Issue checkstyle#3908: SummaryJavadoc need special processing of inhe…

…ritDoc tag

src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheck.java

@@ -78,9 +78,15 @@ public class SummaryJavadocCheck extends AbstractJavadocCheck {
      */
     private static final Pattern JAVADOC_MULTILINE_TO_SINGLELINE_PATTERN =
             Pattern.compile("\n[ ]+(\\*)|^[ ]+(\\*)");
-
+    /**
+     * This regexp is used to find occurence of first character of asteric.
+     */
+    private static final Pattern FIRST_CHARACTER_ASTERIC_PATTERN =
+            Pattern.compile("^\\*");
     /** Period literal. */
     private static final String PERIOD = ".";
+    /** Inherit doc literal. */
+    private static final String INHERIT_DOC_LITERAL = "{@inheritDoc}";
 
     /**
      * Regular expression for forbidden summary fragments.
@@ -135,9 +141,12 @@ public void visitJavadocToken(DetailNode ast) {
         String firstSentence = getFirstSentence(ast);
         final int endOfSentence = firstSentence.lastIndexOf(period);
         if (endOfSentence == -1) {
-            if (!firstSentence.trim().startsWith("{@inheritDoc}")) {
+            if (!firstSentence.trim().startsWith(INHERIT_DOC_LITERAL)
+             && !FIRST_CHARACTER_ASTERIC_PATTERN.matcher(firstSentence.trim())
+             .replaceFirst("").trim().startsWith(INHERIT_DOC_LITERAL)
+             && !isValidAInheritDocAfterRemovingAsteric(firstSentence)) {
                 log(ast.getLineNumber(), MSG_SUMMARY_FIRST_SENTENCE);
-            }
+             }
         }
         else {
             firstSentence = firstSentence.substring(0, endOfSentence);
@@ -147,6 +156,31 @@ public void visitJavadocToken(DetailNode ast) {
         }
     }
 
+    /**
+     * Removes asteric from start and end of sentence and determines sentence contains {@inheritDoc}
+     * @param firstSentence -first sentence of comment
+     * @return true if valid and false if invalid content in sentence.
+     */
+    private boolean isValidAInheritDocAfterRemovingAsteric(String firstSentence) {
+        int begin = firstSentence.indexOf(INHERIT_DOC_LITERAL);
+        boolean result =true;
+        if(begin == -1) {
+            result = false;
+        }
+        StringBuilder innerContent = new StringBuilder();
+        for (int index = 0 ; index <= begin && result ; index++) {
+            if(firstSentence.charAt(index) != '*' || firstSentence.charAt(index) != ' '
+                    || firstSentence.charAt(index) != '\n') {
+                innerContent.append(firstSentence.charAt(index));
+            }
+        }
+        if(innerContent.equals(INHERIT_DOC_LITERAL)) {
+            result = true;
+        }
+
+        return result;
+    }
+
     /**
      * Finds and returns first sentence.
      * @param ast Javadoc root node.

src/test/resources/com/puppycrawl/tools/checkstyle/checks/javadoc/InputCorrectSummaryJavaDoc.java

@@ -32,6 +32,15 @@ void foo6() {}
     /** {@inheritDoc} */
     void foo7() {}
 
+    /**
+     * {@inheritDoc} */
+    void foo8() {}
+
+    /**
+     * {@inheritDoc}
+     */
+    void foo9() {}
+
     /** 
      * <a href="mailto:vlad@htmlbook.ru"/> 
      */