Initial commit

src/main/kotlin/Main.kt

@@ -0,0 +1,5 @@
+package nl.astraeus
+
+fun main() {
+  println("Hello World!")
+}

src/main/kotlin/nl/astraeus/persistence/Datastore.kt

@@ -0,0 +1,229 @@
+package nl.astraeus.nl.astraeus.persistence
+
+import java.io.File
+import java.io.ObjectInputStream
+import java.io.ObjectOutputStream
+import java.io.Serializable
+import java.text.DecimalFormat
+import java.util.*
+import java.util.concurrent.ConcurrentHashMap
+import kotlin.reflect.KClass
+
+enum class ActionType {
+  STORE,
+  DELETE
+}
+
+class TypeData(
+  var nextId: Long = 1L,
+  val data: MutableMap<Any, Persistable> = ConcurrentHashMap(),
+) : Serializable
+
+class Action(
+  val type: ActionType,
+  val obj: Persistable
+) : Serializable
+
+class Datastore(
+  private val directory: File,
+  indexes: Array<PersistableIndex> = arrayOf(),
+) {
+  private val fileManager = FileManager(directory)
+  private val transactionFormatter = DecimalFormat("#")
+  private var nextTransactionNumber = 1L
+  private val data: MutableMap<Class<*>, TypeData> = ConcurrentHashMap()
+  private val indexes: MutableMap<Class<*>, MutableMap<String, PersistableIndex>> = ConcurrentHashMap()
+
+  init {
+    if (!directory.exists()) {
+      directory.mkdirs()
+    }
+
+    for (index in indexes) {
+      this.indexes.getOrPut(index.cls) {
+        ConcurrentHashMap()
+      }[index.name] = index
+    }
+
+    loadTransactions()
+  }
+
+  private fun loadTransactions() {
+    synchronized(this) {
+      val snapshots: Array<File>? = directory.listFiles { _, name -> name.startsWith("transaction-") && name.endsWith(".snp") }
+      val files: Array<File>? = directory.listFiles { _, name -> name.startsWith("transaction-") && name.endsWith(".trn") }
+
+      var lastSnapshot: Long? = null
+      var lastSnapshotFile: File? = null
+
+      snapshots?.let {
+        it.forEach {
+          val trnx = getTrnx(it)
+          if (lastSnapshot == null || trnx > (lastSnapshot ?: 0L)) {
+            lastSnapshot = trnx
+            lastSnapshotFile = it
+          }
+        }
+      }
+
+      val lastSnapshotFile2 = fileManager.findLastSnapshot()
+
+      if (lastSnapshotFile != null) {
+        ObjectInputStream(lastSnapshotFile?.inputStream()).use { ois ->
+          readSnapshot(ois)
+        }
+      }
+
+      val trns = fileManager.findTransactionsAfter(lastSnapshot ?: 0L)
+
+      files?.also { snaphotFiles ->
+        Arrays.sort(snaphotFiles) { o1, o2 -> if (getTrnx(o1) > getTrnx(o2)) 1 else -1}
+
+        snaphotFiles.forEach { file ->
+          if (getTrnx(file) > (lastSnapshot ?: 0L)) {
+            ObjectInputStream(file.inputStream()).use { ois ->
+              val transactionNumber = ois.readLong()
+              nextTransactionNumber = transactionNumber + 1
+              val actions = ois.readObject() as MutableList<Action>
+              execute(actions)
+            }
+          }
+        }
+      }
+    }
+  }
+
+  private fun getTrnx(file: File): Long {
+    return file.name.substringAfterLast('/').substringAfter("transaction-").substringBefore(".").toLong()
+  }
+
+  fun execute(actions: MutableList<Action>) {
+    synchronized(this) {
+      for (action in actions) {
+        val typeData = data.getOrPut(action.obj::class.java) {
+          TypeData()
+        }
+
+        when (action.type) {
+          ActionType.STORE -> {
+            if (action.obj.id == 0L) {
+              action.obj.id = typeData.nextId++
+            }
+            typeData.data[action.obj.id] = action.obj
+
+            for (index in indexes[action.obj::class.java]?.values ?: listOf()) {
+              index.add(action.obj as Persistable)
+            }
+          }
+
+          ActionType.DELETE -> {
+            typeData.data.remove(action.obj.id)
+
+            for (index in indexes[action.obj::class.java]?.values ?: listOf()) {
+              index.remove(action.obj)
+            }
+          }
+        }
+      }
+    }
+  }
+
+  fun <T : Persistable> find(clazz: KClass<T>, id: Long): T? {
+    val typeData = data.getOrPut(clazz.java) {
+      TypeData()
+    }
+
+    val p: Persistable? = typeData.data[id]
+
+    return (p?.copy() as T?)
+  }
+
+  fun <T : Persistable> search(
+    clazz: KClass<T>,
+    search: (T) -> Boolean
+  ): List<T> {
+    val typeData = data.getOrPut(clazz.java) {
+      TypeData()
+    }
+
+    return typeData.data.values
+      .filter { search(it as T) }
+      .map { o -> o.copy() as T }
+  }
+
+  fun findIndex(
+    kClass: KClass<*>,
+    indexName: String
+  ): PersistableIndex? {
+    return indexes[kClass.java]?.get(indexName)
+  }
+
+  fun storeActions(actions: MutableList<Action>) {
+    if (actions.isNotEmpty()) {
+      synchronized(this) {
+        val number = transactionFormatter.format(nextTransactionNumber)
+        val file = File(directory, "transaction-$number.trn")
+        ObjectOutputStream(file.outputStream()).use { oos ->
+          oos.writeLong(nextTransactionNumber++)
+          oos.writeObject(actions)
+        }
+      }
+    }
+  }
+
+  fun snapshot() {
+    synchronized(this) {
+      val number = transactionFormatter.format(nextTransactionNumber)
+      val file = File(directory, "transaction-$number.snp")
+      ObjectOutputStream(file.outputStream()).use { oos ->
+        oos.writeLong(nextTransactionNumber++)
+        oos.writeObject(data)
+        oos.writeInt(indexes.size)
+        for ((cls, index) in indexes) {
+          oos.writeObject(cls)
+          oos.writeInt(index.size)
+          for ((name, idx) in index) {
+            oos.writeObject(name)
+            oos.writeObject(idx.index)
+          }
+        }
+      }
+    }
+  }
+
+  private fun readSnapshot(ois: ObjectInputStream) {
+    nextTransactionNumber = ois.readLong() + 1
+    data.clear()
+    data.putAll(ois.readObject() as MutableMap<Class<*>, TypeData>)
+
+    val foundIndexes = mutableMapOf<Class<*>, MutableList<String>>()
+    val numberOfClassesWithIndex = ois.readInt()
+    for (i in 0 until numberOfClassesWithIndex) {
+      val cls = ois.readObject() as Class<*>
+      val numberOfIndexesForClass = ois.readInt()
+      for (indexForClass in 0 until numberOfIndexesForClass) {
+        val name = ois.readObject() as String
+        val idx = ois.readObject() as MutableMap<Serializable, MutableSet<Long>>
+        foundIndexes.getOrPut(cls) { mutableListOf() }.add(name)
+
+        val index = indexes[cls]
+        if (index != null) {
+          index[name]?.index?.putAll(idx)
+        } // else ignore, index is removed
+      }
+    }
+
+    // any (new) index not serialized needs to be build now
+    for ((cls, indexes) in indexes) {
+      for ((name, index) in indexes) {
+        if (!foundIndexes.getOrDefault(cls, mutableListOf()).contains(name)) {
+          index.index.clear()
+          for (obj in data.getOrDefault(cls, TypeData()).data.values) {
+            index.add(obj)
+          }
+        }
+      }
+    }
+  }
+
+}

src/main/kotlin/nl/astraeus/persistence/Indexing.kt

@@ -0,0 +1,37 @@
+package nl.astraeus.nl.astraeus.persistence
+
+import java.io.Serializable
+import kotlin.reflect.KClass
+
+typealias PersistableIndex = Index<out Persistable>
+
+class Index<T : Persistable>(
+  kcls: KClass<T>,
+  val name: String,
+  val value: (Persistable) -> Serializable?,
+) : Serializable {
+  val cls: Class<T> = kcls.java
+  val index = mutableMapOf<Serializable, MutableSet<Long>>()
+
+  fun add(obj: Persistable) {
+    val key = value(obj)
+
+    key?.also {
+      index.getOrPut(it) { mutableSetOf() }.add(obj.id)
+    }
+  }
+
+  fun remove(obj: Persistable) {
+    val key = value(obj)
+
+    index[key]?.remove(obj.id)
+  }
+
+  fun find(key: Any): List<T> {
+    return index[key]?.mapNotNull { currentTransaction()?.find(cls.kotlin, it) } ?: emptyList()
+  }
+
+  fun matches(obj: Persistable, value: Any): Boolean {
+    return value(obj) == value
+  }
+}

src/main/kotlin/nl/astraeus/persistence/Persistable.kt

@@ -0,0 +1,25 @@
+package nl.astraeus.nl.astraeus.persistence
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.ObjectInputStream
+import java.io.ObjectOutputStream
+import java.io.Serializable
+
+interface Persistable : Serializable, Cloneable {
+  var id: Long
+  var version: Long
+
+  fun copy(): Persistable {
+    ByteArrayOutputStream().use { baos ->
+      ObjectOutputStream(baos).use { oos ->
+        oos.writeObject(this)
+      }
+      ByteArrayInputStream(baos.toByteArray()).use { bais ->
+        ObjectInputStream(bais).use { ois ->
+          return ois.readObject() as Persistable
+        }
+      }
+    }
+  }
+}

src/main/kotlin/nl/astraeus/persistence/Persistent.kt

@@ -0,0 +1,38 @@
+package nl.astraeus.nl.astraeus.persistence
+
+import java.io.File
+
+private val transactions: ThreadLocal<Transaction> = ThreadLocal<Transaction>()
+
+fun currentTransaction(): Transaction? {
+  return transactions.get()
+}
+
+class Persistent(
+  directory: File,
+  indexes: Array<PersistableIndex> = arrayOf(),
+) {
+  val datastore: Datastore = Datastore(directory, indexes)
+
+  fun transaction(block: Transaction.() -> Unit) {
+    var cleanup = false
+    if (transactions.get() == null) {
+      transactions.set(Transaction(this))
+      cleanup = true
+    }
+
+    try {
+      block(transactions.get())
+
+      transactions.get().commit()
+    } finally {
+      if (cleanup) {
+        transactions.remove()
+      }
+    }
+  }
+
+  fun snapshot() {
+    datastore.snapshot()
+  }
+}

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

@@ -0,0 +1,133 @@
+package nl.astraeus.nl.astraeus.persistence
+
+import java.io.Serializable
+import kotlin.reflect.KProperty
+
+class Reference<S : Persistable, H : Persistable>(
+  val cls: Class<S>,
+) : Serializable {
+  companion object {
+    private const val serialVersionUID: Long = 1L
+  }
+
+  var id: Long = 0
+
+  operator fun getValue(thisRef: H, property: KProperty<*>): S {
+    return currentTransaction()?.find(cls.kotlin, id) ?: throw IllegalStateException("Reference not found")
+  }
+
+  operator fun setValue(thisRef: H, property: KProperty<*>, value: S) {
+    id = value.id
+    currentTransaction()?.store(value)
+  }
+
+}
+
+class ListReference<S : Persistable, H : Persistable>(
+  val cls: Class<S>,
+) : Serializable {
+  companion object {
+    private const val serialVersionUID: Long = 1L
+  }
+
+  var ids: ReferenceList<S> = ReferenceList(cls)
+
+  operator fun getValue(thisRef: H, property: KProperty<*>): ReferenceList<S> {
+    return ids
+  }
+
+  operator fun setValue(thisRef: H, property: KProperty<*>, value: List<S>) {
+    this.ids.clear()
+    this.ids.addAll(value)
+  }
+}
+
+class ReferenceList<T : Persistable>(
+  val cls: Class<T>,
+) : MutableList<T> {
+  val ids = ArrayList<Long>()
+
+  private fun checkElementIsPersisted(element: T) {
+    if (currentTransaction()?.find(cls.kotlin, element.id) == null) {
+      currentTransaction()?.store(element)
+    }
+  }
+
+  override val size: Int = ids.size
+  override fun clear() = ids.clear()
+
+  override fun addAll(elements: Collection<T>): Boolean {
+    TODO("Not yet implemented")
+  }
+
+  override fun addAll(index: Int, elements: Collection<T>): Boolean {
+    TODO("Not yet implemented")
+  }
+
+  override fun add(index: Int, element: T) {
+    ids.add(index, element.id)
+  }
+
+  override fun add(element: T): Boolean {
+    return ids.add(element.id)
+  }
+
+  override fun get(index: Int): T = currentTransaction()?.find(cls.kotlin, ids[index]) ?: throw IllegalStateException("Reference not found")
+
+  override fun isEmpty(): Boolean = ids.isEmpty()
+
+  override fun iterator(): MutableIterator<T> {
+    TODO("Not yet implemented")
+  }
+
+  override fun listIterator(): MutableListIterator<T> {
+    TODO("Not yet implemented")
+  }
+
+  override fun listIterator(index: Int): MutableListIterator<T> {
+    TODO("Not yet implemented")
+  }
+
+  override fun removeAt(index: Int): T {
+    val id = ids.removeAt(index)
+
+    return currentTransaction()?.find(cls.kotlin, id) ?: throw IllegalStateException("Reference not found")
+  }
+
+  override fun set(index: Int, element: T): T {
+    TODO("Not yet implemented")
+  }
+
+  override fun retainAll(elements: Collection<T>): Boolean {
+    TODO("Not yet implemented")
+  }
+
+  override fun removeAll(elements: Collection<T>): Boolean {
+    TODO("Not yet implemented")
+  }
+
+  override fun remove(element: T): Boolean {
+    TODO("Not yet implemented")
+  }
+
+  override fun subList(fromIndex: Int, toIndex: Int): MutableList<T> {
+    TODO("Not yet implemented")
+  }
+
+  override fun lastIndexOf(element: T): Int {
+    TODO("Not yet implemented")
+  }
+
+  override fun indexOf(element: T): Int {
+    TODO("Not yet implemented")
+  }
+
+  override fun containsAll(elements: Collection<T>): Boolean {
+    TODO("Not yet implemented")
+  }
+
+  override fun contains(element: T): Boolean {
+    TODO("Not yet implemented")
+  }
+
+}

src/main/kotlin/nl/astraeus/persistence/Transaction.kt

@@ -0,0 +1,100 @@
+package nl.astraeus.nl.astraeus.persistence
+
+import java.io.Serializable
+import kotlin.reflect.KClass
+
+class Transaction(
+  val persistent: Persistent,
+) : Serializable {
+  private val actions = mutableListOf<Action>()
+
+  fun store(obj: Persistable) {
+    actions.add(Action(ActionType.STORE, obj))
+  }
+
+  fun delete(obj: Persistable) {
+    actions.add(Action(ActionType.DELETE, obj))
+  }
+
+  fun <T : Persistable> find(clazz: KClass<T>, id: Long): T? {
+    var result: T? = persistent.datastore.find(clazz, id)
+
+    for (action in actions) {
+      if (action.obj::class == clazz && action.obj.id == id) {
+        result = when {
+          action.type == ActionType.DELETE -> {
+            null
+          }
+
+          action.type == ActionType.STORE -> {
+            action.obj as? T
+          }
+
+          else -> {
+            result
+          }
+        }
+      }
+    }
+
+    return result
+  }
+
+  fun <T : Persistable> search(clazz: KClass<T>, search: (T) -> Boolean): List<T> {
+    val fromDatastore: List<T> = persistent.datastore.search(clazz, search)
+    val result = mutableListOf<T>()
+    result.addAll(fromDatastore)
+
+    for (obj in result) {
+      for (action in actions) {
+        if (action.obj.id == obj.id) {
+          if (action.type == ActionType.DELETE) {
+            result.remove(obj)
+          } else if (action.type == ActionType.STORE) {
+            result.remove(obj)
+            result.add(action.obj as T)
+          }
+        }
+      }
+    }
+
+    return result
+  }
+
+  fun commit() {
+    persistent.datastore.storeActions(actions)
+    persistent.datastore.execute(actions)
+    actions.clear()
+  }
+
+  fun <T : Persistable> findByIndex(
+    kClass: KClass<T>,
+    indexName: String,
+    search: Any
+  ): List<T> {
+    val result = mutableListOf<T>()
+    val index = persistent.datastore.findIndex(kClass, indexName) ?: throw IllegalArgumentException("Index not found")
+
+    index.find(search).forEach { id ->
+      result.add(id as T)
+    }
+
+    for (action in actions) {
+      if (action.obj::class == kClass) {
+        if (action.type == ActionType.DELETE) {
+          if (index.matches(action.obj, search)) {
+            result.remove(action.obj as T)
+          }
+        } else if (action.type == ActionType.STORE) {
+          if (index.matches(action.obj, search)) {
+            result.remove(action.obj)
+            result.add(action.obj as T)
+          }
+        }
+      }
+    }
+
+    return result
+  }
+
+}

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

@@ -0,0 +1,152 @@
+package nl.astraeus.persistence
+
+import nl.astraeus.nl.astraeus.persistence.Index
+import nl.astraeus.nl.astraeus.persistence.Persistable
+import nl.astraeus.nl.astraeus.persistence.Persistent
+import nl.astraeus.nl.astraeus.persistence.Reference
+import java.io.File
+import kotlin.test.Test
+
+class TestPersistence {
+
+  class Company(
+    override var id: Long = 0,
+    override var version: Long = 0,
+    val name: String
+  ) : Persistable, Cloneable {
+    //var persons: MutableList<Person> by ListReference<Person, Company>(Person::class.java)
+
+    companion object {
+      private const val serialVersionUID: Long = 1L
+    }
+  }
+
+  class Person(
+    override var id: Long = 0,
+    override var version: Long = 0,
+    val name: String,
+    val age: Int,
+  ) : Persistable, Cloneable {
+    var company: Company by Reference<Company, Person>(Company::class.java)
+
+    companion object {
+      private const val serialVersionUID: Long = 1L
+    }
+  }
+
+  @Test
+  fun testPersistence() {
+    println("Test persistence")
+
+    val pst = Persistent(
+      directory = File("data"),
+      arrayOf(
+        Index(Person::class, "name") { p -> (p as? Person)?.name ?: "" },
+        Index(Person::class, "age") { p -> (p as? Person)?.age ?: -1 },
+        Index(Person::class, "ageGt20") { p -> ((p as? Person)?.age ?: 0) > 20 },
+        Index(Person::class, "ageGt23") { p -> ((p as? Person)?.age ?: 0) > 23 },
+        Index(Person::class, "ageOnlyGt20") { p ->
+          if (((p as? Person)?.age ?: 0) > 20) {
+            true
+          } else {
+            null
+          }
+        },
+        Index(Company::class, "name") { p -> (p as? Company)?.name ?: "" },
+      )
+    )
+
+    pst.transaction {
+      val person = find(Person::class, 1L) ?: Person(
+        id = 1L,
+        name = "John Doe",
+        age = 25
+      )
+
+      val company = find(Company::class, 1L) ?: Company(
+        id = 1L,
+        name = "ACME"
+      )
+
+      person.company = company
+      //company.persons.add(person)
+
+      store(person)
+      store(Person(
+        id = 2L,
+        name = "John Doe",
+        age = 23
+      ))
+      store(Person(
+        id = 3L,
+        name = "John Doe",
+        age = 18
+      ))
+
+      findByIndex(Person::class, "name", "John Doe").forEach { p ->
+        println("Found person by name: ${p.name} - ${p.age}")
+      }
+
+      findByIndex(Person::class, "age", 23).forEach { p ->
+        println("Found person by age: ${p.name} - ${p.age}")
+      }
+
+      findByIndex(Person::class, "ageGt20", true).forEach { p ->
+        println("Found person by age > 20: ${p.name} - ${p.age}")
+      }
+
+      findByIndex(Person::class, "ageGt23", true).forEach { p ->
+        println("Found person by age > 23: ${p.name} - ${p.age}")
+      }
+
+      findByIndex(Person::class, "ageGt20", false).forEach { p ->
+        println("Found person by age <= 20: ${p.name} - ${p.age}")
+      }
+
+      val p2 = find(Person::class, 1L)
+
+      assert(p2 != null)
+
+      val c2 = find(Company::class, 1L)
+
+      assert(c2 != null)
+    }
+
+    pst.transaction {
+      val person = find(Person::class, 1L)
+
+      delete(person!!)
+
+      val p2 = find(Person::class, 1L)
+
+      assert(p2 == null)
+    }
+
+    pst.transaction {
+      val persons = search(Person::class) { p -> p.name == "John Doe" }
+
+      if (persons.isNotEmpty()) {
+        delete(persons[0])
+      }
+    }
+
+    pst.snapshot()
+
+    pst.transaction {
+      store(
+        Person(
+          id = 10L,
+          name = "Pipo",
+          age = 23
+        )
+      )
+      store(
+        Person(
+          id = 11L,
+          name = "Clown",
+          age = 18
+        )
+      )
+    }
+  }
+}