Package com.saxonica.xsltextn.pedigree

Class Pedigree

  • public class Pedigree
extends java.lang.Object
    A Pedigree is transient information relating to a map or array indicating the route by which it was reached; it thus compensates for the absence of parent pointers in a JSON-like tree, by allowing the steps used to reach a map or array in such a structure to be retraced.

    A map or array that has a Pedigree is represented by a PedigreeValue, which is a combination of the map/array and the Pedigree. The Pedigree holds a reference to the "container" PedigreeValue from which this map or array was reached, and the key or index value within that container.

    Note that maps and arrays have no externally visible identity. It is not meaningful to ask whether the same map can be reached by two different routes, because there is no way to establish "sameness".

    A map or array will have a Pedigree if it is found by downwards selection from a map or array that itself has a Pedigree, or if it was explicitly created with a Pedigree.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static Pedigree PEDIGREE_ROOT
      An empty Pedigree: that is, the Pedigree of a map or array that was created as the root of a pedigree tree.

    • Constructor Summary

      Constructors 
      Constructor Description
      Pedigree​(PedigreeValue container, int index)
      Create a pedigree for a map or array obtained by selection from an array, using an index value as a subscript into the array
      Pedigree​(PedigreeValue container, AtomicValue key)
      Create a pedigree for a map or array obtained by selection from a map, using a key value

    • Field Detail

      • PEDIGREE_ROOT

        public static final Pedigree PEDIGREE_ROOT
        An empty Pedigree: that is, the Pedigree of a map or array that was created as the root of a pedigree tree.

    • Constructor Detail

      • Pedigree

        public Pedigree​(PedigreeValue container,
                AtomicValue key)
        Create a pedigree for a map or array obtained by selection from a map, using a key value
        Parameters:
        container - the containing map
        key - the key value used to select an entry in the containing map

      • Pedigree

        public Pedigree​(PedigreeValue container,
                int index)
        Create a pedigree for a map or array obtained by selection from an array, using an index value as a subscript into the array
        Parameters:
        container - the containing map
        index - the zero-based index value used to select a member of the containing array

    • Method Detail

      • getContainer

        public PedigreeValue getContainer()
        Get the containing map or array
        Returns:
        the containing map or array

      • getIndex

        public int getIndex()
        Get the index if this item was obtained by selection from an array
        Returns:
        the zero-based index if this item was obtained by selection from an array, otherwise -1.

      • getKey

        public AtomicValue getKey()
        Get the key if this item was obtained by selection from a map
        Returns:
        the key if this item was obtained by selection from a map, otherwise null.

      • makePedigreeValue

        public GroundedValue makePedigreeValue​(GroundedValue value)
        Make a map or array that combines a supplied map or array with this pedigree
        Parameters:
        value - the supplied value
        Returns:
        if the supplied value is a map or array, returns a map or array augmented with this pedigree. Otherwise, returns the supplied value unchanged.