com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocContentLocationCheck Maven / Gradle / Ivy
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Checkstyle is a development tool to help programmers write Java code
that adheres to a coding standard
////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2020 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.javadoc;
import java.util.Locale;
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;
import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
/**
*
* Checks that the Javadoc content begins from the same position
* for all Javadoc comments in the project. Any leading asterisks and spaces
* are not counted as the beginning of the content and are therefore ignored.
*
*
* It is possible to enforce two different styles:
*
*
* -
* {@code first_line} - Javadoc content starts from the first line:
*
* /** Summary text.
* * More details.
* */
* public void method();
*
*
* -
* {@code second_line} - Javadoc content starts from the second line:
*
* /**
* * Summary text.
* * More details.
* */
* public void method();
*
*
*
*
* This check does not validate the Javadoc summary itself nor its presence.
* The check will not report any violations for missing or malformed javadoc summary.
* To validate the Javadoc summary use
* SummaryJavadoc check.
*
*
* The
* Documentation Comment Specification permits leading asterisks on the first line.
* For these Javadoc comments:
*
*
* /***
* * Some text.
* */
* /************
* * Some text.
* */
* /** **
* * Some text.
* */
*
*
* The documentation generated will be just "Some text." without any asterisks.
* Since these asterisks will not appear in the generated documentation,
* they should not be considered as the beginning of the Javadoc content.
* In such cases, the check assumes that the Javadoc content begins on the second line.
*
*
* -
* Property {@code location} - Specify the policy on placement of the Javadoc content.
* Default value is {@code second_line}.
*
*
*
* By default Check validate that the Javadoc content starts from the second line:
*
*
* <module name="JavadocContentLocationCheck"/>
*
*
* This setting produces a violation for each multi-line comment starting
* on the same line as the initial asterisks:
*
*
* /** This comment causes a violation because it starts from the first line
* * and spans several lines.
* */
* /**
* * This comment is OK because it starts from the second line.
* */
* /** This comment is OK because it is on the single line. */
*
*
* To ensure that Javadoc content starts from the first line:
*
*
* <module name="JavadocContentLocationCheck">
* <property name="location" value="first_line"/>
* </module>
*
*
* This setting produces a violation for each comment not
* starting on the same line as the initial asterisks:
*
*
* /** This comment is OK because it starts on the first line.
* * There may be additional text.
* */
* /**
* * This comment causes a violation because it starts on the second line.
* */
* /** This single-line comment also is OK. */
*
*
* @since 8.27
*/
@StatelessCheck
public class JavadocContentLocationCheck extends AbstractCheck {
/**
* A key is pointing to the warning message text in "messages.properties" file.
*/
public static final String MSG_JAVADOC_CONTENT_FIRST_LINE = "javadoc.content.first.line";
/**
* A key is pointing to the warning message text in "messages.properties" file.
*/
public static final String MSG_JAVADOC_CONTENT_SECOND_LINE = "javadoc.content.second.line";
/**
* Specify the policy on placement of the Javadoc content.
*/
private JavadocContentLocationOption location = JavadocContentLocationOption.SECOND_LINE;
@Override
public int[] getRequiredTokens() {
return new int[] {
TokenTypes.BLOCK_COMMENT_BEGIN,
};
}
@Override
public int[] getAcceptableTokens() {
return getRequiredTokens();
}
@Override
public int[] getDefaultTokens() {
return getRequiredTokens();
}
@Override
public boolean isCommentNodesRequired() {
return true;
}
/**
* Setter to specify the policy on placement of the Javadoc content.
*
* @param value string to decode location from
* @throws IllegalArgumentException if unable to decode
*/
public void setLocation(String value) {
location = JavadocContentLocationOption.valueOf(value.trim().toUpperCase(Locale.ENGLISH));
}
@Override
public void visitToken(DetailAST ast) {
if (isMultilineComment(ast) && JavadocUtil.isJavadocComment(ast)) {
final String commentContent = JavadocUtil.getJavadocCommentContent(ast);
final int indexOfFirstNonBlankLine = findIndexOfFirstNonBlankLine(commentContent);
if (indexOfFirstNonBlankLine >= 0) {
if (location == JavadocContentLocationOption.FIRST_LINE) {
if (indexOfFirstNonBlankLine != 0) {
log(ast, MSG_JAVADOC_CONTENT_FIRST_LINE);
}
}
else if (indexOfFirstNonBlankLine != 1) {
log(ast, MSG_JAVADOC_CONTENT_SECOND_LINE);
}
}
}
}
/**
* Checks if a DetailAST of type {@code TokenTypes.BLOCK_COMMENT_BEGIN} span
* more than one line. The node always has at least one child of the type
* {@code TokenTypes.BLOCK_COMMENT_END}.
*
* @param node node to check
* @return {@code true} for multi-line comment nodes
*/
private static boolean isMultilineComment(DetailAST node) {
return !TokenUtil.areOnSameLine(node, node.getLastChild());
}
/**
* Returns the index of the first non-blank line.
* All lines consists only of asterisks and whitespaces are treated as blank.
*
* @param commentContent Javadoc content to process
* @return the index of the first non-blank line or {@code -1} if all lines are blank
*/
private static int findIndexOfFirstNonBlankLine(String commentContent) {
int lineNo = 0;
boolean noContent = true;
for (int i = 0; i < commentContent.length(); ++i) {
final char character = commentContent.charAt(i);
if (character == '\n') {
++lineNo;
}
else if (character != '*' && !Character.isWhitespace(character)) {
noContent = false;
break;
}
}
if (noContent) {
lineNo = -1;
}
return lineNo;
}
}