Issue checkstyle#4078: DefaultComesLast only if doesnt share case

src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/DefaultComesLastCheck.java

@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import java.util.Objects;
+
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -49,6 +51,16 @@ public class DefaultComesLastCheck extends AbstractCheck {
      */
     public static final String MSG_KEY = "default.comes.last";
 
+    /**
+     * A key is pointing to the warning message text in "messages.properties"
+     * file.
+     */
+    public static final String MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE =
+            "default.comes.last.in.casegroup";
+
+    /** Whether to process skipIfLastAndSharedWithCaseInSwitch() invocations. */
+    private boolean skipIfLastAndSharedWithCase;
+
     @Override
     public int[] getAcceptableTokens() {
         return new int[] {
@@ -66,22 +78,56 @@ public int[] getRequiredTokens() {
         return getAcceptableTokens();
     }
 
+    /**
+     * Whether to allow default keyword not in last but surrounded with case.
+     * @param newValue whether to ignore checking.
+     */
+    public void setSkipIfLastAndSharedWithCase(boolean newValue) {
+        skipIfLastAndSharedWithCase = newValue;
+    }
+
     @Override
     public void visitToken(DetailAST ast) {
         final DetailAST defaultGroupAST = ast.getParent();
         //default keywords used in annotations too - not what we're
         //interested in
         if (defaultGroupAST.getType() != TokenTypes.ANNOTATION_FIELD_DEF
                 && defaultGroupAST.getType() != TokenTypes.MODIFIERS) {
-            final DetailAST switchAST = defaultGroupAST.getParent();
-            final DetailAST lastGroupAST =
-                switchAST.getLastChild().getPreviousSibling();
 
-            if (defaultGroupAST.getLineNo() != lastGroupAST.getLineNo()
-                || defaultGroupAST.getColumnNo()
-                    != lastGroupAST.getColumnNo()) {
+            if (skipIfLastAndSharedWithCase) {
+                if (Objects.nonNull(findNextSibling(ast, TokenTypes.LITERAL_CASE))) {
+                    log(ast, MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE);
+                }
+                else if (ast.getPreviousSibling() == null
+                    && Objects.nonNull(findNextSibling(defaultGroupAST,
+                                                       TokenTypes.CASE_GROUP))) {
+                    log(ast, MSG_KEY);
+                }
+            }
+            else if (Objects.nonNull(findNextSibling(defaultGroupAST,
+                                                     TokenTypes.CASE_GROUP))) {
                 log(ast, MSG_KEY);
             }
         }
     }
+
+    /**
+     * Return token type only if passed tokenType in argument is found or returns -1.
+     *
+     * @param ast root node.
+     * @param tokenType tokentype to be processed.
+     * @return token id if desired token is not found then -1.
+     */
+    private static Object findNextSibling(DetailAST ast, int tokenType) {
+        Object token = null;
+        DetailAST node = ast.getNextSibling();
+        while (node != null) {
+            if (node.getType() == tokenType) {
+                token = node;
+                break;
+            }
+            node = node.getNextSibling();
+        }
+        return token;
+    }
 }

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages.properties

@@ -8,6 +8,7 @@ declaration.order.static=Static variable definition in wrong order.
 declaration.order.instance=Instance variable definition in wrong order.
 declaration.order.access=Variable access definition in wrong order.
 default.comes.last=Default should be last label in the switch.
+default.comes.last.in.casegroup=Default should be last label in the case group.
 empty.statement=Empty statement.
 equals.avoid.null=String literal expressions should be on the left side of an equals comparison.
 equalsIgnoreCase.avoid.null=String literal expressions should be on the left side of an equalsIgnoreCase comparison.

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_de.properties

@@ -8,6 +8,7 @@ declaration.order.static=Die statische Variable wird an der falschen Stelle dekl
 declaration.order.instance=Die Instanz-Variable wird an der falschen Stelle deklariert.
 declaration.order.access=Fehlerhafte Deklarationsreihenfolge für diesen Scope.
 default.comes.last=Der Default-Fall sollte der letzte Fall der switch-Anweisung sein.
+default.comes.last.in.casegroup=Default sollte letztes Label in der Fallgruppe sein.
 empty.statement=Leere Anweisung.
 equals.avoid.null=Bei einem equals()-Vergleich sollten String-Literale auf der linken Seite stehen.
 equalsIgnoreCase.avoid.null=Bei einem equalsIgnoreCase()-Vergleich sollten String-Literale auf der linken Seite stehen.

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_es.properties

@@ -55,6 +55,7 @@ modified.control.variable=Se modifica la variable de control ''{0}''.
 
 explicit.init=La variable ''{0}'' se inicializa explicitamente a ''{1}'' (valor por defecto para su tipo).
 default.comes.last=La etiqueta default debe ser la última etiqueta en el switch.
+default.comes.last.in.casegroup=El valor predeterminado debe ser la última etiqueta en el grupo de casos.
 missing.ctor=La clase debería definir un constructor.
 fall.through=Caída desde la etiqueta anterior en la sentencia switch.
 require.this.variable=La referencia a la variable de instancia ''{0}'' necesita \"{1}this.\".

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_fi.properties

@@ -28,6 +28,7 @@ declaration.order.static = Staattinen muuttuja määritelmä väärässä järje
 declaration.order.instance = Esimerkiksi muuttuja määritelmä väärässä järjestyksessä.
 declaration.order.access = Muuttuja pääsy määritelmä väärässä järjestyksessä.
 default.comes.last = Oletus pitäisi olla viimeinen tarra kytkin.
+default.comes.last.in.casegroup=Oletus on oltava viimeinen tarra tapauksessa ryhmässä.
 empty.statement = Tyhjä lausunto.
 equals.avoid.null = String kirjaimellinen ilmaisuja pitäisi olla vasemmalla puolella vastaa vertailun.
 equalsIgnoreCase.avoid.null = String kirjaimellinen ilmaisuja pitäisi olla vasemmalla puolella equalsIgnoreCase vertailun.

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_fr.properties

@@ -56,6 +56,7 @@ modified.control.variable=La variable de contrôle ''{0}'' est modifiée.
 
 explicit.init=L''initialisation explicite de la variable ''{0}'' à la valeur ''{1}'' est inutile, c''est la valeur par défaut pour ce type.
 default.comes.last=Le cas \"default\" devrait apparaitre en dernier dans le bloc \"switch\".
+default.comes.last.in.casegroup=La valeur par défaut doit être la dernière étiquette dans le groupe de cas.
 missing.ctor=Il manque un constructeur à la classe.
 fall.through=Le cas précédent du \"switch\" ne contient pas de break, return, throw ou continue.
 fall.through.last=Le dernier cas du \"switch\" ne contient pas de break, return, throw ou continue.

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_ja.properties

@@ -52,6 +52,7 @@ explicit.init=変数 ''{0}'' が明示的に ''{1}'' (この型のデフォル
 avoid.finalizer.method = ファイナライザメソッドを使用しないでください。
 avoid.clone.method = cloneメソッドを使用しないでください。
 default.comes.last = default は switch 文の最後のラベルにしてください。
+default.comes.last.in.casegroup=デフォルトは、ケースグループの最後のラベルにする必要があります。
 equals.avoid.null = equals による比較では、文字列リテラル式を左側にしてください。
 equalsIgnoreCase.avoid.null = equals による比較では、文字列リテラル式を左側にしてください。
 fall.through = switch 文の前の分岐からフォールスルーしています。

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_pt.properties

@@ -32,6 +32,7 @@ string.literal.equality=\"Strings\" literais devem ser comparadas com equals(),
 avoid.finalizer.method = Evite o uso de método finalizador.
 avoid.clone.method = Evite o uso de método clone.
 default.comes.last = Padrão deve ser a última etiqueta no interruptor.
+default.comes.last.in.casegroup=O padrão deve ser o último marcador no grupo de casos.
 equals.avoid.null = Corda expressões literais deve estar no lado esquerdo de um é igual comparação.
 equalsIgnoreCase.avoid.null = Corda expressões literais deve estar no lado esquerdo de uma comparação equalsIgnoreCase.
 fall.through = Queda através do ramo anterior da instrução switch.

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_tr.properties

@@ -15,6 +15,7 @@ declaration.order.instance    = Değişken tanımı yanlış sırada yapılmış
 declaration.order.static      = ''static'' değişken tanımı yanlış sırada yapılmış.
 
 default.comes.last = ''switch'' içerisindeki ''default'' ifadesi son durum olarak yer almalıdır.
+default.comes.last.in.casegroup=Varsayılan değer, vaka grubundaki son etiket olmalıdır.
 
 empty.statement = Boş ifade.
 

src/main/resources/com/puppycrawl/tools/checkstyle/checks/coding/messages_zh.properties

@@ -8,6 +8,7 @@ declaration.order.static=静态属性定义顺序错误。
 declaration.order.instance=实例属性定义顺序错误。
 declaration.order.access=属性访问器定义顺序错误。
 default.comes.last=default 应为 switch 块最后一个元素。
+default.comes.last.in.casegroup=默认值应为案例组中的最后一个标签。
 empty.statement=避免空行。
 equals.avoid.null=字符串常量应出现在 equals 比较的左侧。
 equalsIgnoreCase.avoid.null=字符串常量应出现在 equalsIgnoreCase 比较的左侧。

src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/DefaultComesLastCheckTest.java

@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
 import static com.puppycrawl.tools.checkstyle.checks.coding.DefaultComesLastCheck.MSG_KEY;
+import static com.puppycrawl.tools.checkstyle.checks.coding.DefaultComesLastCheck.MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE;
 
 import java.io.File;
 import java.io.IOException;
@@ -32,6 +33,9 @@
 import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
 
 public class DefaultComesLastCheckTest extends BaseCheckTestSupport {
+
+    private DefaultConfiguration checkConfig;
+
     @Override
     protected String getPath(String filename) throws IOException {
         return super.getPath("checks" + File.separator
@@ -44,13 +48,42 @@ protected String getNonCompilablePath(String filename) throws IOException {
                 + "coding" + File.separator + filename);
     }
 
+    @Test
+    public void testSkipIfLastAndSharedWithCase() throws Exception {
+        checkConfig = createCheckConfig(DefaultComesLastCheck.class);
+        checkConfig.addAttribute("skipIfLastAndSharedWithCase", "true");
+        final String[] expected = {
+            "17:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "25:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "33:21: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "37:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "57:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "77:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "89:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
+            "98:13: " + getCheckMessage(MSG_KEY),
+        };
+
+        verify(checkConfig, getPath("InputSkipIfLastAndSharedWithCase.java"), expected);
+    }
+
     @Test
     public void testIt() throws Exception {
-        final DefaultConfiguration checkConfig =
-            createCheckConfig(DefaultComesLastCheck.class);
+        checkConfig = createCheckConfig(DefaultComesLastCheck.class);
         final String[] expected = {
             "25:9: " + getCheckMessage(MSG_KEY),
             "32:24: " + getCheckMessage(MSG_KEY),
+            "37:13: " + getCheckMessage(MSG_KEY),
+            "45:13: " + getCheckMessage(MSG_KEY),
+            "53:13: " + getCheckMessage(MSG_KEY),
+            "61:21: " + getCheckMessage(MSG_KEY),
+            "65:13: " + getCheckMessage(MSG_KEY),
+            "69:21: " + getCheckMessage(MSG_KEY),
+            "74:13: " + getCheckMessage(MSG_KEY),
+            "85:13: " + getCheckMessage(MSG_KEY),
+            "96:13: " + getCheckMessage(MSG_KEY),
+            "106:13: " + getCheckMessage(MSG_KEY),
+            "114:13: " + getCheckMessage(MSG_KEY),
+            "125:13: " + getCheckMessage(MSG_KEY),
         };
         verify(checkConfig,
                getPath("InputDefaultComesLast.java"),
@@ -60,8 +93,7 @@ public void testIt() throws Exception {
     @Test
     public void testDefaultMethodsInJava8()
             throws Exception {
-        final DefaultConfiguration checkConfig =
-                createCheckConfig(DefaultComesLastCheck.class);
+        checkConfig = createCheckConfig(DefaultComesLastCheck.class);
         final String[] expected = CommonUtils.EMPTY_STRING_ARRAY;
         verify(checkConfig,
                 getPath("InputDefaultComesLast2.java"),

src/test/resources/com/puppycrawl/tools/checkstyle/checks/coding/InputDefaultComesLast.java

@@ -31,6 +31,104 @@ void method(int i) {
         switch (i) {
         case 1: break; default: break; case 2: break;  
         }
+
+        switch (i) {
+            case 1:
+            default: //violation
+                break;
+            case 2:
+                break;
+        }
+
+        switch (i) {
+            case 1:
+            default: //violation
+            case 2:
+                break;
+            case 3:
+                break;
+        }
+
+        switch (i) {
+            default: //violation
+            case 1:
+                break;
+            case 2:
+                break;
+        }
+
+        switch (i) {
+            case 0: default: case 1: break; case 2: break; //violation
+        }
+
+        switch (i) {
+            default: case 1: break; case 2: break; //violation
+        }
+
+        switch (i) {
+            case 1: default: break; case 2: break; //violation
+        }
+
+        switch (i) {
+            case 1:
+            default: //violation
+                break;
+            case 2:
+                break;
+            case 3:
+                break;
+        }
+
+        switch (i) {
+            case 1:
+                break;
+            default: //violation
+            case 2:
+                break;
+            case 3:
+                break;
+        }
+
+        switch (i) {
+            case 1:
+                break;
+            case 2:
+            default: //violation
+                break;
+            case 3:
+                break;
+        }
+
+        switch (i) {
+            case 1:
+                break;
+            case 2:
+            default: //violation
+            case 3:
+                break;
+            case 4:
+                break;
+        }
+
+        switch (i) {
+            default: //violation
+                break;
+            case 1:
+                break;
+        }
+
+        switch (i) {
+            case 1:
+                break;
+            case 2:
+                break;
+            default: //violation
+            case 5:
+            case 6:
+                break;
+            case 7:
+                break;
+        }
     }
 }