nullable, non-nullable reference

src/main/kotlin/nl/astraeus/persistence/reference/Reference.kt

@@ -6,10 +6,33 @@ import java.io.Serializable
 import kotlin.reflect.KProperty
 
 inline fun <reified T : Persistable> reference(
-) = Reference(T::class.java)
+  initialValue:T
+) = Reference(T::class.java, initialValue)
 
+inline fun <reified T : Persistable> nullableReference(
+) = NullableReference(T::class.java)
 
 class Reference<S : Persistable>(
+  val cls: Class<S>,
+  initialValue: S
+) : Serializable {
+  var id: Long = initialValue.id
+
+  operator fun getValue(thisRef: Persistable, property: KProperty<*>): S {
+    return currentTransaction()?.find(cls.kotlin, id) ?: throw IllegalStateException("Reference not found")
+  }
+
+  operator fun setValue(thisRef: Persistable, property: KProperty<*>, value: S) {
+    currentTransaction()?.store(value)
+    id = value.id
+  }
+
+  companion object {
+    private const val serialVersionUID: Long = 1L
+  }
+}
+
+class NullableReference<S : Persistable>(
   val cls: Class<S>
 ) : Serializable {
   var id: Long? = null

src/test/kotlin/nl/astraeus/persistence/TestReferences.kt

@@ -5,6 +5,7 @@ import nl.astraeus.nl.astraeus.persistence.Persistent
 import nl.astraeus.nl.astraeus.persistence.TransactionLog
 import nl.astraeus.nl.astraeus.persistence.reference.reference
 import nl.astraeus.nl.astraeus.persistence.reference.referenceCollection
+import org.junit.jupiter.api.assertThrows
 import java.io.File
 import kotlin.test.Test
 
@@ -31,15 +32,16 @@ class TestReferences {
     override var version: Long = 0,
     val name: String,
     val age: Int,
+    company: Company
   ) : Persistable, Cloneable {
-    var company: Company? by reference()
+    var company: Company by reference(company)
 
     companion object {
       private const val serialVersionUID: Long = 1L
     }
 
     override fun toString(): String {
-      return "Person(id=$id, version=$version, name='$name', age=$age, company=$company)"
+      return "Person(id=$id, version=$version, name='$name', age=$age)"
     }
   }
 
@@ -57,31 +59,35 @@ class TestReferences {
     )
 
     pst.transaction {
-      val company = find(Company::class, 1L) ?: Company(
+      val company = Company(
         id = 1L,
         name = "ACME"
       )
 
-      if (company.persons.isEmpty()) {
-        val person = Person(
-          id = 0L,
-          name = "John Doe",
-          age = 25
-        )
-        person.company = company
-        store(person)
-        company.persons.add(person)
-      } else {
-        for (person in company.persons) {
-          println("Found stored Person: $person")
-        }
-      }
+      val person = Person(
+        id = 0L,
+        name = "John Doe",
+        age = 25,
+        company = company
+      )
+      store(person)
+
+      company.persons.add(person)
 
       store(company)
 
-      for (person in company.persons) {
-        println("Person: $person")
+      for (p in company.persons) {
+        println("Person: $p")
       }
+
+      delete(company)
+
+      // company is gone, can't get it through person anymore
+      assertThrows<IllegalStateException> {
+        println("Company in person: ${person.company}")
+      }
+
+      delete(person)
     }
   }