Package org.jparsec

Class TreeNode

  • final class TreeNode
extends java.lang.Object
    A TreeNode remembers it's parent (which corresponds to a parent parser that syntactically encloses this parter), it's previous node (which is the parser at the same syntactical level and had just succeeded before this parser started). It also keeps all the children.

    Once constructed, a node's 'parent' and 'previous' references are immutable. The list of children nodes however can change. When the alternative parsers in an or parser are attempted one after another, they each generate new child node of the parent node. These "alternative" nodes all point to the same parent and same "previous" node.

    When exception is to be thrown, the most relevant error is picked, along with the tree node that was recorded at time of ParseContext.raise(org.jparsec.ParseContext.ErrorType, java.lang.Object). That tree node is then frozen by setting its parent's latestChild to this error node's "previous" successful node, and that of its grandparent's to its parent node, all the way up to the root. This essentially freezes and collapse the "multi universes" into a single error state, with all other "potential" error state destroyed and forgotten.

    • Constructor Summary

      Constructors 
      Constructor Description
      TreeNode​(java.lang.String name, int beginIndex)  
      TreeNode​(java.lang.String name, int beginIndex, TreeNode parent, TreeNode previous)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      (package private) TreeNode addChild​(java.lang.String childName, int childIndex)  
      (package private) TreeNode freeze​(int index)
      Freezes the current tree node to make it the latest child of its parent (discarding nodes that have been tacked on after it in the same hierarchy level); and recursively apply to all of its ancestors.
      (package private) TreeNode orphanize()
      When this leaf node has errors, it didn't complete and shouldn't be part of the parse tree that is the current partial parse result with all successful matches.
      (package private) TreeNode parent()  
      (package private) void setEndIndex​(int index)  
      (package private) void setResult​(java.lang.Object result)  
      (package private) ParseTree toParseTree()
      Converts this node into a ParseTree representation.
      java.lang.String toString()  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    • Field Detail

      • name

        private final java.lang.String name

      • beginIndex

        private final int beginIndex

      • previous

        private final TreeNode previous

      • endIndex

        private int endIndex

      • result

        private java.lang.Object result

    • Constructor Detail

      • TreeNode

        TreeNode​(java.lang.String name,
         int beginIndex)

      • TreeNode

        TreeNode​(java.lang.String name,
         int beginIndex,
         TreeNode parent,
         TreeNode previous)

    • Method Detail

      • setEndIndex

        void setEndIndex​(int index)

      • setResult

        void setResult​(java.lang.Object result)

      • addChild

        TreeNode addChild​(java.lang.String childName,
                  int childIndex)

      • orphanize

        TreeNode orphanize()
        When this leaf node has errors, it didn't complete and shouldn't be part of the parse tree that is the current partial parse result with all successful matches. In that case, return the parent node, by setting its latestChild to previous.

      • freeze

        TreeNode freeze​(int index)
        Freezes the current tree node to make it the latest child of its parent (discarding nodes that have been tacked on after it in the same hierarchy level); and recursively apply to all of its ancestors.

        This is because it's only called at time of error. If an ancestor node has a child node that was added during the process of trying other alternatives and then failed, those paths don't matter. So we should restore the tree back to when this most relevant error happened.

        Returns the root node, which can then be used to toParseTree().

      • toParseTree

        ParseTree toParseTree()
        Converts this node into a ParseTree representation.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object