Add Check Style (#92)

* Add Check Style

* Fix code smells

* Switch check style and build steps

* Fix lint

.github/workflows/on_pull_request.yml

@@ -20,6 +20,9 @@ jobs:
           distribution: 'temurin'
           cache: maven
 
+      - name: Check Style
+        run: mvn checkstyle:check
+
       - name: Build
         run: mvn clean compile
 

.github/workflows/on_push_main.yml

@@ -25,6 +25,9 @@ jobs:
           gpg-private-key: ${{ secrets.GPG_PRIVATE_KEY }}
           gpg-passphrase: MAVEN_GPG_PASSPHRASE
 
+      - name: Check Style
+        run: mvn checkstyle:check
+
       - name: Build
         id: build
         run: |

CONTRIBUTING.md

@@ -35,7 +35,32 @@ In general, we follow the ["fork-and-pull" Git workflow](https://github.com/susa
 - Push changes to your fork
 - Open a PR in our repository targeting master and follow the PR template so that we can efficiently review the changes.
 
-## Styleguides
+## Style Guide
+
+### Code Style
+
+We maintain a consistent code style using Checkstyle.
+
+#### IntelliJ
+
+To ensure code style consistency in IntelliJ, follow these steps:
+
+1. Install the [CheckStyle-IDEA plugin](https://plugins.jetbrains.com/plugin/1065-checkstyle-idea).
+2. Create a new CheckStyle configuration for Kstreamplify based on the code style configuration located in the `.checkstyle` folder. Configure it as follows:
+
+![check_style.png](.readme%2Fcontributing%2Fcheck_style.png)
+
+3. Enable the "Reformat code" and "Optimize imports" options in the save actions:
+
+![save_actions.png](.readme%2Fcontributing%2Fsave_actions.png)
+
+4. Reformat your code with the Checkstyle configuration:
+
+![reformat_code.png](.readme%2Fcontributing%2Freformat_code.png)
+
+5. Before committing your changes, ensure your contribution doesn't introduce any problems by running a scan:
+
+![scan.png](.readme%2Fcontributing%2Fscan.png)
 
 ### Git Commit Messages
 

kstreamplify-core-test/src/main/java/com/michelin/kstreamplify/KafkaStreamsStarterTest.java

@@ -7,6 +7,12 @@
 import com.michelin.kstreamplify.utils.TopicWithSerde;
 import io.confluent.kafka.schemaregistry.testutil.MockSchemaRegistry;
 import io.confluent.kafka.serializers.AbstractKafkaSchemaSerDeConfig;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.time.Instant;
+import java.util.Collections;
+import java.util.Properties;
 import org.apache.kafka.common.serialization.StringDeserializer;
 import org.apache.kafka.streams.StreamsBuilder;
 import org.apache.kafka.streams.StreamsConfig;
@@ -16,32 +22,25 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Paths;
-import java.time.Instant;
-import java.util.Collections;
-import java.util.Properties;
-
 /**
- * <p>The main test class to extend to execute unit tests on topology</p>
+ * <p>The main test class to extend to execute unit tests on topology</p>.
  * <p>It provides a {@link TopologyTestDriver} and a {@link TestOutputTopic} for the DLQ</p>
  */
 public abstract class KafkaStreamsStarterTest {
     private static final String STATE_DIR = "/tmp/kafka-streams/";
 
     /**
-     * The topology test driver
+     * The topology test driver.
      */
     protected TopologyTestDriver testDriver;
 
     /**
-     * The dlq topic, initialized in {@link #generalSetUp()}
+     * The dlq topic, initialized in {@link #generalSetUp()}.
      */
     protected TestOutputTopic<String, KafkaError> dlqTopic;
 
     /**
-     * Set up topology test driver
+     * Set up topology test driver.
      */
     @BeforeEach
     void generalSetUp() {
@@ -52,7 +51,8 @@ void generalSetUp() {
 
         KafkaStreamsExecutionContext.registerProperties(properties);
         KafkaStreamsExecutionContext.setSerdesConfig(Collections
-                .singletonMap(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, "mock://" + getClass().getName()));
+            .singletonMap(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG,
+                "mock://" + getClass().getName()));
 
         var starter = getKafkaStreamsStarter();
 
@@ -61,20 +61,22 @@ void generalSetUp() {
         StreamsBuilder streamsBuilder = new StreamsBuilder();
         starter.topology(streamsBuilder);
 
-        testDriver = new TopologyTestDriver(streamsBuilder.build(), properties, getInitialWallClockTime());
+        testDriver =
+            new TopologyTestDriver(streamsBuilder.build(), properties, getInitialWallClockTime());
 
-        dlqTopic = testDriver.createOutputTopic(KafkaStreamsExecutionContext.getDlqTopicName(), new StringDeserializer(), SerdesUtils.<KafkaError>getSerdesForValue().deserializer());
+        dlqTopic = testDriver.createOutputTopic(KafkaStreamsExecutionContext.getDlqTopicName(),
+            new StringDeserializer(), SerdesUtils.<KafkaError>getSerdesForValue().deserializer());
     }
 
     /**
-     * Method to override to provide the KafkaStreamsStarter to test
+     * Method to override to provide the KafkaStreamsStarter to test.
      *
      * @return The KafkaStreamsStarter to test
      */
     protected abstract KafkaStreamsStarter getKafkaStreamsStarter();
 
     /**
-     * Default base wall clock time for topology test driver
+     * Default base wall clock time for topology test driver.
      *
      * @return The default wall clock time as instant
      */
@@ -83,7 +85,7 @@ protected Instant getInitialWallClockTime() {
     }
 
     /**
-     * Method to close everything properly at the end of the test
+     * Method to close everything properly at the end of the test.
      */
     @AfterEach
     void generalTearDown() throws IOException {
@@ -93,26 +95,31 @@ void generalTearDown() throws IOException {
     }
 
     /**
-     * Creates an input test topic on the testDriver using the provided topicWithSerde
+     * Creates an input test topic on the testDriver using the provided topicWithSerde.
      *
      * @param topicWithSerde The topic with serde used to crete the test topic
      * @param <K>            The serializable type of the key
      * @param <V>            The serializable type of the value
      * @return The corresponding TestInputTopic
      */
-    protected <K, V> TestInputTopic<K, V> createInputTestTopic(TopicWithSerde<K, V> topicWithSerde) {
-        return this.testDriver.createInputTopic(topicWithSerde.getUnPrefixedName(), topicWithSerde.getKeySerde().serializer(), topicWithSerde.getValueSerde().serializer());
+    protected <K, V> TestInputTopic<K, V> createInputTestTopic(
+        TopicWithSerde<K, V> topicWithSerde) {
+        return this.testDriver.createInputTopic(topicWithSerde.getUnPrefixedName(),
+            topicWithSerde.getKeySerde().serializer(), topicWithSerde.getValueSerde().serializer());
     }
 
     /**
-     * Creates an output test topic on the testDriver using the provided topicWithSerde
+     * Creates an output test topic on the testDriver using the provided topicWithSerde.
      *
      * @param topicWithSerde The topic with serde used to crete the test topic
      * @param <K>            The serializable type of the key
      * @param <V>            The serializable type of the value
      * @return The corresponding TestOutputTopic
      */
-    protected <K, V> TestOutputTopic<K, V> createOutputTestTopic(TopicWithSerde<K, V> topicWithSerde) {
-        return this.testDriver.createOutputTopic(topicWithSerde.getUnPrefixedName(), topicWithSerde.getKeySerde().deserializer(), topicWithSerde.getValueSerde().deserializer());
+    protected <K, V> TestOutputTopic<K, V> createOutputTestTopic(
+        TopicWithSerde<K, V> topicWithSerde) {
+        return this.testDriver.createOutputTopic(topicWithSerde.getUnPrefixedName(),
+            topicWithSerde.getKeySerde().deserializer(),
+            topicWithSerde.getValueSerde().deserializer());
     }
 }

kstreamplify-core-test/src/test/java/com/michelin/kstreamplify/TopologyErrorHandlerTest.java

@@ -1,10 +1,13 @@
 package com.michelin.kstreamplify;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.michelin.kstreamplify.avro.KafkaError;
 import com.michelin.kstreamplify.error.ProcessingResult;
 import com.michelin.kstreamplify.error.TopologyErrorHandler;
 import com.michelin.kstreamplify.initializer.KafkaStreamsStarter;
 import com.michelin.kstreamplify.utils.SerdesUtils;
+import java.util.List;
 import org.apache.kafka.common.serialization.Serdes;
 import org.apache.kafka.common.serialization.StringDeserializer;
 import org.apache.kafka.common.serialization.StringSerializer;
@@ -17,20 +20,17 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
 class TopologyErrorHandlerTest extends KafkaStreamsStarterTest {
-    private final String AVRO_TOPIC = "avroTopic";
+    private static final String AVRO_TOPIC = "avroTopic";
+    private static final String STRING_TOPIC = "stringTopic";
+    private static final String OUTPUT_AVRO_TOPIC = "outputAvroTopic";
+    private static final String OUTPUT_STRING_TOPIC = "outputStringTopic";
+    private static final String DLQ_TOPIC = "dlqTopic";
+
     private TestInputTopic<String, KafkaError> avroInputTopic;
-    private final String STRING_TOPIC = "stringTopic";
     private TestInputTopic<String, String> stringInputTopic;
-    private final String OUTPUT_AVRO_TOPIC = "outputAvroTopic";
     private TestOutputTopic<String, KafkaError> avroOutputTopic;
-    private final String OUTPUT_STRING_TOPIC = "outputStringTopic";
     private TestOutputTopic<String, String> stringOutputTopic;
-    private final String DLQ_TOPIC = "dlqTopic";
     private TestOutputTopic<String, KafkaError> dlqTopic;
 
     @Override
@@ -44,33 +44,44 @@ public String dlqTopic() {
             @Override
             public void topology(StreamsBuilder streamsBuilder) {
                 KStream<String, ProcessingResult<String, String>> stringStream = streamsBuilder
-                        .stream(STRING_TOPIC, Consumed.with(Serdes.String(), Serdes.String()))
-                        .mapValues(value -> "error".equals(value) ?
-                                ProcessingResult.fail(new NullPointerException(), value) : ProcessingResult.success(value));
+                    .stream(STRING_TOPIC, Consumed.with(Serdes.String(), Serdes.String()))
+                    .mapValues(value -> "error".equals(value)
+                        ? ProcessingResult.fail(new NullPointerException(), value) :
+                        ProcessingResult.success(value));
 
                 TopologyErrorHandler.catchErrors(stringStream)
-                        .to(OUTPUT_STRING_TOPIC, Produced.with(Serdes.String(), Serdes.String()));
+                    .to(OUTPUT_STRING_TOPIC, Produced.with(Serdes.String(), Serdes.String()));
 
-                KStream<String, ProcessingResult<KafkaError, KafkaError>> avroStream = streamsBuilder
-                        .stream(AVRO_TOPIC, Consumed.with(Serdes.String(), SerdesUtils.<KafkaError>getSerdesForValue()))
-                        .mapValues(value -> value == null ?
-                                ProcessingResult.fail(new NullPointerException(), null) : ProcessingResult.success(value));
+                KStream<String, ProcessingResult<KafkaError, KafkaError>> avroStream =
+                    streamsBuilder
+                        .stream(AVRO_TOPIC, Consumed.with(Serdes.String(),
+                            SerdesUtils.<KafkaError>getSerdesForValue()))
+                        .mapValues(value -> value == null
+                            ? ProcessingResult.fail(new NullPointerException(), null) :
+                            ProcessingResult.success(value));
 
                 TopologyErrorHandler.catchErrors(avroStream)
-                        .to(OUTPUT_AVRO_TOPIC, Produced.with(Serdes.String(), SerdesUtils.getSerdesForValue()));
+                    .to(OUTPUT_AVRO_TOPIC,
+                        Produced.with(Serdes.String(), SerdesUtils.getSerdesForValue()));
             }
         };
     }
 
     @BeforeEach
     void setUp() {
-        stringInputTopic = testDriver.createInputTopic(STRING_TOPIC, new StringSerializer(), new StringSerializer());
-        avroInputTopic = testDriver.createInputTopic(AVRO_TOPIC, new StringSerializer(), SerdesUtils.<KafkaError>getSerdesForValue().serializer());
-
-        stringOutputTopic = testDriver.createOutputTopic(OUTPUT_STRING_TOPIC, new StringDeserializer(), new StringDeserializer());
-        avroOutputTopic = testDriver.createOutputTopic(OUTPUT_AVRO_TOPIC, new StringDeserializer(), SerdesUtils.<KafkaError>getSerdesForValue().deserializer());
-
-        dlqTopic = testDriver.createOutputTopic(DLQ_TOPIC, new StringDeserializer(), SerdesUtils.<KafkaError>getSerdesForValue().deserializer());
+        stringInputTopic = testDriver.createInputTopic(STRING_TOPIC, new StringSerializer(),
+            new StringSerializer());
+        avroInputTopic = testDriver.createInputTopic(AVRO_TOPIC, new StringSerializer(),
+            SerdesUtils.<KafkaError>getSerdesForValue().serializer());
+
+        stringOutputTopic =
+            testDriver.createOutputTopic(OUTPUT_STRING_TOPIC, new StringDeserializer(),
+                new StringDeserializer());
+        avroOutputTopic = testDriver.createOutputTopic(OUTPUT_AVRO_TOPIC, new StringDeserializer(),
+            SerdesUtils.<KafkaError>getSerdesForValue().deserializer());
+
+        dlqTopic = testDriver.createOutputTopic(DLQ_TOPIC, new StringDeserializer(),
+            SerdesUtils.<KafkaError>getSerdesForValue().deserializer());
     }
 
     @Test
@@ -86,7 +97,7 @@ void shouldContinueWhenProcessingValueIsValid() {
     }
 
     @Test
-    void shouldSendExceptionToDLQWhenProcessingValueIsInvalid() {
+    void shouldSendExceptionToDlqWhenProcessingValueIsInvalid() {
         stringInputTopic.pipeInput("key", "error");
 
         var resultDlq = dlqTopic.readValuesToList();
@@ -100,13 +111,13 @@ void shouldSendExceptionToDLQWhenProcessingValueIsInvalid() {
     void shouldContinueWhenProcessingValueIsValidAvro() {
 
         KafkaError avroModel = KafkaError.newBuilder()
-                .setTopic("topic")
-                .setStack("stack")
-                .setPartition(0)
-                .setOffset(0)
-                .setCause("cause")
-                .setValue("value")
-                .build();
+            .setTopic("topic")
+            .setStack("stack")
+            .setPartition(0)
+            .setOffset(0)
+            .setCause("cause")
+            .setValue("value")
+            .build();
 
         avroInputTopic.pipeInput("key", avroModel);
 

kstreamplify-core/src/main/java/com/michelin/kstreamplify/constants/HttpServerConstants.java

@@ -4,37 +4,37 @@
 import lombok.NoArgsConstructor;
 
 /**
- * HTTP server constants
+ * HTTP server constants.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class HttpServerConstants {
     /**
-     * Readiness probe path property name
+     * Readiness probe path property name.
      */
     public static final String READINESS_PROPERTY = "readiness_path";
 
     /**
-     * Liveness probe path property name
+     * Liveness probe path property name.
      */
     public static final String LIVENESS_PROPERTY = "liveness_path";
 
     /**
-     * Topology property name
+     * Topology property name.
      */
     public static final String TOPOLOGY_PROPERTY = "expose_topology_path";
 
     /**
-     * Readiness default path
+     * Readiness default path.
      */
     public static final String READINESS_DEFAULT_PATH = "ready";
 
     /**
-     * Liveness default path
+     * Liveness default path.
      */
     public static final String LIVENESS_DEFAULT_PATH = "liveness";
 
     /**
-     * Topology default path
+     * Topology default path.
      */
     public static final String TOPOLOGY_DEFAULT_PATH = "topology";
 }

kstreamplify-core/src/main/java/com/michelin/kstreamplify/constants/InitializerConstants.java

@@ -4,27 +4,27 @@
 import lombok.NoArgsConstructor;
 
 /**
- * Kafka Streams initialization constants
+ * Kafka Streams initialization constants.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class InitializerConstants {
     /**
-     * Server port property name
+     * Server port property name.
      */
     public static final String SERVER_PORT_PROPERTY = "server.port";
 
     /**
-     * Default host
+     * Default host.
      */
     public static final String LOCALHOST = "localhost";
 
     /**
-     * Name of the property containing of the name of the var env containing the IP
+     * Name of the property containing of the name of the var env containing the IP.
      */
     public static final String IP_SYSTEM_VARIABLE_PROPERTY = "ip.env.var.name";
 
     /**
-     * Default var env name containing the IP
+     * Default var env name containing the IP.
      */
     public static final String IP_SYSTEM_VARIABLE_DEFAULT = "MY_POD_IP";
 }