I'm working on my Scala chops and implemented a small graph API to track vertices and edges added to graph. I have basic GraphLike Trait, and have an Undirected Graph class ( UnDiGraph) and a Directed graph class (DiGraph ) that extend the GraphLike trait.Here is some of the listing:trait GraphLike[T] {    val vertices: Map[T, VertexLike[T]]    def addEdge( a:T, b:T ): GraphLike[T]    def addVertex( t:T ): GraphLike[T]    def addVertex( vert: VertexLike[T] ): GraphLike[T]    def adjacency( t:T ): Option[ List[T] ]  =    {      if ( vertices contains t )        Some( vertices(t).adjList )      else        None    }    def vertNum: Integer = vertices size    def edgeNum: Integer =     {      def summer( sum: Integer, ms: Map[T, VertexLike[T] ] ): Integer =      {        if ( ms.isEmpty )          sum        else          summer( sum + ms.head._2.adjList.size, ms.tail )      }      summer( 0, vertices )    }    def getVertex( t: T ): VertexLike[T] =    {      vertices( t )    }    def edgeExists( a:T, b:T ): Boolean =    {      try      {          if( vertices( a ).adjList contains b )            true          else            false      }catch {        case ex: NoSuchElementException => false       }    }}Here's what the DiGraph looks like:class DiGraph[T](val vertices: Map[ T, VertexLike[ T ] ] = Map.empty ) extends GraphLike[T] {    def makeVertex( t:T ): VertexLike[T] = new Vertex( t )    def addEdge( a:T, b:T ): GraphLike[T] =    {      //Make sure vertices exist      if( edgeExists(a, b) )        this      else {        try {          vertices(b)          vertices(a)        } catch {          case ex: NoSuchElementException => println(Vertices not Found); this        }        addVertex( vertices( a ) + b )      }    }    def addVertex( t:T ): DiGraph[T] =     {      if( vertices contains t ) this      else      new DiGraph[T]( vertices + ( t -> makeVertex(t) ) )    }    def addVertex( vert: VertexLike[T] ): DiGraph[T] =    {      new DiGraph[T]( vertices + ( vert.apply -> vert ) )     }}Vertices are stored in a Map going from type T to VertexLike[T]. VertexLike basically holds an adjacency list for the specific Vertex.Here's what VertexLike looks like:trait VertexLike[T] {  def addEdgeTo( dest: T ): VertexLike[T]  def adjList: List[T]  def +( dest: T) = addEdgeTo(dest)  def apply: T} class Vertex[T](t: T, adj: List[T] = List() ) extends VertexLike[T]{    def apply() = t    def adjList = adj    def addEdgeTo( dest: T ) =       if( adjList contains dest )        this      else        new Vertex[T]( t, dest :: adjList )}(Yes, I realize the apply method in the class is useless and it only works on objects.  I realized that a little later). Anyways, I have a sample graph where I have about 80,000 vertices. Adding the vertices to the Graph is taking just way too long. I tried to do things functionally and in an immutable way. Whenever you add a vertex or an edge to a graph, you get a new graph (I tried to make sure the constructors of the graph types weren't doing much). This is the client code that I use to create my graph from my data.def GraphInstantiater: GraphLike[Int] ={  println( Total number of Vertices:  + synMap.keys.size )  def vertexAdder( ls: Iterable[Int], graph:GraphLike[Int] ): GraphLike[Int] =     if( ls.isEmpty) graph else vertexAdder( ls.tail, graph.addVertex( ls.head ) )   val gr = vertexAdder( synMap.keys, new DiGraph[Int]( Map() ) )  println( Vertices added. Total: %d.format( gr.vertices.size ) )  gr}I know constructing new graphs will take cycles but is it really all that great given that I'm not doing much in the constructors. Would repeatedly creating the Map of vertices keep causing problems (it's one of the parameters of the graph class). Any ideas on what the bottlenecks are in this method would be much appreciated.
Small graph API to track vertices and edges added to graph
performance;scala;graph