextSeparatedCorrectlyFromPrevious(getLine(sibling.getLineNo() - 1),
	columnNo)) {
	log(sibling.getLineNo(), columnNo, MSG_KEY);
	}
	if (sibling.getChildCount() >= 1) {
	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 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));
	}

	/**
	* 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("*/");
	}
	}