ThrowCountCheck should have option to skip private methods, #1136

src/main/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheck.java

@@ -41,6 +41,10 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  * a caller but allows any sub-classes to be caught
  * specifically if necessary.
  * </p>
+ * <p>
+ * <b>ignorePrivateMethods</b> - allows to skip private methods as they do
+ * not cause problems for other classes.
+ * </p>
  * @author <a href="mailto:simon@redhillconsulting.com.au">Simon Harris</a>
  */
 public final class ThrowsCountCheck extends Check {
@@ -54,6 +58,9 @@ public final class ThrowsCountCheck extends Check {
     /** default value of max property */
     private static final int DEFAULT_MAX = 1;
 
+    /** whether private methods must be ignored **/
+    private boolean ignorePrivateMethods = true;
+
     /** maximum allowed throws statements */
     private int max;
 
@@ -89,6 +96,14 @@ public final class ThrowsCountCheck extends Check {
         return max;
     }
 
+    /**
+     * Sets whether private methods must be ignored.
+     * @param ignorePrivateMethods whether private methods must be ignored.
+     */
+    public void setIgnorePrivateMethods(boolean ignorePrivateMethods) {
+        this.ignorePrivateMethods = ignorePrivateMethods;
+    }
+
     /**
      * Setter for max property.
      * @param max maximum allowed throws statements.
@@ -112,7 +127,8 @@ public final class ThrowsCountCheck extends Check {
      * @param ast throws for check.
      */
     private void visitLiteralThrows(DetailAST ast) {
-        if (!isOverriding(ast)) {
+        if ((!ignorePrivateMethods || !isInPrivateMethod(ast))
+                && !isOverriding(ast)) {
             // Account for all the commas!
             final int count = (ast.getChildCount() + 1) / 2;
             if (count > getMax()) {
@@ -159,4 +175,14 @@ public final class ThrowsCountCheck extends Check {
         }
         return name;
     }
+
+    /**
+     * Checks if method, which throws an exception is private.
+     * @param ast throws, which is being checked.
+     * @return true, if method, which throws an exception is private.
+     */
+    private static boolean isInPrivateMethod(DetailAST ast) {
+        final DetailAST methodModifiers = ast.getParent().findFirstToken(TokenTypes.MODIFIERS);
+        return methodModifiers.findFirstToken(TokenTypes.LITERAL_PRIVATE) != null;
+    }
 }

src/test/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheckTest.java

@@ -45,7 +45,7 @@ public class ThrowsCountCheckTest extends BaseCheckTestSupport {
             "14:20: " + getCheckMessage(MSG_KEY, 2, 1),
             "18:20: " + getCheckMessage(MSG_KEY, 2, 1),
             "22:20: " + getCheckMessage(MSG_KEY, 3, 1),
-            "45:43: " + getCheckMessage(MSG_KEY, 2, 1),
+            "48:43: " + getCheckMessage(MSG_KEY, 2, 1),
         };
 
         verify(checkConfig, getPath("design" + File.separator + "InputThrowsCount.java"), expected);
@@ -90,4 +90,18 @@ public class ThrowsCountCheckTest extends BaseCheckTestSupport {
             assertEquals(ast.toString(), e.getMessage());
         }
     }
+
+    @Test
+    public void testNotIgnorePrivateMethod() throws Exception {
+        DefaultConfiguration checkConfig = createCheckConfig(ThrowsCountCheck.class);
+        checkConfig.addAttribute("ignorePrivateMethods", "false");
+        String[] expected = {
+            "14:20: " + getCheckMessage(MSG_KEY, 2, 1),
+            "18:20: " + getCheckMessage(MSG_KEY, 2, 1),
+            "22:20: " + getCheckMessage(MSG_KEY, 3, 1),
+            "29:28: " + getCheckMessage(MSG_KEY, 3, 1),
+            "48:43: " + getCheckMessage(MSG_KEY, 2, 1),
+        };
+        verify(checkConfig, getPath("design" + File.separator + "InputThrowsCount.java"), expected);
+    }
 }

src/test/resources/com/puppycrawl/tools/checkstyle/design/InputThrowsCount.java

@@ -25,6 +25,9 @@ public class InputThrowsCount {
 
     void method6() {
     }
+    
+    private void method7() throws Exception, AWTException, Throwable {
+    }
 }
 
 class SubClass extends InputThrowsCount {

src/xdocs/config_design.xml

@@ -591,6 +591,11 @@ public class StringUtils // not final to allow subclassing
           type of exception need be checked for by a caller but any
           subclasses can be caught specifically if necessary.
         </p>
+
+        <p>
+          <b>ignorePrivateMethods</b> - allows to skip private methods as they do
+          not cause problems for other classes.
+        </p>
       </subsection>
 
       <subsection name="Properties">
@@ -607,6 +612,12 @@ public class StringUtils // not final to allow subclassing
             <td><a href="property_types.html#integer">Integer</a></td>
             <td><code>1</code></td>
           </tr>
+          <tr>
+            <td>ignorePrivateMethods</td>
+            <td>whether private methods must be ignored</td>
+            <td><a href="property_types.html#boolean">Boolean</a></td>
+            <td><code>true</code></td>
+          </tr>
         </table>
       </subsection>
 
@@ -618,6 +629,15 @@ public class StringUtils // not final to allow subclassing
         <source>
 &lt;module name=&quot;ThrowsCount&quot;&gt;
     &lt;property name=&quot;max&quot; value=&quot;2&quot;/&gt;
+&lt;/module&gt;
+        </source>
+
+        <p>
+          To configure the check so that it doesn't skip private methods:
+        </p>
+        <source>
+&lt;module name=&quot;ThrowsCount&quot;&gt;
+    &lt;property name=&quot;ignorePrivateMethods&quot; value=&quot;false&quot;/&gt;
 &lt;/module&gt;
         </source>
       </subsection>