Issue #3322: added RedundantModifiers for final in abstract methods

src/main/java/com/puppycrawl/tools/checkstyle/checks/modifier/RedundantModifierCheck.java

@@ -141,25 +141,28 @@ public class RedundantModifierCheck
         if (ast.getType() == TokenTypes.INTERFACE_DEF) {
             checkInterfaceModifiers(ast);
         }
-        else if (ast.getType() == TokenTypes.CTOR_DEF) {
-            if (isEnumMember(ast)) {
-                checkEnumConstructorModifiers(ast);
-            }
-            else {
-                checkClassConstructorModifiers(ast);
-            }
-        }
         else if (ast.getType() == TokenTypes.ENUM_DEF) {
             checkEnumDef(ast);
         }
-        else if (isInterfaceOrAnnotationMember(ast)) {
-            processInterfaceOrAnnotation(ast);
-        }
-        else if (ast.getType() == TokenTypes.METHOD_DEF) {
-            processMethods(ast);
-        }
-        else if (ast.getType() == TokenTypes.RESOURCE) {
-            processResources(ast);
+        else {
+            if (ast.getType() == TokenTypes.CTOR_DEF) {
+                if (isEnumMember(ast)) {
+                    checkEnumConstructorModifiers(ast);
+                }
+                else {
+                    checkClassConstructorModifiers(ast);
+                }
+            }
+            else if (ast.getType() == TokenTypes.METHOD_DEF) {
+                processMethods(ast);
+            }
+            else if (ast.getType() == TokenTypes.RESOURCE) {
+                processResources(ast);
+            }
+
+            if (isInterfaceOrAnnotationMember(ast)) {
+                processInterfaceOrAnnotation(ast);
+            }
         }
     }
 
@@ -203,12 +206,7 @@ public class RedundantModifierCheck
             processInterfaceOrAnnotation(ast);
         }
         else if (ast.getParent() != null) {
-            final DetailAST modifiers = ast.findFirstToken(TokenTypes.MODIFIERS);
-            final DetailAST staticModifier = modifiers.findFirstToken(TokenTypes.LITERAL_STATIC);
-            if (staticModifier != null) {
-                log(staticModifier.getLineNo(), staticModifier.getColumnNo(),
-                        MSG_KEY, staticModifier.getText());
-            }
+            checkForRedundantModifier(ast, TokenTypes.LITERAL_STATIC);
         }
     }
 
@@ -243,7 +241,7 @@ public class RedundantModifierCheck
     }
 
     /**
-     * Process validation ofMethods.
+     * Process validation of Methods.
      * @param ast method AST
      */
     private void processMethods(DetailAST ast) {
@@ -270,15 +268,25 @@ public class RedundantModifierCheck
             }
         }
         if (checkFinal && !isAnnotatedWithSafeVarargs(ast)) {
-            DetailAST modifier = modifiers.getFirstChild();
-            while (modifier != null) {
-                final int type = modifier.getType();
-                if (type == TokenTypes.FINAL) {
-                    log(modifier.getLineNo(), modifier.getColumnNo(),
-                            MSG_KEY, modifier.getText());
-                    break;
-                }
-                modifier = modifier.getNextSibling();
+            checkForRedundantModifier(ast, TokenTypes.FINAL);
+        }
+
+        if (!ast.branchContains(TokenTypes.SLIST)) {
+            processAbstractMethodParameters(ast);
+        }
+    }
+
+    /**
+     * Process validation of parameters for Methods with no definition.
+     * @param ast method AST
+     */
+    private void processAbstractMethodParameters(DetailAST ast) {
+        final DetailAST parameters = ast.findFirstToken(TokenTypes.PARAMETERS);
+
+        for (DetailAST child = parameters.getFirstChild(); child != null; child = child
+                .getNextSibling()) {
+            if (child.getType() == TokenTypes.PARAMETER_DEF) {
+                checkForRedundantModifier(child, TokenTypes.FINAL);
             }
         }
     }
@@ -290,7 +298,7 @@ public class RedundantModifierCheck
     private void checkClassConstructorModifiers(DetailAST classCtorAst) {
         final DetailAST classDef = classCtorAst.getParent().getParent();
         if (!isClassPublic(classDef) && !isClassProtected(classDef)) {
-            checkForRedundantPublicModifier(classCtorAst);
+            checkForRedundantModifier(classCtorAst, TokenTypes.LITERAL_PUBLIC);
         }
     }
 
@@ -299,30 +307,19 @@ public class RedundantModifierCheck
      * @param ast ast
      */
     private void processResources(DetailAST ast) {
-        final DetailAST modifiers = ast.findFirstToken(TokenTypes.MODIFIERS);
-        DetailAST modifier = modifiers.getFirstChild();
-
-        while (modifier != null) {
-            final int type = modifier.getType();
-
-            if (type == TokenTypes.FINAL) {
-                log(modifier.getLineNo(), modifier.getColumnNo(), MSG_KEY, modifier.getText());
-                break;
-            }
-
-            modifier = modifier.getNextSibling();
-        }
+        checkForRedundantModifier(ast, TokenTypes.FINAL);
     }
 
     /**
-     * Checks if given ast has redundant public modifier.
+     * Checks if given ast has a redundant modifier.
      * @param ast ast
+     * @param modifierType The modifier to check for.
      */
-    private void checkForRedundantPublicModifier(DetailAST ast) {
+    private void checkForRedundantModifier(DetailAST ast, int modifierType) {
         final DetailAST astModifiers = ast.findFirstToken(TokenTypes.MODIFIERS);
         DetailAST astModifier = astModifiers.getFirstChild();
         while (astModifier != null) {
-            if (astModifier.getType() == TokenTypes.LITERAL_PUBLIC) {
+            if (astModifier.getType() == modifierType) {
                 log(astModifier.getLineNo(), astModifier.getColumnNo(),
                         MSG_KEY, astModifier.getText());
             }

src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/RedundantModifierCheckTest.java

@@ -210,4 +210,17 @@ public class RedundantModifierCheckTest
         };
         verify(checkConfig, getPath("InputFinalInTryWithResource.java"), expected);
     }
+
+    @Test
+    public void testFinalInAbstractMethods() throws Exception {
+        final DefaultConfiguration checkConfig = createCheckConfig(RedundantModifierCheck.class);
+        final String[] expected = {
+            "4:33: " + getCheckMessage(MSG_KEY, "final"),
+            "8:49: " + getCheckMessage(MSG_KEY, "final"),
+            "11:17: " + getCheckMessage(MSG_KEY, "final"),
+            "16:24: " + getCheckMessage(MSG_KEY, "final"),
+            "25:33: " + getCheckMessage(MSG_KEY, "final"),
+        };
+        verify(checkConfig, getPath("InputFinalInAbstractMethods.java"), expected);
+    }
 }

src/test/resources/com/puppycrawl/tools/checkstyle/checks/modifier/InputFinalInAbstractMethods.java

@@ -0,0 +1,26 @@
+package com.puppycrawl.tools.checkstyle.checks.modifier;
+
+public abstract class InputFinalInAbstractMethods {
+    public abstract void method(final String param); // violation
+
+    public abstract void method2(String param);
+
+    public abstract void method3(String param1, final String param2); // violation
+}
+interface IWhatever {
+    void method(final String param); // violation
+
+    void method2(String param);
+}
+class CWhatever {
+    native void method(final String param); // violation
+
+    native void method2(String param);
+}
+enum EWhatever {
+    TEST() {
+        public void method(String s) {};
+    };
+
+    public abstract void method(final String s); // violation
+}