Package com.microstrategy.utils

Class DAG

  • public class DAG
extends java.lang.Object
    This class represents a generic Directed Acyclic Graph. There are a number of inner classes that represent the parts of this DAG:
    • DAG.Vertex represents a vertex in this graph.
    • DAG.Edge represents an edge in this graph that connects two vertices.
    Since:
    MicroStrategy Web 9.0.0
    See Also:
    DAG.Vertex, DAG.Edge

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  DAG.AnnotatableObject
      This is a simple object which can be "annotated" with caller-specified properties.
      static class  DAG.Edge
      This class represents an Edge in the Directed Acyclic Graph.
      static class  DAG.Vertex
      This class represents an end point ("vertex") in a Directed Acyclic Graph.

    • Constructor Summary

      Constructors 
      Constructor Description
      DAG()  

    • Constructor Detail

      • DAG

        public DAG()

    • Method Detail

      • addEdge

        public DAG.Edge addEdge​(DAG.Vertex fromVertex,
                        DAG.Vertex toVertex)
        Adds an edge between two vertices. If an edge already exists between these vertices, it is returned.
        Parameters:
        fromVertex - The DAG.Vertex that represents the "from" end.
        toVertex - The DAG.Vertex that represents the "to" end.
        Returns:
        An existing DAG.Edge (if one exists) or a newly created one that joins the two vertices.

      • getEdge

        public DAG.Edge getEdge​(DAG.Vertex fromVertex,
                        DAG.Vertex toVertex)
        Returns an Edge object which connects two Vertices. If not found, then null is returned.
        Parameters:
        fromVertex - The DAG.Vertex which is the "from" end.
        toVertex - The DAG.Vertex which is the "to" end.
        Returns:
        Either the DAG.Edge, if it exists, or null.

      • getVertex

        public DAG.Vertex getVertex​(java.lang.String vertexKey,
                            boolean create)
        Returns the Vertex associated with the supplied key.
        Parameters:
        vertexKey - The key for the Vertex to return.
        create - If true and no Vertex was found, then a new Vertex object is created and returned. Otherwise, null is returned.
        Returns:
        The DAG.Vertex associated with this key (or a new one if 'create' is true) or null.

      • getVertices

        public java.util.Iterator<DAG.Vertex> getVertices()
        Returns all of the Vertices in this DAG.
        Returns:
        An Iterator of DAG.Vertex objects.

      • getEdges

        public java.util.Iterator<DAG.Edge> getEdges()
        Returns all of the Edges in this DAG.
        Returns:
        An Iterator of DAG.Edge objects.

      • getMessageRouter

        public MessageRouter getMessageRouter()
        Returns the Message Router instance to use with this DAG.
        Returns:
        The Message Router instance to use with this DAG.

      • setMessageRouter

        public void setMessageRouter​(MessageRouter msgRouter)
        Sets the Message Router instance to use with this DAG.
        Parameters:
        msgRouter - The Message Router instance to use with this DAG.

      • topoSort

        public java.util.Iterator<DAG.Vertex> topoSort()
        Performs a topological sort on the contents of this DAG. The results are a list of Vertices that satisfies this partial ordering.
        Returns:
        A Iterator of DAG.Vertex objects.

      • sinkVertices

        public java.util.Iterator<DAG.Vertex> sinkVertices()
        Returns the list of sink vertices in the DAG. A sink vertex is a vertex without an out bound edge. A DAG should contain at least one sink vertex.
        Returns:
        A Iterator of DAG.Vertex objects.