XML (de)serialization
Circumflex ORM allows you to load graphs of associated records from XML files. This is very useful for loading test data and exchanging records between databases with associations preserving (in id-independent style).
Every Field capable of (de)serializing itself (from)into XML should extend the XmlSerializable trait. A record can be read from XML format if it contains only XmlSerializable fields.
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abstract class XmlSerializable[T, R <: Record[_, R]](
name: String, record: R, sqlType: String)
extends Field[T, R](name, record, sqlType) {
def fromString(str: String): Option[T]
def toString(value: Option[T]): String =
value.map(_.toString).getOrElse("")
}
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Deployment is a unit of work of XML import tool. It specifies the prefix for record classes resolution, the onExist behavior (keep, update or recreate) and whether record validation is needed before persisting. One deployment corresponds to one transaction, so each deployment is executed atomically.
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class Deployment(val id: String,
val prefix: String,
val onExist: Deployment.OnExistAction,
val validate: Boolean = true,
val entries: Seq[Node]) {
def process() {
try {
entries.foreach(e => processNode(e, Nil))
COMMIT()
} catch {
case e: Exception =>
ROLLBACK()
throw e
}
}
protected def processNode[R <: Record[Any, R]](
node: Node,
parentPath: Seq[Pair[Association[_, _, _], Record[_, _]]]): Record[Any, R] = {
val cl = pickClass(node)
var r = cl.newInstance.asInstanceOf[R]
var update = false
// Decide, whether a record should be processed, and how exactly.
if (node.attributes.next != null) {
val crit = prepareCriteria(r, node)
crit.unique() match {
case Some(rec: R) if (onExist == Deployment.Skip || node.child.size == 0) =>
return rec
case Some(rec: R) if (onExist == Deployment.Recreate) =>
crit.mkDelete().execute()
case Some(rec: R) if (onExist == Deployment.Update) =>
r = rec
update = true
case _ =>
}
}
// If we are still here, let's process the record further.
// In first place, we set provided parents
parentPath.foreach { p =>
if (r.relation.fields.contains(p._1.field))
r.relation.getField(r, p._1.field.asInstanceOf[Field[Any, R]]).set(p._2.PRIMARY_KEY.value)
}
var foreigns: Seq[Pair[Association[_, _, _], Node]] = Nil
// Secondly, we set fields provided via attributes
node.attributes.foreach(a => setRecordField(r, a.key, a.value.toString()))
// Next we process element body
node.child.foreach {
case n: Elem => try {
r.getClass.getMethod(n.label) match {
case m if (classOf[Field[_, _]].isAssignableFrom(m.getReturnType)) =>
setRecordField(r, n.label, n.child.mkString.trim)
case m if (classOf[Association[_, _, _]].isAssignableFrom(m.getReturnType)) =>
val a = m.invoke(r).asInstanceOf[Association[Any, R, R]]
val newPath = parentPath ++ List(a -> r)
val parent = if (n.child.size == 0) {
val newNode = Elem(null, a.parentRelation.recordClass.getSimpleName, n.attributes, n.scope)
Some(processNode(newNode, newPath))
} else n.child.find(_.isInstanceOf[Elem]).map(n => processNode(n, newPath))
r.relation.getField(r, a.field).set(parent.map(_.PRIMARY_KEY.value))
case m if (classOf[InverseAssociation[_, _, _, _]].isAssignableFrom(m.getReturnType)) =>
val a = m.invoke(r).asInstanceOf[InverseAssociation[Any, R, R, Any]].association
foreigns ++= n.child.filter(_.isInstanceOf[Elem]).map(n => (a -> n))
}
} catch {
case e: NoSuchMethodException =>
ORM_LOG.warn("Could not process '" + n.label + "' of " + r.getClass)
}
case _ =>
}
// Now the record is ready to be saved
if (update)
if (validate) r.UPDATE() else r.UPDATE_!()
else
if (validate) r.INSERT() else r.INSERT_!()
// Finally, we process the foreigners
foreigns.foreach(p =>
processNode(p._2, parentPath ++ List(p._1.asInstanceOf[Association[Any, R, R]] -> r)))
// And return our record
r
}
protected def pickClass(node: Node): Class[_] = {
var p = ""
if (prefix != "") p = prefix + "."
Class.forName(p + node.label, true, Thread.currentThread().getContextClassLoader)
}
protected def setRecordField[R <: Record[_, R]](r: R, k: String, v: String) = {
val m = r.getClass.getMethod(k)
if (classOf[Field[_, _]].isAssignableFrom(m.getReturnType)) { // only scalar fields are accepted
val field = m.invoke(r).asInstanceOf[Field[Any, R]]
val value = convertValue(field, v)
field.set(value)
}
}
protected def prepareCriteria[R <: Record[Any, R]](r: R, n: Node): Criteria[Any, R] = {
val crit = r.relation.AS("root").criteria
n.attributes.foreach(a => {
val k = a.key
val field = r.relation.getClass.getMethod(k).invoke(r).asInstanceOf[Field[Any, R]]
val v = convertValue(field, a.value.toString())
aliasStack.push("root")
crit.add(field EQ v)
})
crit
}
protected def convertValue(field: Field[Any, _], v: String): Option[Any] = field match {
case field: XmlSerializable[Any, _] => field.fromString(v)
case _ => Some(v)
}
override def toString = id match {
case "" => "deployment@" + hashCode
case _ => id
}
}
object Deployment {
trait OnExistAction
object Skip extends OnExistAction
object Update extends OnExistAction
object Recreate extends OnExistAction
def readOne(n: Node): Deployment = if (n.label == "deployment") {
val id = (n \ "@id").text
val prefix = (n \ "@prefix").text
val onExist = (n \ "@onExist").text match {
case "keep" | "ignore" | "skip" => Deployment.Skip
case "update" => Deployment.Update
case "recreate" | "delete" | "delete-create" | "overwrite" => Deployment.Recreate
case _ => Deployment.Skip
}
val validate = (n \ "@validate").text match {
case "false" | "f" | "no" | "off" => false
case _ => true
}
new Deployment(id, prefix, onExist, validate, n.child.filter(n => n.isInstanceOf[Elem]))
} else throw new ORMException("<deployment> expected, but <" + n.label + "> found.")
def readAll(n: Node): Seq[Deployment] = if (n.label == "deployments")
(n \ "deployment").map(n => readOne(n))
else throw new ORMException("<deployments> expected, but " + n.label + " found.")
}
class DeploymentHelper(f: File) {
def loadData() {
Deployment.readAll(XML.loadFile(f)).foreach(_.process())
}
}
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