Module: Neo4j::Wrapper::HasN::ClassMethods

Defined in:
lib/neo4j-wrapper/has_n/class_methods.rb

Instance Method Summary collapse

Instance Method Details

#_decl_rels ⇒ Hash

Returns a hash of all relationship and its configuration defined by has_n and has_one.

Returns:

  • (Hash) —

    a hash of all relationship and its configuration defined by has_n and has_one



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# File 'lib/neo4j-wrapper/has_n/class_methods.rb', line 7

def _decl_rels
  @_decl_rels ||= {}
end

#has_n(rel_type) ⇒ Neo4j::Wrapper::HasN::DeclRel

Specifies a relationship between two node classes. Generates assignment and accessor methods for the given relationship. Both incoming and outgoing relationships can be declared, see DeclRel

Examples:

has_n(:files)


class FolderNode
   include Ne4j::NodeMixin
   has_n(:files)
end

folder = FolderNode.new
folder.files << Neo4j::Node.new << Neo4j::Node.new
folder.files.inject {...}

FolderNode.files #=> 'files' the name of the relationship

has_n(x).to(…)


# You can declare which class it has relationship to.
# The generated relationships will be prefixed with the name of that class.
class FolderNode
   include Ne4j::NodeMixin
   has_n(:files).to(File)
   # Same as has_n(:files).to("File")
end

FolderNode.files #=> 'File#files' the name of the relationship

has_n(x).from(class, has_n_name)


# generate accessor method for traversing and adding relationship on incoming nodes.
class FileNode
   include Ne4j::NodeMixin
   has_one(:folder).from(FolderNode.files)
   # or same as
   has_one(:folder).from(FolderNode, :files)
end

Using Cypher

# from FolderNode example above
folder.files.query{ cypher query DSL, see neo4j-core}
folder.files{ } # same as above
folder.files.query(:name => 'file.txt') # a cypher query with WHERE and statements
folder.files(:name => 'file.txt') # same as above
folder.files.query.to_s # the cypher query explained as a String

Returns:



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# File 'lib/neo4j-wrapper/has_n/class_methods.rb', line 68

def has_n(rel_type)
  clazz = self
  module_eval(%Q{
        def #{rel_type}(cypher_hash_query = nil, &cypher_block)
            dsl = _decl_rels_for('#{rel_type}'.to_sym)
            Neo4j::Wrapper::HasN::Nodes.new(self, dsl, cypher_hash_query, &cypher_block)
        end}, __FILE__, __LINE__)


  module_eval(%Q{
        def #{rel_type}_rels
            dsl = _decl_rels_for('#{rel_type}'.to_sym)
            dsl.all_relationships(self)
        end}, __FILE__, __LINE__)

  instance_eval(%Q{
  def #{rel_type}
    _decl_rels[:#{rel_type}].rel_type
  end}, __FILE__, __LINE__)

  _decl_rels[rel_type.to_sym] = DeclRel.new(rel_type, false, clazz)
end

#has_one(rel_type) ⇒ Neo4j::Wrapper::HasN::DeclRel

Specifies a relationship between two node classes. Generates assignment and accessor methods for the given relationship Old relationship is deleted when a new relationship is assigned. Both incoming and outgoing relationships can be declared, see DeclRel

Examples:


class FileNode
   include Ne4j::NodeMixin
   has_one(:folder)
end

file = FileNode.new
file.folder = Neo4j::Node.new
file.folder # => the node above
file.folder_rel # => the relationship object between those nodes

Returns:



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# File 'lib/neo4j-wrapper/has_n/class_methods.rb', line 110

def has_one(rel_type)
  clazz = self
  module_eval(%Q{def #{rel_type}=(value)
          dsl = _decl_rels_for(:#{rel_type})
          rel = dsl.single_relationship(self)
          rel.del unless rel.nil?
          dsl.create_relationship_to(self, value) if value
      end}, __FILE__, __LINE__)

  module_eval(%Q{def #{rel_type}
          dsl = _decl_rels_for('#{rel_type}'.to_sym)
          dsl.single_node(self)
      end}, __FILE__, __LINE__)

  module_eval(%Q{def #{rel_type}_rel
          dsl = _decl_rels_for(:#{rel_type})
          dsl.single_relationship(self)
       end}, __FILE__, __LINE__)

  instance_eval(%Q{
  def #{rel_type}
    _decl_rels[:#{rel_type}].rel_type
  end}, __FILE__, __LINE__)

  _decl_rels[rel_type.to_sym] = DeclRel.new(rel_type, true, clazz)
end

#inherited(klass) ⇒ Object

make sure the inherited classes inherit the _decl_rels hash



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# File 'lib/neo4j-wrapper/has_n/class_methods.rb', line 12

def inherited(klass)
  copy = _decl_rels.clone
  copy.each_pair{|k,v| copy[k] = v.inherit_new}
  klass.instance_variable_set(:@_decl_rels, copy)
  super
end