Class: OM::XML::DynamicNode

Inherits:
Object
  • Object
show all
Defined in:
lib/om/xml/dynamic_node.rb

Overview

Provides a natural syntax for using OM Terminologies to access values from xml Documents

Note: All of these examples assume that @article is an instance of OM::Samples::ModsArticle. Look at that file to see the Terminology.

Examples:

Return an array of the value(s) “start page” node(s) from the second issue node within the first journal node

# Using DynamicNode syntax:
@article.journal(0).issue(1).pages.start
# Other ways to perform this query:
@article.find_by_terms({:journal => 0}, {:issue => 1}, :pages, :start)
@article.ng_xml.xpath("//oxns:relatedItem[@type=\"host\"]/oxns:part[2]/extent[@unit="pages"]", {"oxns"=>"http://www.loc.gov/mods/v3"})

Return an NodeSet of the _first titles_ of all journal nodes

# Using DynamicNode syntax:
@article.journal.title(1)
# Other ways to perform this query:
@article.find_by_terms(:journal, {:title => 1})
@article.ng_xml.xpath("//oxns:relatedItem[@type=\"host\"]/oxns:titleInfo/oxns:title[1]", {"oxns"=>"http://www.loc.gov/mods/v3"})

Find all of the titles from all journals & return the first title Node from that NodeSet

# Using DynamicNode syntax:
@article.journal.title[1]
# Other ways to perform this query:
@article.find_by_terms(:journal, :title)[1]
@article.ng_xml.xpath("//oxns:relatedItem[@type=\"host\"]/oxns:titleInfo/oxns:title", {"oxns"=>"http://www.loc.gov/mods/v3"})[1]

Defined Under Namespace

Classes: AddressedNode

Instance Attribute Summary (collapse)

Instance Method Summary (collapse)

Constructor Details

- (DynamicNode) initialize(key, index, document, term, parent = nil)

TODO a real term object in here would make it easier to lookup



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# File 'lib/om/xml/dynamic_node.rb', line 33

def initialize(key, index, document, term, parent=nil)  ##TODO a real term object in here would make it easier to lookup
  self.key = key
  self.index = index
  @document = document
  self.term = term
  self.parent = parent
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

- (Object) method_missing(name, *args, &block)



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# File 'lib/om/xml/dynamic_node.rb', line 41

def method_missing (name, *args, &block)
  if /=$/.match(name.to_s)
    new_update_node(name, args)
  elsif args.length > 1
    new_update_node_with_index(name, args)
  else
    child =  term_child_by_name(term.nil? ? parent.term : term, name)
    if child
      OM::XML::DynamicNode.new(name, args.first, @document, child, self)
    else 
      val.send(name, *args, &block)
    end
  end
end

Instance Attribute Details

- (Object) addressed_node

Returns the value of attribute addressed_node



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# File 'lib/om/xml/dynamic_node.rb', line 32

def addressed_node
  @addressed_node
end

- (Object) index

Returns the value of attribute index



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# File 'lib/om/xml/dynamic_node.rb', line 32

def index
  @index
end

- (Object) key

Returns the value of attribute key



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# File 'lib/om/xml/dynamic_node.rb', line 32

def key
  @key
end

- (Object) parent

Returns the value of attribute parent



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# File 'lib/om/xml/dynamic_node.rb', line 32

def parent
  @parent
end

- (Object) term

Returns the value of attribute term



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# File 'lib/om/xml/dynamic_node.rb', line 32

def term
  @term
end

Instance Method Details

- (Object) ==(other)



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# File 'lib/om/xml/dynamic_node.rb', line 121

def ==(other)
  other == val
end

- (Object) delete



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# File 'lib/om/xml/dynamic_node.rb', line 113

def delete
  nodeset.delete
end

- (Boolean) eql?(other)

Returns:

  • (Boolean)


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# File 'lib/om/xml/dynamic_node.rb', line 125

def eql?(other)
  self == other
end

- (Object) inspect



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# File 'lib/om/xml/dynamic_node.rb', line 117

def inspect
  val.inspect
end

- (Object) new_update_node(name, args)



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# File 'lib/om/xml/dynamic_node.rb', line 56

def new_update_node(name, args)
  modified_name = name.to_s.chop.to_sym
  child = term.retrieve_term(modified_name)
  node = OM::XML::DynamicNode.new(modified_name, nil, @document, child, self)
  node.val=args
end

- (Object) new_update_node_with_index(name, args)



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# File 'lib/om/xml/dynamic_node.rb', line 63

def new_update_node_with_index(name, args)
  index = args.shift
  child = term.retrieve_term(name)
  node = OM::XML::DynamicNode.new(name, index, @document, child, self)
  node.val=args
end

- (Object) nodeset



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# File 'lib/om/xml/dynamic_node.rb', line 107

def nodeset
  query = xpath
  trim_text = !query.index("text()").nil?
  return @document.find_by_xpath(query)
end

- (Object) retrieve_addressed_node

This is very similar to Terminology#retrieve_term, however it expands proxy paths out into their cannonical paths



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# File 'lib/om/xml/dynamic_node.rb', line 159

def retrieve_addressed_node()
   chain = []
      
   if parent
     chain += parent.retrieve_addressed_node()
   end
   if (self.index)
     ### This is an index
     node = AddressedNode.new(key, term.xpath_relative, self)
     node.xpath = OM::XML::TermXpathGenerator.add_node_index_predicate(node.xpath, index)
     chain << node
   elsif (term.kind_of? NamedTermProxy)
      proxy = term.proxy_pointer.dup
      first = proxy.shift
      p = @document.class.terminology.retrieve_node(*first)
      chain << AddressedNode.new(p, p.xpath_relative, self)
      while !proxy.empty?
        first = proxy.shift
        p = p.retrieve_term(first)
        chain << AddressedNode.new(p, p.xpath_relative, self)
      end
   else 
     chain << AddressedNode.new(key, term.xpath_relative, self)
   end
   chain
end

- (Object) term_child_by_name(term, name)



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# File 'lib/om/xml/dynamic_node.rb', line 92

def term_child_by_name(term, name)
  if (term.kind_of? NamedTermProxy)
     @document.class.terminology.retrieve_node(*(term.proxy_pointer.dup << name)) 
  else
    term.retrieve_term(name)
  end
end

- (Object) to_pointer



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# File 'lib/om/xml/dynamic_node.rb', line 129

def to_pointer
  if self.index
    parent.nil? ?  [{key => index}] : parent.to_pointer << {key => index}
  else ### A pointer
    parent.nil? ? [key] : parent.to_pointer << key
  end
end

- (Object) val



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# File 'lib/om/xml/dynamic_node.rb', line 100

def val 
  query = xpath
  trim_text = !query.index("text()").nil?
  val = @document.find_by_xpath(query).collect {|node| (trim_text ? node.text.strip : node.text) }
  term.deserialize(val)
end

- (Object) val=(args)



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# File 'lib/om/xml/dynamic_node.rb', line 70

def val=(args)
  @document.ng_xml_will_change!
  new_values = term.sanitize_new_values(args.first)
  existing_nodes = @document.find_by_xpath(xpath)
  if existing_nodes.length > new_values.length
    starting_index = new_values.length + 1
    starting_index.upto(existing_nodes.size).each do |index|
      @document.term_value_delete select: xpath, child_index: index
    end
  end
  new_values.each_with_index do |z, y|
## If we pass something that already has an index on it, we should be able to add it.
    if existing_nodes[y.to_i].nil?
      parent_pointer = parent ? parent.to_pointer : nil
      @document.term_values_append(:parent_select=> parent_pointer,:parent_index=>0,:template=>to_pointer,:values=>z)
    else
      @document.term_value_update(xpath, y.to_i, z)
    end
  end
end

- (Object) xpath



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# File 'lib/om/xml/dynamic_node.rb', line 137

def xpath
  if parent.nil?
    @document.class.terminology.xpath_with_indexes(*(to_pointer << {})) ### last element is always filters
  else
    chain = retrieve_addressed_node( )
    '//' + chain.map { |n| n.xpath}.join('/')
  end
  
end