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Diffstat (limited to 'src/library/scala/xml/persistent/CachedFileStorage.scala')
-rw-r--r-- | src/library/scala/xml/persistent/CachedFileStorage.scala | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/src/library/scala/xml/persistent/CachedFileStorage.scala b/src/library/scala/xml/persistent/CachedFileStorage.scala deleted file mode 100644 index 916a1a0cf7..0000000000 --- a/src/library/scala/xml/persistent/CachedFileStorage.scala +++ /dev/null @@ -1,125 +0,0 @@ -/* __ *\ -** ________ ___ / / ___ Scala API ** -** / __/ __// _ | / / / _ | (c) 2002-2013, LAMP/EPFL ** -** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** -** /____/\___/_/ |_/____/_/ | | ** -** |/ ** -\* */ - -package scala.xml -package persistent - -import java.io.{ File, FileOutputStream } -import java.nio.ByteBuffer -import java.nio.channels.Channels -import java.lang.Thread -import scala.util.logging.Logged -import scala.collection.Iterator - -/** Mutable storage of immutable xml trees. Everything is kept in memory, - * with a thread periodically checking for changes and writing to file. - * - * To ensure atomicity, two files are used, `filename1` and `'$'+filename1`. - * The implementation switches between the two, deleting the older one - * after a complete dump of the database has been written. - * - * @author Burak Emir - */ -abstract class CachedFileStorage(private val file1: File) extends Thread with Logged { - - private val file2 = new File(file1.getParent, file1.getName+"$") - - /** Either equals `file1` or `file2`, references the next file in which - * updates will be stored. - */ - private var theFile: File = null - - private def switch() = { theFile = if (theFile == file1) file2 else file1; } - - /** this storage modified since last modification check */ - protected var dirty = false - - /** period between modification checks, in milliseconds */ - protected val interval = 1000 - - /** finds and loads the storage file. subclasses should call this method - * prior to any other, but only once, to obtain the initial sequence of nodes. - */ - protected def initialNodes: Iterator[Node] = (file1.exists, file2.exists) match { - case (false,false) => - theFile = file1 - Iterator.empty - case (true, true ) if (file1.lastModified < file2.lastModified) => - theFile = file2 - load - case (true, _ ) => - theFile = file1 - load - case _ => - theFile = file2 - load - } - - /** returns an iterator over the nodes in this storage */ - def nodes: Iterator[Node] - - /** adds a node, setting this.dirty to true as a side effect */ - def += (e: Node): Unit - - /** removes a tree, setting this.dirty to true as a side effect */ - def -= (e: Node): Unit - - /* loads and parses XML from file */ - private def load: Iterator[Node] = { - import scala.io.Source - import scala.xml.parsing.ConstructingParser - log("[load]\nloading "+theFile) - val src = Source.fromFile(theFile) - log("parsing "+theFile) - val res = ConstructingParser.fromSource(src,false).document.docElem(0) - switch - log("[load done]") - res.child.iterator - } - - /** saves the XML to file */ - private def save() = if (this.dirty) { - log("[save]\ndeleting "+theFile) - theFile.delete() - log("creating new "+theFile) - theFile.createNewFile() - val fos = new FileOutputStream(theFile) - val c = fos.getChannel() - - // @todo: optimize - val storageNode = <nodes>{ nodes.toList }</nodes> - val w = Channels.newWriter(c, "utf-8") - XML.write(w, storageNode, "utf-8", true, null) - - log("writing to "+theFile) - - w.close - c.close - fos.close - dirty = false - switch - log("[save done]") - } - - /** Run method of the thread. remember to use `start()` to start a thread, - * not `run`. */ - override def run = { - log("[run]\nstarting storage thread, checking every "+interval+" ms") - while (true) { - Thread.sleep( this.interval ) - save - } - } - - /** Force writing of contents to the file, even if there has not been any - * update. */ - def flush() = { - this.dirty = true - save - } -} |