Add Reference/Collections

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

@@ -0,0 +1,82 @@
+package nl.astraeus.nl.astraeus.persistence.reference
+
+import nl.astraeus.nl.astraeus.persistence.Persistable
+import nl.astraeus.nl.astraeus.persistence.currentTransaction
+import java.io.Serializable
+
+inline fun <reified T : Persistable> referenceCollection(
+  ids: MutableCollection<Long> = mutableListOf()
+) = ReferenceCollection(T::class.java, ids)
+
+open class ReferenceCollection<T : Persistable>(
+  val cls: Class<T>,
+  val ids: MutableCollection<Long> = mutableListOf()
+) : MutableCollection<T>, Serializable {
+
+  protected fun checkElementIsPersisted(element: T) {
+    if (currentTransaction()?.find(cls.kotlin, element.id) == null) {
+      currentTransaction()?.store(element)
+    }
+  }
+
+  override val size: Int
+    get() {
+      return ids.size
+    }
+
+  override fun clear() {
+    ids.clear()
+  }
+
+  override fun isEmpty(): Boolean = ids.isEmpty()
+
+  override fun iterator(): MutableIterator<T> {
+    return object : MutableIterator<T> {
+      private var idsIterator = ids.iterator()
+
+      override fun hasNext(): Boolean = idsIterator.hasNext()
+
+      override fun next(): T = idsIterator.next().let {
+        currentTransaction()?.find(cls.kotlin, it)
+      } ?: throw IllegalStateException("Reference not found")
+
+      override fun remove() = idsIterator.remove()
+    }
+  }
+
+  override fun retainAll(elements: Collection<T>): Boolean {
+    return ids.retainAll(elements.map { it.id }.toSet())
+  }
+
+  override fun removeAll(elements: Collection<T>): Boolean {
+    return ids.removeAll(elements.map { it.id }.toSet())
+  }
+
+  override fun remove(element: T): Boolean {
+    return ids.remove(element.id)
+  }
+
+  override fun containsAll(elements: Collection<T>): Boolean {
+    return ids.containsAll(elements.map { it.id })
+  }
+
+  override fun contains(element: T): Boolean {
+    return ids.contains(element.id)
+  }
+
+  override fun addAll(elements: Collection<T>): Boolean {
+    for (element in elements) {
+      checkElementIsPersisted(element)
+    }
+    return ids.addAll(elements.map { it.id })
+  }
+
+  override fun add(element: T): Boolean {
+    checkElementIsPersisted(element)
+    return ids.add(element.id)
+  }
+
+  companion object {
+    private const val serialVersionUID: Long = 1L
+  }
+}