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require "rexml/child"
module REXML
# A parent has children, and has methods for accessing them. The Parent
# class is never encountered except as the superclass for some other
# object.
class Parent < Child
include Enumerable
# Constructor
# @param parent if supplied, will be set as the parent of this object
def initialize parent=nil
super(parent)
@children = []
end
def add( object )
begin
object.parent = self
@children << object
rescue Exception
raise "#{$!.message}: only Child-ren can be added to a Parent"
end
object
end
alias :push :add
alias :<< :push
def unshift( object )
object.parent = self
@children.unshift object
end
def delete( object )
return unless @children.include? object
@children.delete object
object.parent = nil
end
def each(&block)
@children.each(&block)
end
def delete_if( &block )
@children.delete_if(&block)
end
def delete_at( index )
@children.delete_at index
end
def each_index( &block )
@children.each_index(&block)
end
# Fetches a child at a given index
# @param index the Integer index of the child to fetch
def []( index )
@children[index]
end
alias :each_child :each
# Set an index entry. See Array.[]=
# @param index the index of the element to set
# @param opt either the object to set, or an Integer length
# @param child if opt is an Integer, this is the child to set
# @return the parent (self)
def []=( *args )
args[-1].parent = self
@children[*args[0..-2]] = args[-1]
end
# Inserts an child before another child
# @param child1 this is either an xpath or an Element. If an Element,
# child2 will be inserted before child1 in the child list of the parent.
# If an xpath, child2 will be inserted before the first child to match
# the xpath.
# @param child2 the child to insert
# @return the parent (self)
def insert_before( child1, child2 )
if child1.kind_of? String
child1 = XPath.first( self, child1 )
child1.parent.insert_before child1, child2
else
ind = index(child1)
@children[ind,0] = child2
child2.parent = self
end
self
end
# Inserts an child after another child
# @param child1 this is either an xpath or an Element. If an Element,
# child2 will be inserted after child1 in the child list of the parent.
# If an xpath, child2 will be inserted after the first child to match
# the xpath.
# @param child2 the child to insert
# @return the parent (self)
def insert_after( child1, child2 )
if child1.kind_of? String
child1 = XPath.first( self, child1 )
child1.parent.insert_after child1, child2
else
ind = index(child1)+1
@children[ind,0] = child2
child2.parent = self
end
self
end
def to_a
@children.dup
end
# Fetches the index of a given child
# @param child the child to get the index of
# @return the index of the child, or nil if the object is not a child
# of this parent.
def index( child )
count = -1
@children.find { |i| count += 1 ; i.hash == child.hash }
count
end
# @return the number of children of this parent
def size
@children.size
end
# Replaces one child with another, making sure the nodelist is correct
# @param to_replace the child to replace (must be a Child)
# @param replacement the child to insert into the nodelist (must be a
# Child)
def replace_child( to_replace, replacement )
ind = @children.index( to_replace )
to_replace.parent = nil
to_replace.remove
@children[ind] = replacement
replacement.parent = self
end
end
end
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