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2024-05-04 13:00:06 +02:00
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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)
}
}
}
}
}
}