/
rule_node.rb
216 lines (184 loc) · 6.39 KB
/
rule_node.rb
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module Neo4j
module Rule
# This is the node that has relationships to all nodes of a given class.
# For example if the PersonNode has a rule then it will also have one RuleNode
# from where it will create relationships to each created node of type PersonNode.
# The RuleNode can also be used to hold properties for functions, like sum and count.
#
class RuleNode
include ToJava
attr_reader :rules
attr_reader :model_class
@@rule_nodes = {}
def initialize(clazz)
@model_class = eval("#{clazz}")
@classname = clazz
@rules = []
@rule_node_key = ("rule_" + clazz.to_s).to_sym
@ref_node_key = ("rule_ref_for_" + clazz.to_s).to_sym
end
def to_s
"RuleNode #{@classname}, node #{rule_node} #rules: #{@rules.size}"
end
# returns true if the rule node exist yet in the database
def node_exist?
!ref_node.rel?(@classname)
end
def rule_node
ref_node._java_node.synchronized do
@@rule_nodes[key] ||= find_node || create_node
end
end
def rule_node?(node)
@@rule_nodes[key] == node
end
def key
"#{ref_node}#{@ref_node_key}".to_sym
end
def ref_node
if @model_class.respond_to? :ref_node_for_class
@model_class.ref_node_for_class
else
Neo4j.ref_node
end
end
def create_node
Neo4j::Transaction.run do
node = Neo4j::Node.new
ref_node.create_relationship_to(node, type_to_java(@classname))
node
end
end
def inherit(subclass)
@rules.each do |rule|
subclass.rule rule.rule_name, rule.props, &rule.filter
end
end
def delete_node
if ref_node.rel?(@classname)
ref_node.outgoing(@classname).each { |n| n.del }
end
clear_rule_node
end
def find_node
ref_node.rel?(@classname.to_s) && ref_node._rel(:outgoing, @classname.to_s)._end_node
end
def ref_node_changed?
if ref_node != Thread.current[@ref_node_key]
Thread.current[@ref_node_key] = ref_node
true
else
false
end
end
def clear_rule_node
@@rule_nodes[key] = nil
end
def rule_names
@rules.map { |r| r.rule_name }
end
def find_rule(rule_name)
@rules.find { |rule| rule.rule_name == rule_name }
end
def add_rule(rule)
@rules << rule
end
def remove_rule(rule_name)
r = find_rule(rule_name)
r && @rules.delete(r)
end
# Return a traversal object with methods for each rule and function.
# E.g. Person.all.old or Person.all.sum(:age)
def traversal(rule_name)
# define method on the traversal
traversal = rule_node.outgoing(rule_name)
@rules.each do |rule|
traversal.filter_method(rule.rule_name) do |path|
path.end_node.rel?(rule.rule_name, :incoming)
end
rule.functions && rule.functions.each do |func|
traversal.functions_method(func, self, rule_name)
end
end
traversal
end
def find_function(rule_name, function_name, function_id)
rule = find_rule(rule_name)
rule.find_function(function_name, function_id)
end
def execute_rules(node, *changes)
@rules.each do |rule|
execute_rule(rule, node, *changes)
execute_other_rules(rule, node)
end
end
def execute_other_rules(rule, node)
rule.triggers && rule.triggers.each do |rel_type|
node.incoming(rel_type).each { |n| n.trigger_rules }
end
end
def execute_rule(rule, node, *changes)
if rule.execute_filter(node)
if connected?(rule.rule_name, node)
# it was already connected - the node is in the same rule group but a property has changed
execute_update_functions(rule, *changes)
else
# the node has changed or is in a new rule group
connect(rule.rule_name, node)
execute_add_functions(rule, *changes)
end
else
if break_connection(rule.rule_name, node)
# the node has been removed from a rule group
execute_delete_functions(rule, *changes)
end
end
end
def execute_update_functions(rule, *changes)
if functions = find_functions_for_changes(rule, *changes)
functions && functions.each { |f| f.update(rule.rule_name, rule_node, changes[1], changes[2]) }
end
end
def execute_add_functions(rule, *changes)
if functions = find_functions_for_changes(rule, *changes)
functions && functions.each { |f| f.add(rule.rule_name, rule_node, changes[2]) }
end
end
def execute_delete_functions(rule, *changes)
if functions = find_functions_for_changes(rule, *changes)
functions.each { |f| f.delete(rule.rule_name, rule_node, changes[1]) }
end
end
def find_functions_for_changes(rule, *changes)
!changes.empty? && rule.functions_for(changes[0])
end
# work out if two nodes are connected by a particular relationship
# uses the end_node to start with because it's more likely to have less relationships to go through
# (just the number of superclasses it has really)
def connected?(rule_name, end_node)
end_node.incoming(rule_name).find { |n| n == rule_node }
end
def connect(rule_name, end_node)
rule_node._java_node.createRelationshipTo(end_node._java_node, org.neo4j.graphdb.DynamicRelationshipType.withName(rule_name))
end
# sever a direct one-to-one relationship if it exists
def break_connection(rule_name, end_node)
rel = end_node._rels(:incoming, rule_name).find { |r| r._start_node == rule_node }
rel && rel.del
!rel.nil?
end
def bulk_update?
@rules.size == 1 && @rules.first.bulk_update?
end
def classes_changed(total)
@rules.each do |rule|
if rule.bulk_update?
rule.functions.first.classes_changed(rule.rule_name, rule_node, total)
total.added.each{|node| connect(rule.rule_name, node)}
total.deleted.each{|node| break_connection(rule.rule_name, node)}
end
end
end
end
end
end