001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2016 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.javadoc;
021
022import java.util.regex.Pattern;
023
024import com.google.common.base.CharMatcher;
025import com.puppycrawl.tools.checkstyle.api.DetailNode;
026import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
027import com.puppycrawl.tools.checkstyle.api.TokenTypes;
028import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
029import com.puppycrawl.tools.checkstyle.utils.JavadocUtils;
030
031/**
032 * <p>
033 * Checks that <a href=
034 * "http://www.oracle.com/technetwork/java/javase/documentation/index-137868.html#firstsentence">
035 * Javadoc summary sentence</a> does not contain phrases that are not recommended to use.
036 * By default Check validate that first sentence is not empty:</p><br>
037 * <pre>
038 * &lt;module name=&quot;SummaryJavadocCheck&quot;/&gt;
039 * </pre>
040 *
041 * <p>To ensure that summary do not contain phrase like "This method returns",
042 *  use following config:
043 *
044 * <pre>
045 * &lt;module name=&quot;SummaryJavadocCheck&quot;&gt;
046 *     &lt;property name=&quot;forbiddenSummaryFragments&quot;
047 *     value=&quot;^This method returns.*&quot;/&gt;
048 * &lt;/module&gt;
049 * </pre>
050 * <p>
051 * To specify period symbol at the end of first javadoc sentence - use following config:
052 * </p>
053 * <pre>
054 * &lt;module name=&quot;SummaryJavadocCheck&quot;&gt;
055 *     &lt;property name=&quot;period&quot;
056 *     value=&quot;period&quot;/&gt;
057 * &lt;/module&gt;
058 * </pre>
059 *
060 *
061 * @author max
062 * @author <a href="mailto:nesterenko-aleksey@list.ru">Aleksey Nesterenko</a>
063 */
064public class SummaryJavadocCheck extends AbstractJavadocCheck {
065
066    /**
067     * A key is pointing to the warning message text in "messages.properties"
068     * file.
069     */
070    public static final String MSG_SUMMARY_FIRST_SENTENCE = "summary.first.sentence";
071
072    /**
073     * A key is pointing to the warning message text in "messages.properties"
074     * file.
075     */
076    public static final String MSG_SUMMARY_JAVADOC = "summary.javaDoc";
077    /**
078     * This regexp is used to convert multiline javadoc to single line without stars.
079     */
080    private static final Pattern JAVADOC_MULTILINE_TO_SINGLELINE_PATTERN =
081            Pattern.compile("\n[ ]+(\\*)|^[ ]+(\\*)");
082
083    /** Period literal. */
084    private static final String PERIOD = ".";
085
086    /**
087     * Regular expression for forbidden summary fragments.
088     */
089    private Pattern forbiddenSummaryFragments = CommonUtils.createPattern("^$");
090
091    /**
092     * Period symbol at the end of first javadoc sentence.
093     */
094    private String period = PERIOD;
095
096    /**
097     * Sets custom value of regular expression for forbidden summary fragments.
098     * @param pattern user's value.
099     */
100    public void setForbiddenSummaryFragments(String pattern) {
101        forbiddenSummaryFragments = CommonUtils.createPattern(pattern);
102    }
103
104    /**
105     * Sets value of period symbol at the end of first javadoc sentence.
106     * @param period period's value.
107     */
108    public void setPeriod(String period) {
109        this.period = period;
110    }
111
112    @Override
113    public int[] getDefaultJavadocTokens() {
114        return new int[] {
115            JavadocTokenTypes.JAVADOC,
116        };
117    }
118
119    @Override
120    public int[] getAcceptableTokens() {
121        return new int[] {TokenTypes.BLOCK_COMMENT_BEGIN };
122    }
123
124    @Override
125    public int[] getRequiredTokens() {
126        return getAcceptableTokens();
127    }
128
129    @Override
130    public void visitJavadocToken(DetailNode ast) {
131        String firstSentence = getFirstSentence(ast);
132        final int endOfSentence = firstSentence.lastIndexOf(period);
133        if (endOfSentence == -1) {
134            if (!firstSentence.trim().startsWith("{@inheritDoc}")) {
135                log(ast.getLineNumber(), MSG_SUMMARY_FIRST_SENTENCE);
136            }
137        }
138        else {
139            firstSentence = firstSentence.substring(0, endOfSentence);
140            if (containsForbiddenFragment(firstSentence)) {
141                log(ast.getLineNumber(), MSG_SUMMARY_JAVADOC);
142            }
143        }
144    }
145
146    /**
147     * Finds and returns first sentence.
148     * @param ast Javadoc root node.
149     * @return first sentence.
150     */
151    private static String getFirstSentence(DetailNode ast) {
152        final StringBuilder result = new StringBuilder();
153        final String periodSuffix = PERIOD + ' ';
154        for (DetailNode child : ast.getChildren()) {
155            if (child.getType() != JavadocTokenTypes.JAVADOC_INLINE_TAG
156                && child.getText().contains(periodSuffix)) {
157                result.append(getCharsTillDot(child));
158                break;
159            }
160            else {
161                result.append(child.getText());
162            }
163        }
164        return result.toString();
165    }
166
167    /**
168     * Finds and returns chars till first dot.
169     * @param textNode node with javadoc text.
170     * @return String with chars till first dot.
171     */
172    private static String getCharsTillDot(DetailNode textNode) {
173        final StringBuilder result = new StringBuilder();
174        for (DetailNode child : textNode.getChildren()) {
175            result.append(child.getText());
176            if (PERIOD.equals(child.getText())
177                && JavadocUtils.getNextSibling(child).getType() == JavadocTokenTypes.WS) {
178                break;
179            }
180        }
181        return result.toString();
182    }
183
184    /**
185     * Tests if first sentence contains forbidden summary fragment.
186     * @param firstSentence String with first sentence.
187     * @return true, if first sentence contains forbidden summary fragment.
188     */
189    private boolean containsForbiddenFragment(String firstSentence) {
190        String javadocText = JAVADOC_MULTILINE_TO_SINGLELINE_PATTERN
191                .matcher(firstSentence).replaceAll(" ");
192        javadocText = CharMatcher.WHITESPACE.trimAndCollapseFrom(javadocText, ' ');
193        return forbiddenSummaryFragments.matcher(javadocText).find();
194    }
195}