finos#1318 improve ExternalEntitySchema api and add a toMap method

- this change also removes getListToObjectConverter.scala since
  its api isn't Java friendly, and it assumes the passed values
  are in the same order as the class' constructor params. Which
  might not always be the case.
- replaced it with a more flexible solution with JsonMapper, that
  converts a map (of field names->values) to a class instance. Which
  should be easily replicable in  Java.

example/apache-ignite/src/main/scala/org/finos/vuu/example/ignite/IgniteOrderStore.scala

@@ -6,7 +6,7 @@ import org.apache.ignite.cache.query._
 import org.apache.ignite.cluster.ClusterState
 import org.apache.ignite.{IgniteCache, Ignition}
 import org.finos.vuu.core.module.simul.model.{ChildOrder, OrderStore, ParentOrder}
-import org.finos.vuu.example.ignite.utils.getListToObjectConverter
+import org.finos.vuu.example.ignite.schema.ChildOrderSchema.toChildOrder
 import org.finos.vuu.feature.ignite.IgniteSqlQuery
 import org.finos.vuu.feature.ignite.IgniteSqlQuery.QuerySeparator
 
@@ -143,8 +143,6 @@ class IgniteOrderStore(private val parentOrderCache: IgniteCache[Int, ParentOrde
       .map(x => x.getValue)
   }
 
-  private def toChildOrder = getListToObjectConverter[ChildOrder](ChildOrder)
-
   private def mapToString(results: FieldsQueryCursor[util.List[_]]): (Int, ListBuffer[String]) = {
     var counter = 0
     val buffer = mutable.ListBuffer[String]()

example/apache-ignite/src/main/scala/org/finos/vuu/example/ignite/schema/ChildOrderSchema.scala

@@ -1,5 +1,7 @@
 package org.finos.vuu.example.ignite.schema
 
+import com.fasterxml.jackson.databind.json.JsonMapper
+import com.fasterxml.jackson.module.scala.{ClassTagExtensions, DefaultScalaModule}
 import org.apache.ignite.cache.QueryEntity
 import org.finos.vuu.core.module.simul.model.ChildOrder
 import org.finos.vuu.feature.ignite.utils.buildQueryEntity
@@ -13,4 +15,13 @@ object ChildOrderSchema {
     .build()
 
   val queryEntity: QueryEntity = buildQueryEntity(schema, classOf[Int], classOf[ChildOrder])
+
+  object toChildOrder {
+    private val mapper: JsonMapper with ClassTagExtensions = JsonMapper
+      .builder()
+      .addModule(DefaultScalaModule)
+      .build() :: ClassTagExtensions
+
+    def apply(l: List[_]): ChildOrder = mapper.convertValue(schema.toMap(l), classOf[ChildOrder])
+  }
 }

vuu/src/main/scala/org/finos/vuu/util/schema/ExternalEntitySchema.scala

@@ -6,8 +6,22 @@ import org.finos.vuu.util.schema.ExternalEntitySchemaBuilder.{InvalidIndexExcept
 import scala.collection.mutable.ListBuffer
 
 trait ExternalEntitySchema {
-  val fields: List[SchemaField]
-  val indexes: List[SchemaIndex] = List.empty
+  /**
+   * @return schema fields sorted by their index (SchemaField.index).
+   * */
+  def fields: List[SchemaField]
+
+  def indexes: List[SchemaIndex] = List.empty
+
+  /**
+   * @param values represents a list of values corresponding to the fields in the schema.
+   * @return a map from field names to the passed values matched by field.index that is
+   *         value at position 0 gets matched with the field x where x.index == 0.
+   *
+   * The method doesn't check for the types of passed values and would skip any fields
+   * that do not have a corresponding value e.g. when `values.length` < `fields.length`.
+   * */
+  def toMap(values: List[_]): Map[FieldName, Any] = fields.map(_.name).zip(values).toMap
 }
 
 private case class DefaultExternalEntitySchema private (override val fields: List[SchemaField],

vuu/src/test/scala/org/finos/vuu/util/schema/ExternalEntitySchemaTest.scala

@@ -3,7 +3,6 @@ package org.finos.vuu.util.schema
 import org.finos.vuu.util.schema.ExternalEntitySchemaBuilder.InvalidIndexException
 import org.scalatest.featurespec.AnyFeatureSpec
 import org.scalatest.matchers.should.Matchers
-import org.scalatest.prop.TableDrivenPropertyChecks._
 
 class ExternalEntitySchemaTest extends AnyFeatureSpec with Matchers {
   Feature("ExternalEntitySchemaBuilder") {
@@ -76,6 +75,28 @@ class ExternalEntitySchemaTest extends AnyFeatureSpec with Matchers {
       )
     }
   }
+
+  Feature("ExternalEntitySchema.toMap") {
+    val schema = ExternalEntitySchemaBuilder().withEntity(classOf[TestCaseClass]).build()
+
+    Scenario("Can convert list of values ordered according to the schema field index to a map of filedName->value") {
+      val m = schema.toMap(List("t-shirt", 3, 10.99))
+
+      m shouldEqual Map("name" -> "t-shirt", "size" -> 3, "value" -> 10.99)
+    }
+
+    Scenario("Can convert a list of correctly ordered values with some last missing to a map without the missing fields") {
+      val m = schema.toMap(List("t-shirt", 3))
+
+      m shouldEqual Map("name" -> "t-shirt", "size" -> 3)
+    }
+
+    Scenario("Can convert a list of correctly ordered values with extra values appended at the end to a map skipping any extra values") {
+      val m = schema.toMap(List("t-shirt", 3, 10.99, "extra-value-passed"))
+
+      m shouldEqual Map("name" -> "t-shirt", "size" -> 3, "value" -> 10.99)
+    }
+  }
 }
 
 private case class TestCaseClass(name: String, size: Int, value: Double)