Implemented validate() method and covered with tests

Author: andsel

logstash-core/src/main/java/org/logstash/settings/BytesSetting.java

@@ -83,5 +83,10 @@ public Number coerce(Object obj) {
         return coerceToNumber(obj);
     }
 
-    // TODO missed validate redefinition
+    @Override
+    public void validate(Number input) throws IllegalArgumentException {
+        if (!isValid(input)) {
+            throw new IllegalArgumentException("Invalid byte value \"" + input + "\".");
+        }
+    }
 }

logstash-core/src/test/java/org/logstash/settings/BytesSettingTest.java

@@ -27,7 +27,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThrows;
 
-public class BytesSettingTest/* extends RubyTestBase*/ {
+public class BytesSettingTest {
 
     @Test
     public void givenValidStringDefaultValue_whenInstantiated_thenParsesCorrectly() {
@@ -115,4 +115,29 @@ public void testCaseInsensitiveUnits() {
         BytesSetting setting2 = new BytesSetting("test.bytes", "64mb");
         assertEquals(setting1.value(), setting2.value());
     }
+
+    @Test
+    public void givenValidInputNumberValidateSucceed() {
+        BytesSetting setting = new BytesSetting("test.bytes", "1mb");
+        // Should not throw - validation passes for positive values
+        setting.validate(1024L);
+    }
+
+    @Test
+    public void givenNullInputValidateThrowsWithSpecificMessage() {
+        BytesSetting setting = new BytesSetting("test.bytes", "1mb");
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> {
+            setting.validate(null);
+        });
+        assertThat(ex.getMessage()).isEqualTo("Invalid byte value \"null\".");
+    }
+
+    @Test
+    public void givenNegativeNumberThenValidateThrowsWithSpecificMessage() {
+        BytesSetting setting = new BytesSetting("test.bytes", "1mb");
+        IllegalArgumentException ex = assertThrows(IllegalArgumentException.class, () -> {
+            setting.validate(-100L);
+        });
+        assertThat(ex.getMessage()).isEqualTo("Invalid byte value \"-100\".");
+    }
 }