li/cil/oc/server/network/Network.scala - minecraft/opencomputers - Rivoreo Source Code Repositories

 package li.cil.oc.server.network

 import _root_.net.minecraft.block.Block
 import _root_.net.minecraft.tileentity.TileEntity
 import _root_.net.minecraft.world.{IBlockAccess, World}
 import _root_.net.minecraftforge.common.ForgeDirection
 import _root_.net.minecraftforge.event.ForgeSubscribe
 import _root_.net.minecraftforge.event.world.ChunkEvent
 import java.util.logging.Level
 import li.cil.oc.api.network.Visibility
 import li.cil.oc.api.{network => net}
 import li.cil.oc.server.network.Network.Node
 import li.cil.oc.{api, OpenComputers}
 import scala.beans.BeanProperty
 import scala.collection.JavaConverters._
 import scala.collection.mutable
 import scala.collection.mutable.ArrayBuffer

 /**
  * Network implementation for component networks.
  *
  * This network interconnects components in a geometry-agnostic fashion. It
  * builds an internal graph of network nodes and the connections between them,
  * and takes care of merges when adding connections, as well as net splits on
  * node removal.
  *
  * It keeps the list of nodes as a lookup table for fast id->node resolving.
  * Note that it is possible for multiple nodes to have the same ID, though.
  */
 class Network private(private val nodeMap: mutable.Map[Int, ArrayBuffer[Network.Node]]) extends api.Network {
   def this(node: net.Node) = {
     this(mutable.Map({
       if (node.address < 1)
         node.address = 1
       node.address -> ArrayBuffer(new Network.Node(node))
     }))
     send(new Network.ConnectMessage(node), List(node))
   }

   nodes.foreach(_.network = Some(this))

   def connect(nodeA: net.Node, nodeB: net.Node) = {
     val containsA = nodeMap.get(nodeA.address).exists(_.exists(_.data == nodeA))
     val containsB = nodeMap.get(nodeB.address).exists(_.exists(_.data == nodeB))
     if (!containsA && !containsB) throw new IllegalArgumentException(
       "At least one of the nodes must already be in this network.")

     def oldNodeA = nodeMap(nodeA.address).find(_.data == nodeA).get
     def oldNodeB = nodeMap(nodeB.address).find(_.data == nodeB).get
     if (containsA && containsB) {
       // Both nodes already exist in the network but there is a new connection.
       // This can happen if a new node sequentially connects to multiple nodes
       // in an existing network, e.g. in a setup like so:
       // O O   Where O is an old node, and N is the new Node. It would connect
       // O N   to the node above and left to it (in no particular order).
       if (!oldNodeA.edges.exists(_.isBetween(oldNodeA, oldNodeB))) {
         assert(!oldNodeB.edges.exists(_.isBetween(oldNodeA, oldNodeB)))
         Network.Edge(oldNodeA, oldNodeB)
         true
       }
       // That connection already exists.
       else false
     }
     // New node for this network, order the nodes and add the new one.
     else if (containsA) add(oldNodeA, nodeB)
     else add(oldNodeB, nodeA)
   }

   private def add(oldNode: Network.Node, addedNode: net.Node) = {
     // Check if the other node is new or if we have to merge networks.
     val (newNode, sendQueue) = if (addedNode.network.isEmpty) {
       val newNode = new Network.Node(addedNode)
       if (nodeMap.contains(addedNode.address) || addedNode.address < 1)
         addedNode.address = findId()
       // Store everything with an invalid address in slot zero.
       val address = addedNode.address match {
         case a if a > 0 => a
         case _ => 0
       }
       // Create the message queue. The address check is purely for performance,
       // since we can skip all that if the node is non-valid.
       val sendQueue = mutable.Buffer.empty[(Network.Message, Iterable[net.Node])]
       if (address > 0 && addedNode.visibility != Visibility.None) {
         sendQueue += ((new Network.ConnectMessage(addedNode), List(addedNode) ++ nodes))
         nodes.foreach(node => sendQueue += ((new Network.ConnectMessage(node), List(addedNode))))
       }
       nodeMap.getOrElseUpdate(address, new ArrayBuffer[Network.Node]) += newNode
       addedNode.network = Some(this)
       (newNode, sendQueue)
     }
     else {
       // Queue any messages to avoid side effects from receivers.
       val sendQueue = mutable.Buffer.empty[(Network.Message, Iterable[net.Node])]
       val thisNodes = nodes.toBuffer
       val otherNetwork = addedNode.network.get.asInstanceOf[Network]
       val otherNodes = otherNetwork.nodes.toBuffer
       otherNodes.foreach(node => sendQueue += ((Network.ConnectMessage(node), thisNodes)))
       thisNodes.foreach(node => sendQueue += ((Network.ConnectMessage(node), otherNodes)))

       // Change addresses for conflicting nodes in other network. We can queue
       // these messages because we're storing references to the nodes, so they
       // will send the change notification to the right node even if that node
       // also changes its address.
       val reserved = mutable.Set(otherNetwork.nodeMap.keySet.toSeq: _*)
       otherNodes.filter(node => nodeMap.contains(node.address)).foreach(node => {
         val oldAddress = node.address
         node.address = findId(reserved)
         if (node.address != oldAddress) {
           reserved += node.address
           // Prepend to notify old nodes of address changes first.
           sendQueue.+=:((Network.ReconnectMessage(node, oldAddress), otherNodes))
         }
       })

       // Add nodes from other network into this network, including invalid nodes.
       otherNetwork.nodeMap.values.flatten.foreach(node => {
         nodeMap.getOrElseUpdate(node.data.address, new ArrayBuffer[Network.Node]) += node
         node.data.network = Some(this)
       })

       // Return the node object of the newly connected node for the next step.
       (nodeMap(addedNode.address).find(_.data == addedNode).get, sendQueue)
     }

     // Add the connection between the two nodes.
     Network.Edge(oldNode, newNode)

     // Send all generated messages.
     for ((message, nodes) <- sendQueue) send(message, nodes)

     true
   }

   def reconnect(node: net.Node, address: Int): Boolean = {
     if (!nodeMap.get(node.address).exists(_.exists(_.data == node))) throw new IllegalArgumentException(
       "The node must already be in this network.")

     val oldAddress = node.address
     if (address == oldAddress) false
     else {
       val otherMessage = if (address < 1) {
         node.address = 0
         None
       }
       else {
         // Check if there's a simple collision, if so resolve it.
         nodeMap.get(address) match {
           case None =>
             // No collision.
             node.address = address
             None
           case Some(otherList) =>
             if (otherList.size > 1)
               return false // Already multiple nodes with that address...
             else {
               // Simple collision.
               val other = otherList.head
               otherList -= other

               other.data.address = findId()
               nodeMap.getOrElseUpdate(other.data.address, new mutable.ArrayBuffer[Node]) += other
               Some((Network.ReconnectMessage(other.data, address), nodes))
             }
         }
       }

       val oldList = nodeMap(oldAddress)
       val innerNode = oldList.remove(oldList.indexWhere(_.data == node))
       if (oldList.isEmpty)
         nodeMap -= oldAddress
       nodeMap.getOrElseUpdate(node.address, new mutable.ArrayBuffer[Node]) += innerNode

       otherMessage.foreach {
         case (message, targets) => send(message, targets)
       }
       send(Network.ReconnectMessage(node, oldAddress), nodes)

       true
     }
   }

   def disconnect(nodeA: net.Node, nodeB: net.Node) = {
     val containsA = nodeMap.get(nodeA.address).exists(_.exists(_.data == nodeA))
     val containsB = nodeMap.get(nodeB.address).exists(_.exists(_.data == nodeB))
     if (!containsA || !containsB) throw new IllegalArgumentException(
       "Both of the nodes must be in this network.")

     def oldNodeA = nodeMap(nodeA.address).find(_.data == nodeA).get
     def oldNodeB = nodeMap(nodeB.address).find(_.data == nodeB).get
     oldNodeA.edges.find(_.isBetween(oldNodeA, oldNodeB)) match {
       case None => false // That connection doesn't exists.
       case Some(edge) => {
         handleSplit(edge.remove())
         true
       }
     }
   }

   def remove(node: net.Node) = nodeMap.get(node.address) match {
     case None => false
     case Some(list) => list.find(_.data == node) match {
       case None => false
       case Some(entry) => {
         node.network = None

         // Removing a node may result in a net split, leaving us with multiple
         // networks. The remove function returns all resulting networks, one
         // of which we'll re-use for this network. For all additional ones we
         // create new network instances.
         handleSplit(entry.remove(), nodes => {
           nodes.foreach(n => send(new Network.DisconnectMessage(n), List(node)))
           send(new Network.DisconnectMessage(node), nodes)
         })
         send(new Network.DisconnectMessage(node), List(node))
         true
       }
     }
   }

   private def handleSplit(subGraphs: Seq[mutable.Map[Int, ArrayBuffer[Network.Node]]],
                           messageCallback: Iterable[net.Node] => Unit = _ => {}) = {
     // Sending the removal messages can have side effects, so we'll keep a
     // copy of the original list of nodes in each sub network.
     val subNodes = subGraphs.map(_.values.flatten.map(_.data).toBuffer).toBuffer

     // We re-use this network by assigning the first sub graph to it. For
     // all additional sub graphs (if any) we'll have to create new ones.
     nodeMap.clear()
     // Empty for the last node removed from a network.
     if (!subGraphs.isEmpty) {
       nodeMap ++= subGraphs.head
       subGraphs.tail.foreach(new Network(_))
     }

     // Send removal messages. First, to the removed node itself (for its
     // onDisconnect handler), then one for the removed node to all sub
     // networks, for each node in the sub networks back to the removed node
     // and if there was a net split (we have multiple networks) also for
     // each node now longer belonging to one of the resulting sub networks.
     for (indexA <- 0 until subNodes.length) {
       val nodesA = subNodes(indexA)
       for (indexB <- (indexA + 1) until subNodes.length) {
         val nodesB = subNodes(indexB)
         nodesA.foreach(nodeA => send(new Network.DisconnectMessage(nodeA), nodesB))
         nodesB.foreach(nodeB => send(new Network.DisconnectMessage(nodeB), nodesA))
       }
       messageCallback(nodesA)
     }
   }

   def node(address: Int) = nodeMap.get(address) match {
     case Some(list) if address > 0 => list.map(_.data).filter(_.visibility != Visibility.None).lastOption
     case _ => None
   }

   def nodes(reference: net.Node) = {
     val referenceNeighbors = neighbors(reference).toSet
     nodes.filter(node => node.visibility == Visibility.Network || referenceNeighbors.contains(node))
   }

   def nodes = nodeMap.filter(_._1 > 0).values.flatten.map(_.data).filter(_.visibility != Visibility.None)

   def neighbors(node: net.Node) = nodeMap.get(node.address) match {
     case None => throw new IllegalArgumentException("Node must be in this network.")
     case Some(list) => list.find(_.data == node) match {
       case None => throw new IllegalArgumentException("Node must be in this network.")
       case Some(n) => n.edges.map(_.other(n).data)
     }
   }

   def sendToAddress(source: net.Node, target: Int, name: String, data: Any*) =
     nodeMap.get(target) match {
       case None => None
       case Some(list) => send(new Network.Message(source, name, Array(data: _*)), list.map(_.data))
     }

   def sendToNeighbors(source: net.Node, name: String, data: Any*) =
     send(new Network.Message(source, name, Array(data: _*)), neighbors(source))

   def sendToAll(source: net.Node, name: String, data: Any*) =
     send(new Network.Message(source, name, Array(data: _*)), nodes)

   private def send(message: Network.Message, targets: Iterable[net.Node]) =
     if (message.source.address > 0 && message.source.visibility != Visibility.None) {
       def protectedSend(target: net.Node) = try {
         //println("receive(" + message.name + "(" + message.data.mkString(", ") + "): " + message.source.address + ":" + message.source.name + " -> " + target.address + ":" + target.name + ")")
         target.receive(message)
       } catch {
         case e: Throwable => OpenComputers.log.log(Level.WARNING, "Error in message handler", e); None
       }

       message match {
         case _@(Network.ConnectMessage(_) | Network.ReconnectMessage(_, _)) =>
           // Cannot be canceled but respects visibility.
           (message.source.visibility match {
             case Visibility.Neighbors =>
               // Note: the neighbors() call already filters out invalid nodes.
               val neighborSet = neighbors(message.source).toSet
               targets.filter(target => target == message.source || neighborSet.contains(target))
             case Visibility.Network =>
               targets.filter(_.address > 0).filter(_.visibility == Visibility.Network)
           }).foreach(protectedSend)
           None
         case _@Network.DisconnectMessage(_) =>
           // Cannot be canceled but ignores visibility (because it'd be a pain to implement this otherwise).
           targets.filter(_.address > 0).foreach(protectedSend)
           None
         case _ =>
           // Can be canceled but ignores visibility.
           var result = None: Option[Array[Any]]
           val iterator = targets.filter(_.address > 0).iterator
           while (!message.isCanceled && iterator.hasNext)
             protectedSend(iterator.next()) match {
               case None => // Ignore.
               case r => result = r
             }
           result
       }
     } else None

   private def findId(reserved: collection.Set[Int] = collection.Set.empty[Int]) = Range(1, Int.MaxValue).find(
     address => !nodeMap.contains(address) && !reserved.contains(address)).get
 }

 object Network {
   @ForgeSubscribe
   def onChunkUnload(e: ChunkEvent.Unload) =
     onUnload(e.world, e.getChunk.chunkTileEntityMap.values.asScala.map(_.asInstanceOf[TileEntity]))

   @ForgeSubscribe
   def onChunkLoad(e: ChunkEvent.Load) =
     onLoad(e.world, e.getChunk.chunkTileEntityMap.values.asScala.map(_.asInstanceOf[TileEntity]))

   private def onUnload(w: World, tileEntities: Iterable[TileEntity]) = if (!w.isRemote) {
     // TODO add a more efficient batch remove operation? something along the lines of if #remove > #nodes*factor remove all, re-add remaining?
     tileEntities.
       filter(_.isInstanceOf[net.Node]).
       map(_.asInstanceOf[net.Node]).
       foreach(t => t.network.foreach(_.remove(t)))
   }

   private def onLoad(w: World, tileEntities: Iterable[TileEntity]) = if (!w.isRemote) {
     tileEntities.foreach(t => joinOrCreateNetwork(w, t.xCoord, t.yCoord, t.zCoord))
   }

   def joinOrCreateNetwork(world: IBlockAccess, x: Int, y: Int, z: Int): Unit =
     getNetworkNode(world, x, y, z) match {
       case None => // Invalid block.
       case Some(node) => {
         for (side <- ForgeDirection.VALID_DIRECTIONS) {
           getNetworkNode(world, x + side.offsetX, y + side.offsetY, z + side.offsetZ) match {
             case None => // Ignore.
             case Some(neighborNode) =>
               if (neighborNode.network.isDefined) {
                 neighborNode.network.foreach(_.connect(neighborNode, node))
               }
           }
         }
         if (node.network.isEmpty) new Network(node)
       }
     }

   private def getNetworkNode(world: IBlockAccess, x: Int, y: Int, z: Int): Option[TileEntity with net.Node] =
     Option(Block.blocksList(world.getBlockId(x, y, z))) match {
       case Some(block) if block.hasTileEntity(world.getBlockMetadata(x, y, z)) =>
         world.getBlockTileEntity(x, y, z) match {
           case tileEntity: TileEntity with net.Node => Some(tileEntity)
           case _ => None
         }
       case _ => None
     }

   private class Node(val data: net.Node) {
     val edges = ArrayBuffer.empty[Edge]

     def remove() = {
       edges.foreach(edge => edge.other(this).edges -= edge)
       searchGraphs(edges.map(_.other(this)))
     }
   }

   private case class Edge(left: Node, right: Node) {
     left.edges += this
     right.edges += this

     def other(side: Node) = if (side == left) right else left

     def isBetween(a: Node, b: Node) = (a == left && b == right) || (b == left && a == right)

     def remove() = {
       left.edges -= this
       right.edges -= this
       searchGraphs(List(left, right))
     }
   }

   private def searchGraphs(seeds: Seq[Node]) = {
     val seen = mutable.Set.empty[Node]
     seeds.map(seed => {
       if (seen.contains(seed)) {
         // If our seed node is contained in another sub graph we have nothing
         // to do, since we're a sub graph of that sub graph.
         mutable.Map.empty[Int, mutable.ArrayBuffer[Node]]
       }
       else {
         // Not yet processed, start growing a network from here. We're
         // guaranteed to not find previously processed nodes, since edges
         // are bidirectional, and we'd be in the other branch otherwise.
         seen += seed
         val subGraph = mutable.Map(seed.data.address -> mutable.ArrayBuffer(seed))
         val queue = mutable.Queue(seed.edges.map(_.other(seed)): _*)
         while (queue.nonEmpty) {
           val node = queue.dequeue()
           seen += node
           subGraph.getOrElseUpdate(node.data.address, new ArrayBuffer[Node]) += node
           queue ++= node.edges.map(_.other(node)).filter(n => !seen.contains(n) && !queue.contains(n))
         }
         subGraph
       }
     }) filter (_.nonEmpty)
   }

   private class Message(@BeanProperty val source: net.Node,
                         @BeanProperty val name: String,
                         @BeanProperty val data: Array[Any] = Array()) extends net.Message {
     var isCanceled = false

     def cancel() = isCanceled = true
   }

   private case class ConnectMessage(override val source: net.Node) extends Message(source, "network.connect")

   private case class DisconnectMessage(override val source: net.Node) extends Message(source, "network.disconnect")

   private case class ReconnectMessage(override val source: net.Node, oldAddress: Int) extends Message(source, "network.reconnect", Array(oldAddress.asInstanceOf[Any]))

 }
	package li.cil.oc.server.network

	import _root_.net.minecraft.block.Block
	import _root_.net.minecraft.tileentity.TileEntity
	import _root_.net.minecraft.world.{IBlockAccess, World}
	import _root_.net.minecraftforge.common.ForgeDirection
	import _root_.net.minecraftforge.event.ForgeSubscribe
	import _root_.net.minecraftforge.event.world.ChunkEvent
	import java.util.logging.Level
	import li.cil.oc.api.network.Visibility
	import li.cil.oc.api.{network => net}
	import li.cil.oc.server.network.Network.Node
	import li.cil.oc.{api, OpenComputers}
	import scala.beans.BeanProperty
	import scala.collection.JavaConverters._
	import scala.collection.mutable
	import scala.collection.mutable.ArrayBuffer

	/**
	* Network implementation for component networks.
	*
	* This network interconnects components in a geometry-agnostic fashion. It
	* builds an internal graph of network nodes and the connections between them,
	* and takes care of merges when adding connections, as well as net splits on
	* node removal.
	*
	* It keeps the list of nodes as a lookup table for fast id->node resolving.
	* Note that it is possible for multiple nodes to have the same ID, though.
	*/
	class Network private(private val nodeMap: mutable.Map[Int, ArrayBuffer[Network.Node]]) extends api.Network {
	def this(node: net.Node) = {
	this(mutable.Map({
	if (node.address < 1)
	node.address = 1
	node.address -> ArrayBuffer(new Network.Node(node))
	}))
	send(new Network.ConnectMessage(node), List(node))
	}

	nodes.foreach(_.network = Some(this))

	def connect(nodeA: net.Node, nodeB: net.Node) = {
	val containsA = nodeMap.get(nodeA.address).exists(_.exists(_.data == nodeA))
	val containsB = nodeMap.get(nodeB.address).exists(_.exists(_.data == nodeB))
	if (!containsA && !containsB) throw new IllegalArgumentException(
	"At least one of the nodes must already be in this network.")

	def oldNodeA = nodeMap(nodeA.address).find(_.data == nodeA).get
	def oldNodeB = nodeMap(nodeB.address).find(_.data == nodeB).get
	if (containsA && containsB) {
	// Both nodes already exist in the network but there is a new connection.
	// This can happen if a new node sequentially connects to multiple nodes
	// in an existing network, e.g. in a setup like so:
	// O O Where O is an old node, and N is the new Node. It would connect
	// O N to the node above and left to it (in no particular order).
	if (!oldNodeA.edges.exists(_.isBetween(oldNodeA, oldNodeB))) {
	assert(!oldNodeB.edges.exists(_.isBetween(oldNodeA, oldNodeB)))
	Network.Edge(oldNodeA, oldNodeB)
	true
	}
	// That connection already exists.
	else false
	}
	// New node for this network, order the nodes and add the new one.
	else if (containsA) add(oldNodeA, nodeB)
	else add(oldNodeB, nodeA)
	}

	private def add(oldNode: Network.Node, addedNode: net.Node) = {
	// Check if the other node is new or if we have to merge networks.
	val (newNode, sendQueue) = if (addedNode.network.isEmpty) {
	val newNode = new Network.Node(addedNode)
	if (nodeMap.contains(addedNode.address) \|\| addedNode.address < 1)
	addedNode.address = findId()
	// Store everything with an invalid address in slot zero.
	val address = addedNode.address match {
	case a if a > 0 => a
	case _ => 0
	}
	// Create the message queue. The address check is purely for performance,
	// since we can skip all that if the node is non-valid.
	val sendQueue = mutable.Buffer.empty[(Network.Message, Iterable[net.Node])]
	if (address > 0 && addedNode.visibility != Visibility.None) {
	sendQueue += ((new Network.ConnectMessage(addedNode), List(addedNode) ++ nodes))
	nodes.foreach(node => sendQueue += ((new Network.ConnectMessage(node), List(addedNode))))
	}
	nodeMap.getOrElseUpdate(address, new ArrayBuffer[Network.Node]) += newNode
	addedNode.network = Some(this)
	(newNode, sendQueue)
	}
	else {
	// Queue any messages to avoid side effects from receivers.
	val sendQueue = mutable.Buffer.empty[(Network.Message, Iterable[net.Node])]
	val thisNodes = nodes.toBuffer
	val otherNetwork = addedNode.network.get.asInstanceOf[Network]
	val otherNodes = otherNetwork.nodes.toBuffer
	otherNodes.foreach(node => sendQueue += ((Network.ConnectMessage(node), thisNodes)))
	thisNodes.foreach(node => sendQueue += ((Network.ConnectMessage(node), otherNodes)))

	// Change addresses for conflicting nodes in other network. We can queue
	// these messages because we're storing references to the nodes, so they
	// will send the change notification to the right node even if that node
	// also changes its address.
	val reserved = mutable.Set(otherNetwork.nodeMap.keySet.toSeq: _*)
	otherNodes.filter(node => nodeMap.contains(node.address)).foreach(node => {
	val oldAddress = node.address
	node.address = findId(reserved)
	if (node.address != oldAddress) {
	reserved += node.address
	// Prepend to notify old nodes of address changes first.
	sendQueue.+=:((Network.ReconnectMessage(node, oldAddress), otherNodes))
	}
	})

	// Add nodes from other network into this network, including invalid nodes.
	otherNetwork.nodeMap.values.flatten.foreach(node => {
	nodeMap.getOrElseUpdate(node.data.address, new ArrayBuffer[Network.Node]) += node
	node.data.network = Some(this)
	})

	// Return the node object of the newly connected node for the next step.
	(nodeMap(addedNode.address).find(_.data == addedNode).get, sendQueue)
	}

	// Add the connection between the two nodes.
	Network.Edge(oldNode, newNode)

	// Send all generated messages.
	for ((message, nodes) <- sendQueue) send(message, nodes)

	true
	}

	def reconnect(node: net.Node, address: Int): Boolean = {
	if (!nodeMap.get(node.address).exists(_.exists(_.data == node))) throw new IllegalArgumentException(
	"The node must already be in this network.")

	val oldAddress = node.address
	if (address == oldAddress) false
	else {
	val otherMessage = if (address < 1) {
	node.address = 0
	None
	}
	else {
	// Check if there's a simple collision, if so resolve it.
	nodeMap.get(address) match {
	case None =>
	// No collision.
	node.address = address
	None
	case Some(otherList) =>
	if (otherList.size > 1)
	return false // Already multiple nodes with that address...
	else {
	// Simple collision.
	val other = otherList.head
	otherList -= other

	other.data.address = findId()
	nodeMap.getOrElseUpdate(other.data.address, new mutable.ArrayBuffer[Node]) += other
	Some((Network.ReconnectMessage(other.data, address), nodes))
	}
	}
	}

	val oldList = nodeMap(oldAddress)
	val innerNode = oldList.remove(oldList.indexWhere(_.data == node))
	if (oldList.isEmpty)
	nodeMap -= oldAddress
	nodeMap.getOrElseUpdate(node.address, new mutable.ArrayBuffer[Node]) += innerNode

	otherMessage.foreach {
	case (message, targets) => send(message, targets)
	}
	send(Network.ReconnectMessage(node, oldAddress), nodes)

	true
	}
	}

	def disconnect(nodeA: net.Node, nodeB: net.Node) = {
	val containsA = nodeMap.get(nodeA.address).exists(_.exists(_.data == nodeA))
	val containsB = nodeMap.get(nodeB.address).exists(_.exists(_.data == nodeB))
	if (!containsA \|\| !containsB) throw new IllegalArgumentException(
	"Both of the nodes must be in this network.")

	def oldNodeA = nodeMap(nodeA.address).find(_.data == nodeA).get
	def oldNodeB = nodeMap(nodeB.address).find(_.data == nodeB).get
	oldNodeA.edges.find(_.isBetween(oldNodeA, oldNodeB)) match {
	case None => false // That connection doesn't exists.
	case Some(edge) => {
	handleSplit(edge.remove())
	true
	}
	}
	}

	def remove(node: net.Node) = nodeMap.get(node.address) match {
	case None => false
	case Some(list) => list.find(_.data == node) match {
	case None => false
	case Some(entry) => {
	node.network = None

	// Removing a node may result in a net split, leaving us with multiple
	// networks. The remove function returns all resulting networks, one
	// of which we'll re-use for this network. For all additional ones we
	// create new network instances.
	handleSplit(entry.remove(), nodes => {
	nodes.foreach(n => send(new Network.DisconnectMessage(n), List(node)))
	send(new Network.DisconnectMessage(node), nodes)
	})
	send(new Network.DisconnectMessage(node), List(node))
	true
	}
	}
	}

	private def handleSplit(subGraphs: Seq[mutable.Map[Int, ArrayBuffer[Network.Node]]],
	messageCallback: Iterable[net.Node] => Unit = _ => {}) = {
	// Sending the removal messages can have side effects, so we'll keep a
	// copy of the original list of nodes in each sub network.
	val subNodes = subGraphs.map(_.values.flatten.map(_.data).toBuffer).toBuffer

	// We re-use this network by assigning the first sub graph to it. For
	// all additional sub graphs (if any) we'll have to create new ones.
	nodeMap.clear()
	// Empty for the last node removed from a network.
	if (!subGraphs.isEmpty) {
	nodeMap ++= subGraphs.head
	subGraphs.tail.foreach(new Network(_))
	}

	// Send removal messages. First, to the removed node itself (for its
	// onDisconnect handler), then one for the removed node to all sub
	// networks, for each node in the sub networks back to the removed node
	// and if there was a net split (we have multiple networks) also for
	// each node now longer belonging to one of the resulting sub networks.
	for (indexA <- 0 until subNodes.length) {
	val nodesA = subNodes(indexA)
	for (indexB <- (indexA + 1) until subNodes.length) {
	val nodesB = subNodes(indexB)
	nodesA.foreach(nodeA => send(new Network.DisconnectMessage(nodeA), nodesB))
	nodesB.foreach(nodeB => send(new Network.DisconnectMessage(nodeB), nodesA))
	}
	messageCallback(nodesA)
	}
	}

	def node(address: Int) = nodeMap.get(address) match {
	case Some(list) if address > 0 => list.map(_.data).filter(_.visibility != Visibility.None).lastOption
	case _ => None
	}

	def nodes(reference: net.Node) = {
	val referenceNeighbors = neighbors(reference).toSet
	nodes.filter(node => node.visibility == Visibility.Network \|\| referenceNeighbors.contains(node))
	}

	def nodes = nodeMap.filter(_._1 > 0).values.flatten.map(_.data).filter(_.visibility != Visibility.None)

	def neighbors(node: net.Node) = nodeMap.get(node.address) match {
	case None => throw new IllegalArgumentException("Node must be in this network.")
	case Some(list) => list.find(_.data == node) match {
	case None => throw new IllegalArgumentException("Node must be in this network.")
	case Some(n) => n.edges.map(_.other(n).data)
	}
	}

	def sendToAddress(source: net.Node, target: Int, name: String, data: Any*) =
	nodeMap.get(target) match {
	case None => None
	case Some(list) => send(new Network.Message(source, name, Array(data: _*)), list.map(_.data))
	}

	def sendToNeighbors(source: net.Node, name: String, data: Any*) =
	send(new Network.Message(source, name, Array(data: _*)), neighbors(source))

	def sendToAll(source: net.Node, name: String, data: Any*) =
	send(new Network.Message(source, name, Array(data: _*)), nodes)

	private def send(message: Network.Message, targets: Iterable[net.Node]) =
	if (message.source.address > 0 && message.source.visibility != Visibility.None) {
	def protectedSend(target: net.Node) = try {
	//println("receive(" + message.name + "(" + message.data.mkString(", ") + "): " + message.source.address + ":" + message.source.name + " -> " + target.address + ":" + target.name + ")")
	target.receive(message)
	} catch {
	case e: Throwable => OpenComputers.log.log(Level.WARNING, "Error in message handler", e); None
	}

	message match {
	case _@(Network.ConnectMessage(_) \| Network.ReconnectMessage(_, _)) =>
	// Cannot be canceled but respects visibility.
	(message.source.visibility match {
	case Visibility.Neighbors =>
	// Note: the neighbors() call already filters out invalid nodes.
	val neighborSet = neighbors(message.source).toSet
	targets.filter(target => target == message.source \|\| neighborSet.contains(target))
	case Visibility.Network =>
	targets.filter(_.address > 0).filter(_.visibility == Visibility.Network)
	}).foreach(protectedSend)
	None
	case _@Network.DisconnectMessage(_) =>
	// Cannot be canceled but ignores visibility (because it'd be a pain to implement this otherwise).
	targets.filter(_.address > 0).foreach(protectedSend)
	None
	case _ =>
	// Can be canceled but ignores visibility.
	var result = None: Option[Array[Any]]
	val iterator = targets.filter(_.address > 0).iterator
	while (!message.isCanceled && iterator.hasNext)
	protectedSend(iterator.next()) match {
	case None => // Ignore.
	case r => result = r
	}
	result
	}
	} else None

	private def findId(reserved: collection.Set[Int] = collection.Set.empty[Int]) = Range(1, Int.MaxValue).find(
	address => !nodeMap.contains(address) && !reserved.contains(address)).get
	}

	object Network {
	@ForgeSubscribe
	def onChunkUnload(e: ChunkEvent.Unload) =
	onUnload(e.world, e.getChunk.chunkTileEntityMap.values.asScala.map(_.asInstanceOf[TileEntity]))

	@ForgeSubscribe
	def onChunkLoad(e: ChunkEvent.Load) =
	onLoad(e.world, e.getChunk.chunkTileEntityMap.values.asScala.map(_.asInstanceOf[TileEntity]))

	private def onUnload(w: World, tileEntities: Iterable[TileEntity]) = if (!w.isRemote) {
	// TODO add a more efficient batch remove operation? something along the lines of if #remove > #nodes*factor remove all, re-add remaining?
	tileEntities.
	filter(_.isInstanceOf[net.Node]).
	map(_.asInstanceOf[net.Node]).
	foreach(t => t.network.foreach(_.remove(t)))
	}

	private def onLoad(w: World, tileEntities: Iterable[TileEntity]) = if (!w.isRemote) {
	tileEntities.foreach(t => joinOrCreateNetwork(w, t.xCoord, t.yCoord, t.zCoord))
	}

	def joinOrCreateNetwork(world: IBlockAccess, x: Int, y: Int, z: Int): Unit =
	getNetworkNode(world, x, y, z) match {
	case None => // Invalid block.
	case Some(node) => {
	for (side <- ForgeDirection.VALID_DIRECTIONS) {
	getNetworkNode(world, x + side.offsetX, y + side.offsetY, z + side.offsetZ) match {
	case None => // Ignore.
	case Some(neighborNode) =>
	if (neighborNode.network.isDefined) {
	neighborNode.network.foreach(_.connect(neighborNode, node))
	}
	}
	}
	if (node.network.isEmpty) new Network(node)
	}
	}

	private def getNetworkNode(world: IBlockAccess, x: Int, y: Int, z: Int): Option[TileEntity with net.Node] =
	Option(Block.blocksList(world.getBlockId(x, y, z))) match {
	case Some(block) if block.hasTileEntity(world.getBlockMetadata(x, y, z)) =>
	world.getBlockTileEntity(x, y, z) match {
	case tileEntity: TileEntity with net.Node => Some(tileEntity)
	case _ => None
	}
	case _ => None
	}

	private class Node(val data: net.Node) {
	val edges = ArrayBuffer.empty[Edge]

	def remove() = {
	edges.foreach(edge => edge.other(this).edges -= edge)
	searchGraphs(edges.map(_.other(this)))
	}
	}

	private case class Edge(left: Node, right: Node) {
	left.edges += this
	right.edges += this

	def other(side: Node) = if (side == left) right else left

	def isBetween(a: Node, b: Node) = (a == left && b == right) \|\| (b == left && a == right)

	def remove() = {
	left.edges -= this
	right.edges -= this
	searchGraphs(List(left, right))
	}
	}

	private def searchGraphs(seeds: Seq[Node]) = {
	val seen = mutable.Set.empty[Node]
	seeds.map(seed => {
	if (seen.contains(seed)) {
	// If our seed node is contained in another sub graph we have nothing
	// to do, since we're a sub graph of that sub graph.
	mutable.Map.empty[Int, mutable.ArrayBuffer[Node]]
	}
	else {
	// Not yet processed, start growing a network from here. We're
	// guaranteed to not find previously processed nodes, since edges
	// are bidirectional, and we'd be in the other branch otherwise.
	seen += seed
	val subGraph = mutable.Map(seed.data.address -> mutable.ArrayBuffer(seed))
	val queue = mutable.Queue(seed.edges.map(_.other(seed)): _*)
	while (queue.nonEmpty) {
	val node = queue.dequeue()
	seen += node
	subGraph.getOrElseUpdate(node.data.address, new ArrayBuffer[Node]) += node
	queue ++= node.edges.map(_.other(node)).filter(n => !seen.contains(n) && !queue.contains(n))
	}
	subGraph
	}
	}) filter (_.nonEmpty)
	}

	private class Message(@BeanProperty val source: net.Node,
	@BeanProperty val name: String,
	@BeanProperty val data: Array[Any] = Array()) extends net.Message {
	var isCanceled = false

	def cancel() = isCanceled = true
	}

	private case class ConnectMessage(override val source: net.Node) extends Message(source, "network.connect")

	private case class DisconnectMessage(override val source: net.Node) extends Message(source, "network.disconnect")

	private case class ReconnectMessage(override val source: net.Node, oldAddress: Int) extends Message(source, "network.reconnect", Array(oldAddress.asInstanceOf[Any]))

	}