Package org.gcube.informationsystem.dag

Class Dag<T>

java.lang.Object
org.gcube.informationsystem.dag.Dag<T>
Type Parameters:
T - The type of the elements stored in the graph.
public class Dag<T> extends Object
A single-rooted, directed, acyclic graph (DAG) -- typically a tree in practice (single inheritance), but genuinely a DAG whenever allowMultipleInheritance produces a node with more than one parent (see Node.getParents()): each node has exactly one identity, reachable through every parent that legitimately leads to it.
Author:
Luca Frosini (ISTI - CNR)

  • Constructor Details

    • Dag

      public Dag()
      Constructs an empty DAG.

    • Dag

      public Dag(NodeInformation<T> ni)
      Constructs a DAG with the given node information provider.
      Parameters:
      ni - The node information provider.

    • Dag

      public Dag(T root, NodeInformation<T> ni)
      Constructs a DAG with the given root element and node information provider.
      Parameters:
      root - The root element.
      ni - The node information provider.

  • Method Details

    • setNodeInformation

      public void setNodeInformation(NodeInformation<T> ni)
      Sets the node information provider for this DAG, if not already set.
      Parameters:
      ni - The node information provider.

    • setRoot

      public void setRoot(T root) throws RuntimeException
      Sets the root element of this DAG, if not already set.
      Parameters:
      root - The root element.
      Throws:
      RuntimeException - if the node information provider has not been set.

    • setAllowMultipleInheritance

      public void setAllowMultipleInheritance(boolean allowMultipleInheritance)
      Sets whether multiple inheritance is allowed in this DAG.
      Parameters:
      allowMultipleInheritance - true to allow multiple inheritance.

    • getNodeInformation

      public NodeInformation<T> getNodeInformation()
      Returns the node information provider for this DAG.
      Returns:
      The node information provider.

    • addNode

      public Node<T> addNode(T t)
      Adds a new node to the DAG.
      Parameters:
      t - The element to add.
      Returns:
      The newly created or existing node for the element.

    • getRootNode

      public Node<T> getRootNode()
      Returns the root node of the DAG.
      Returns:
      The root node.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • elaborate

      public void elaborate(NodeElaborator<T> nodeElaborator) throws Exception
      Traverses the DAG and applies the given elaborator to each node.
      Parameters:
      nodeElaborator - The elaborator to apply.
      Throws:
      Exception - if an error occurs during elaboration.

    • getNodeByIdentifier

      public Node<T> getNodeByIdentifier(String identifier)
      Returns the node with the given identifier.
      Parameters:
      identifier - The identifier of the node.
      Returns:
      The node, or null if not found.

    • isChildOf

      public boolean isChildOf(String referenceIdentifier, String requiredChild)
      Checks if a node is a child of another node.
      Parameters:
      referenceIdentifier - The identifier of the potential parent node.
      requiredChild - The identifier of the potential child node.
      Returns:
      true if the second node is a child of the first.

    • isParentOf

      public boolean isParentOf(String referenceIdentifier, String requiredParent)
      Checks if a node is a parent of another node.
      Parameters:
      referenceIdentifier - The identifier of the potential child node.
      requiredParent - The identifier of the potential parent node.
      Returns:
      true if the second node is a parent of the first.