Module: SimpleTree

Defined in:
lib/simple_tree.rb

Overview

Ruby Tree Interface by Jason M. Adams. Distributed under the BSD license, please see LICENSE for more information.

To use this interface, drop it in your current class with include. You must then simply implement the parent and children methods.

* +parent+ returns the parent node of the current node or else nil if it's a root
* +children+ returns an +Array+ of all children of this node or an empty +Array+ if it is a leaf node

Instance Method Summary collapse

Instance Method Details

#children ⇒ Object 



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# File 'lib/simple_tree.rb', line 11

def children() raise "children must be overridden"; end

#descendants ⇒ Object

Return an array containing every descendant of the current node.



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# File 'lib/simple_tree.rb', line 100

def descendants
  d = Array.new

  children.each do |child|
    d << child
    d << child.descendants
  end

  d.flatten
end

#family ⇒ Object

Return every node descending from this node’s parent (except this node). This include all of the node’s descendants.



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# File 'lib/simple_tree.rb', line 85

def family
  if parent
    fam = [parent] + parent.descendants
  else
    fam = descendants
  end

  fam.delete(self)
  fam
end

#grandparent ⇒ Object

Return the grandparent of this node.



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# File 'lib/simple_tree.rb', line 115

def grandparent
  parent.parent if parent     # returns nil by default if no parent
end

#has_children? ⇒ Boolean

Determine whether the node has children.

Returns:

  • (Boolean) 


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# File 'lib/simple_tree.rb', line 49

def has_children?
  not is_leaf?
end

#has_parent? ⇒ Boolean

Determine whether the node has a parent.

Returns:

  • (Boolean) 


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# File 'lib/simple_tree.rb', line 41

def has_parent?
  not is_root?
end

#height ⇒ Object

Return the height of this subtree. A single node has height 1.



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# File 'lib/simple_tree.rb', line 57

def height
  heights = children.map {|child| child.height}
  return 1 if heights.size == 0
  return heights.max + 1
end

#is_leaf? ⇒ Boolean

Return whether this node is a leaf node in the hierarchy.

Returns:

  • (Boolean) 


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# File 'lib/simple_tree.rb', line 17

def is_leaf?
  if children.size == 0
    true
  else
    false
  end
end

#is_root? ⇒ Boolean

Determine whether this is the root node in the hierarchy.

Returns:

  • (Boolean) 


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# File 'lib/simple_tree.rb', line 29

def is_root?
  if parent
    false
  else
    true
  end
end

#leaves ⇒ Object

Return all the leaf nodes having the current node as an ancestor.



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# File 'lib/simple_tree.rb', line 123

def leaves
  outp = Array.new
  children.each do |child|
    if child.is_leaf?
      outp << child
    else
      outp << child.leaves
    end
  end

  outp.flatten
end

#parent ⇒ Object 



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# File 'lib/simple_tree.rb', line 10

def parent() raise "parent must be overridden"; end

#siblings ⇒ Object

Return an array containing the siblings of the current node.



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# File 'lib/simple_tree.rb', line 67

def siblings
  # handle case where this is the root node
  return Array.new unless parent

  sibs = Array.new
  parent.children.each do |child|
    next if child.id == self.id
    sibs << child
  end

  sibs
end

#tree_rep(depth = 0) ⇒ Object

Helper method for to_s, returns a tree representation of the subtree rooted at this node. This assumes some sort of identifier is specified for the object being called (self.name, self.identifier, etc)



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# File 'lib/simple_tree.rb', line 142

def tree_rep(depth=0)
  if self.name
    ident = self.name
  elsif self.identifier
    ident = self.identifier
  else
    ident = self.object_id
  end
  if depth > 0
    outp = " #{(["    "] * (depth - 1)).join("|")}\\- #{ident}\n"
  else
    outp = "#{ident}\n"
  end
  children.each do |child|
    outp += child.tree_rep(depth + 1)
  end
  outp
end