Added UTA::Models::Transaction.

lib/uta/models/transaction.rb

@@ -0,0 +1,68 @@
+require 'uuid'
+
+module UTA::Models
+  # An instance of <http://uptheasset.org/ontology#Transaction>.
+  #
+  # A transaction is the record of an exchange between two or more accounts in
+  # a journal. Every transaction should have at least two entries (one credit,
+  # one debit).
+  class Transaction
+    include Spira::Resource
+
+    base_uri "this:transactions#"
+    type RDF::UTA.Transaction
+
+    property :id, :predicate => RDF::DC.identifier
+    property :date, :predicate => RDF::DC.date
+    property :label, :predicate => RDF::RDFS.label
+    property :comment, :predicate => RDF::RDFS.comment
+
+    has_many :entries, :predicate => RDF::UTA.entry, :type => :Entry
+
+    # Generate and save a new transaction (with its own UUID).
+    #
+    # @param [Hash] attributes
+    #   An optional hash of attributes to set on the generated transaction.
+    #
+    # @yield [Transaction] The generated transaction (not yet saved).
+    #
+    # @return [Transaction] The saved transaction.
+    #
+    # @example Record a sale
+    #   Transaction.generate do |t|
+    #     t.credit 30, RDF::URI.new("accounts#revenue")
+    #     t.debit  30, RDF::URI.new("accounts#cash")
+    #   end
+    def self.generate(attributes = {})
+      uuid = ::UUID.new.generate
+      transaction = self.for(uuid)
+      transaction.id = RDF::UUID[uuid]
+      transaction.date = Date.today
+      transaction.update(attributes)
+      yield transaction if block_given?
+      transaction.save!
+    end
+
+    # Add a (saved) credit {Entry} to this transaction.
+    #
+    # @param [RDF::Value] amount
+    #   The amount by which to credit.
+    # @param [Account, RDF::URI] account
+    #   The account to credit.
+    # @return [Entry] the created entry.
+    def credit(amount, account)
+      self.entries << Entry.credit(amount, account).save!
+    end
+
+    # Add a (saved) debit {Entry} to this transaction.
+    #
+    # @param [RDF::Value] amount
+    #   The amount by which to debit.
+    # @param [Account, RDF::URI] account
+    #   The account to debit.
+    # @return [Entry] the created entry.
+    def debit(amount, account)
+      self.entries << Entry.debit(amount, account).save!
+    end
+  end
+end