Add Apache License headers and fix code style

- Add Apache License headers to all Spark 4.0 example files
- Fix code style with spotlessApply
- Clean up ClickHouseSingleMixIn formatting

Fixes check-license CI failures.

Author: ShimonSte

clickhouse-core/src/testFixtures/scala/com/clickhouse/spark/base/ClickHouseSingleMixIn.scala

@@ -17,14 +17,15 @@ package com.clickhouse.spark.base
 import com.clickhouse.spark.Utils
 import com.clickhouse.data.ClickHouseVersion
 import com.dimafeng.testcontainers.{ForAllTestContainer, JdbcDatabaseContainer, SingleContainer}
-import org.scalatest.{BeforeAndAfterAll}
+import org.scalatest.BeforeAndAfterAll
 import org.scalatest.funsuite.AnyFunSuite
 import org.testcontainers.containers.ClickHouseContainer
 import org.testcontainers.utility.{DockerImageName, MountableFile}
 import java.nio.file.{Path, Paths}
 import scala.collection.JavaConverters._
 
-trait ClickHouseSingleMixIn extends AnyFunSuite with BeforeAndAfterAll with ForAllTestContainer with ClickHouseProvider {
+trait ClickHouseSingleMixIn extends AnyFunSuite with BeforeAndAfterAll with ForAllTestContainer
+    with ClickHouseProvider {
   // format: off
   private val CLICKHOUSE_IMAGE:    String = Utils.load("CLICKHOUSE_IMAGE", "clickhouse/clickhouse-server:23.8")
   private val CLICKHOUSE_USER:     String = Utils.load("CLICKHOUSE_USER", "default")
@@ -87,9 +88,11 @@ trait ClickHouseSingleMixIn extends AnyFunSuite with BeforeAndAfterAll with ForA
   override def beforeAll(): Unit = {
     val startTime = System.currentTimeMillis()
     println(s"[ClickHouseSingleMixIn] Starting ClickHouse container: $CLICKHOUSE_IMAGE")
-    super.beforeAll()  // This starts the container and makes mappedPort available
+    super.beforeAll() // This starts the container and makes mappedPort available
     val duration = System.currentTimeMillis() - startTime
-    println(s"[ClickHouseSingleMixIn] ClickHouse container started in ${duration}ms at ${container.host}:${container.mappedPort(CLICKHOUSE_HTTP_PORT)}")
+    println(
+      s"[ClickHouseSingleMixIn] ClickHouse container started in ${duration}ms at ${container.host}:${container.mappedPort(CLICKHOUSE_HTTP_PORT)}"
+    )
   }
 
   override def afterAll(): Unit = {

spark-4.0/examples/DEBUGGING.md

@@ -1,3 +1,17 @@
+<!--
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
 # Debugging Guide for ClickHouse Spark Connector
 
 This guide shows how to debug the connector while running the example applications.

spark-4.0/examples/SimpleBatchExample.scala

@@ -0,0 +1,13 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */

spark-4.0/examples/StreamingRateExample.scala

@@ -0,0 +1,13 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */

spark-4.0/examples/build.gradle

@@ -1,5 +1,15 @@
 /*
- * Examples module for Spark 4.0 (Scala 2.13)
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 plugins {

spark-4.0/examples/build.sbt

@@ -1,3 +1,17 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 name := "clickhouse-spark-examples"
 
 version := "1.0"

spark-4.0/examples/run-example.sh

@@ -1,5 +1,19 @@
 #!/bin/bash
 
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
 # Script to run ClickHouse Spark examples with proper classpath
 # Usage: ./run-example.sh [streaming|batch]
 # Optional env vars to override connection (must also reflect in your code or use Spark conf flags):

spark-4.0/examples/src/main/scala/examples/SimpleBatchExample.scala

@@ -48,7 +48,10 @@ object SimpleBatchExample {
       .config("spark.sql.catalog.clickhouse.password", password)
       .config("spark.sql.catalog.clickhouse.database", database)
       .config("spark.sql.catalog.clickhouse.option.ssl", (protocol == "https").toString)
-      .config("spark.executor.extraJavaOptions", "--add-opens=java.base/java.nio=org.apache.arrow.memory.core,ALL-UNNAMED")
+      .config(
+        "spark.executor.extraJavaOptions",
+        "--add-opens=java.base/java.nio=org.apache.arrow.memory.core,ALL-UNNAMED"
+      )
       .getOrCreate()
 
     spark.sparkContext.setLogLevel("WARN")