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

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

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 31

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

#method_missing(name, *args) ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 39

def method_missing (name, *args)
  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)
    end
  end
end

Instance Attribute Details

#addressed_node ⇒ Object

Returns the value of attribute addressed_node.



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# File 'lib/om/xml/dynamic_node.rb', line 30

def addressed_node
  @addressed_node
end

#index ⇒ Object

Returns the value of attribute index.



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# File 'lib/om/xml/dynamic_node.rb', line 30

def index
  @index
end

#key ⇒ Object

Returns the value of attribute key.



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# File 'lib/om/xml/dynamic_node.rb', line 30

def key
  @key
end

#parent ⇒ Object

Returns the value of attribute parent.



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# File 'lib/om/xml/dynamic_node.rb', line 30

def parent
  @parent
end

#term ⇒ Object

Returns the value of attribute term.



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# File 'lib/om/xml/dynamic_node.rb', line 30

def term
  @term
end

Instance Method Details

#==(other) ⇒ Object 



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

def ==(other)
  val == other
end

#eql?(other) ⇒ Boolean

Returns:

  • (Boolean) 


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

def eql?(other)
  self == other
end

#inspect ⇒ Object 



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

def inspect
  val.inspect
end

#new_update_node(name, args) ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 54

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

#new_update_node_with_index(name, args) ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 61

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

#nodeset ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 111

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

#retrieve_addressed_node ⇒ Object

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

#sanitize_new_values(new_values) ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 83

def sanitize_new_values(new_values)
    # Sanitize new_values to always be a hash with indexes
    case new_values
    when Hash
    when Array
      nv = new_values.dup
      new_values = {}
      nv.each {|v| new_values[nv.index(v).to_s] = v}
    else
      new_values = {"0"=>new_values}
    end
    new_values
end

#term_child_by_name(term, name) ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 97

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

#to_pointer ⇒ Object 



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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

#val ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 105

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

#val=(args) ⇒ Object 



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# File 'lib/om/xml/dynamic_node.rb', line 68

def val=(args)
  new_values = sanitize_new_values(args.first)
  new_values.each do |y,z|   
## If we pass something that already has an index on it, we should be able to add it.
    if @document.find_by_xpath(xpath)[y.to_i].nil? || y.to_i == -1
      @document.term_values_append(:parent_select=> parent.to_pointer,:parent_index=>0,:template=>to_pointer,:values=>z)
    else
      @document.term_value_update(xpath, y.to_i, z)
    end
  end
  if @document.respond_to?(:dirty=)
    @document.dirty = true
  end
end

#xpath ⇒ Object 



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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