Issue checkstyle#12681: removes serializable from violation and audit…

… event

src/main/java/com/puppycrawl/tools/checkstyle/api/AuditEvent.java

@@ -19,8 +19,6 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
-import java.util.EventObject;
-
 /**
  * Raw event for audit.
  * <p>
@@ -37,11 +35,10 @@
  *
  * @see AuditListener
  */
-public final class AuditEvent
-    extends EventObject {
+public final class AuditEvent {
 
-    /** Record a version. */
-    private static final long serialVersionUID = -3774725606973812736L;
+    /** The object on which the Event initially occurred. */
+    private final Object source;
     /** Filename event associated with. **/
     private final String fileName;
     /** Violation associated with the event. **/
@@ -72,13 +69,27 @@ public AuditEvent(Object src, String fileName) {
      * @param src source of the event
      * @param fileName file associated with the event
      * @param violation the actual violation
+     * @throws IllegalArgumentException if {@code src} is {@code null}.
      */
     public AuditEvent(Object src, String fileName, Violation violation) {
-        super(src);
+        if (src == null) {
+            throw new IllegalArgumentException("null source");
+        }
+
+        source = src;
         this.fileName = fileName;
         this.violation = violation;
     }
 
+    /**
+     * The object on which the Event initially occurred.
+     *
+     * @return the object on which the Event initially occurred
+     */
+    public Object getSource() {
+        return source;
+    }
+
     /**
      * Returns name of file being audited.
      *

src/main/java/com/puppycrawl/tools/checkstyle/api/Violation.java

@@ -19,7 +19,6 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
-import java.io.Serializable;
 import java.text.MessageFormat;
 import java.util.Arrays;
 import java.util.Locale;
@@ -32,16 +31,12 @@
  * message.properties files. The underlying implementation uses
  * java.text.MessageFormat.
  *
- * @noinspection SerializableHasSerializationMethods, ClassWithTooManyConstructors
- * @noinspectionreason SerializableHasSerializationMethods - we do not serialize this class
+ * @noinspection ClassWithTooManyConstructors
  * @noinspectionreason ClassWithTooManyConstructors - immutable nature of class requires a
  *      bunch of constructors
  */
 public final class Violation
-    implements Comparable<Violation>, Serializable {
-
-    /** A unique serial version identifier. */
-    private static final long serialVersionUID = 5675176836184862150L;
+    implements Comparable<Violation> {
 
     /** The default severity level if one is not specified. */
     private static final SeverityLevel DEFAULT_SEVERITY = SeverityLevel.ERROR;
@@ -64,15 +59,7 @@ public final class Violation
     /** Key for the violation format. **/
     private final String key;
 
-    /**
-     * Arguments for MessageFormat.
-     *
-     * @noinspection NonSerializableFieldInSerializableClass
-     * @noinspectionreason NonSerializableFieldInSerializableClass - usage of
-     *      'Serializable' for this api class
-     *      is considered as mistake now, but we do not break api without
-     *      good reason
-     */
+    /** Arguments for MessageFormat. */
     private final Object[] args;
 
     /** Name of the resource bundle to get violations from. **/

src/test/java/com/puppycrawl/tools/checkstyle/api/AuditEventTest.java

@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -43,6 +44,16 @@ public void test() {
                 .isEqualTo(SeverityLevel.INFO);
     }
 
+    @Test
+    public void testNoSource() {
+        final IllegalArgumentException ex = assertThrows(IllegalArgumentException.class,
+                () -> new AuditEvent(null),
+                "IllegalArgumentException expected");
+        assertWithMessage("Invalid exception message")
+            .that(ex.getMessage())
+            .isEqualTo("null source");
+    }
+
     @Test
     public void testFullConstructor() {
         final Violation message = new Violation(1, 2, 3, "bundle", "key", null,