feat: review Comments

Address the review comments

Also adjusted the build so it was connected to the main top level build
(resulted in removing quite a bit of the gradle build that really wasn't needed here)

Converted to Kotlin format (hopefully corectly)

Signed-off-by: MBWhite <[email protected]>

Author: mbwhite

.gitignore

@@ -9,3 +9,5 @@ out/**
 *.iws
 .vscode
 .pmdCache
+
+*/bin

examples/substrait-spark/.gitignore

@@ -1,2 +1,4 @@
+spark-warehouse
+derby.log
 _apps
 _data

examples/substrait-spark/README.md

@@ -1,7 +1,6 @@
 # Introduction to the Substrait-Spark library
 
-The Substrait-Spark library was recently added to the [substrait-java](https://github.com/substrait-io/substrait-java) project; this library allows Substrait plans to convert to and from Spark Plans.
-
+The Substrait-Spark library allows Substrait plans to convert to and from Spark Plans. This example will show how this can be used.
 
 ## How does this work in practice?
 
@@ -27,7 +26,7 @@ To run these you will need:
 - Java 17 or greater
 - Docker to start a test Spark Cluster
   - you could use your own cluster, but would need to adjust file locations defined in [SparkHelper](./app/src/main/java/io/substrait/examples/SparkHelper.java)
-- [just task runner](https://github.com/casey/just#installation) optional, but very helpful to run the bash commands
+- The [just task runner](https://github.com/casey/just#installation) is optional, but very helpful to run the bash commands
 - [Two datafiles](./app/src/main/resources/) are provided (CSV format)
 
 For building using the `substrait-spark` library youself, using the [mvn repository](https://mvnrepository.com/artifact/io.substrait/spark)

examples/substrait-spark/app/.gitignore

@@ -0,0 +1,44 @@
+
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id("java")
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+    implementation("org.apache.spark:spark-core_2.12:3.5.1")
+    implementation("io.substrait:spark:0.36.0")
+    implementation("io.substrait:core:0.36.0")
+    implementation("org.apache.spark:spark-sql_2.12:3.5.1")
+
+    // For a real Spark application, these would not be required since they would be in the Spark server classpath
+    runtimeOnly("org.apache.spark:spark-core_2.12:3.5.1")
+    runtimeOnly("org.apache.spark:spark-hive_2.12:3.5.1")
+
+}
+
+tasks.jar {
+    isZip64 = true
+    exclude ("META-INF/*.RSA")
+    exclude ("META-INF/*.SF")
+    exclude ("META-INF/*.DSA")
+
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    manifest.attributes["Main-Class"] = "io.substrait.examples.App"
+    from(configurations.runtimeClasspath.get().map({ if (it.isDirectory) it else zipTree(it) }))
+
+}
+
+tasks.named<Test>("test") {
+    // Use JUnit Platform for unit tests.
+    useJUnitPlatform()
+}
+
+java {
+  toolchain { languageVersion.set(JavaLanguageVersion.of(17)) }
+}
+