sccd/python_sccd_compiler/sccd_constructs.py

import abc
import re
import xml.etree.ElementTree as ET
import os.path
from utils import Logger
from visitor import Visitable
from compiler_exceptions import CompilerException, TransitionException, UnprocessedException
from lexer import Lexer, Token, TokenType

# http://docs.python.org/2/library/xml.etree.elementtree.html

# list of reserved words
reserved = ["__init__", "__del__", "init", "transition", "microstep", "step", "inState", "event", "addEvent", 
            "broadcast", "getEarliestEvent", "__str__", "controller", 
            "current_state", "timers", "eventQueue", "Controller", "state_changed", "history_state",
            "root", "narrowcast", "object_manager", "update"]

SELF_REFERENCE_SEQ = 'SELF'
INSTATE_SEQ = 'INSTATE'

##################################

class StateReference(Visitable):
    def __init__(self, input_string):
        self.path_string = input_string
        self.target_nodes = None #calculated in state linker
        
    def getNodes(self):
        #if no target nodes are set, it means that the visitor corresponding for that hasn't visited yet
        if self.target_nodes is None:
            raise UnprocessedException("State reference not resolved yet.")
        return self.target_nodes
   
##################################
class ExpressionPart(Visitable):
    __metaclass__  = abc.ABCMeta
    
class ExpressionPartString(ExpressionPart):
    def __init__(self, string):
        self.string = string
    
class SelfReference(ExpressionPart):        
    pass
    
class InStateCall(ExpressionPart):
    def __init__(self, state_strings):
        self.state_strings = state_strings
        self.targets = [StateReference(state_string) for state_string in state_strings]

##################################

    
class Expression(Visitable):
    lexer = Lexer(False, True)
    
    def __init__(self, input):
        if not input :
            raise CompilerException("Empty Expression.")
        self.parse(input)
        
    def parse(self, input, dont_parse = []):
        self.expression_parts = []
        self.lexer.input(input)
        processed_bare_expression = ""
        
        for token in self.lexer.tokens() :
            created_object = None
            
            if token.type == TokenType.WORD :
                if token.val in dont_parse :
                    raise CompilerException("Macro \"" + token.val + "\" not allowed here.")
                elif token.val == SELF_REFERENCE_SEQ :
                    created_object = SelfReference()
                elif token.val == INSTATE_SEQ :
                    created_object = self.parseInStateCall()
                    if created_object is None :
                        raise CompilerException("Illegal use of \"" + INSTATE_SEQ + "\" macro.")
                    
            if created_object is None:
                processed_bare_expression += token.val
            else :    
                if processed_bare_expression != "" :
                    self.expression_parts.append(ExpressionPartString(processed_bare_expression))
                    processed_bare_expression = ""
                self.expression_parts.append(created_object)  
        
        #Process part of input after the last created macro object
        if processed_bare_expression != "" :
            self.expression_parts.append(ExpressionPartString(processed_bare_expression))
            
    def parseInStateCall(self):
        token = self.lexer.nextToken()
        if token is None or token.type != TokenType.LBRACKET :
            return None
        token = self.lexer.nextToken()
        state_strings = []
        while True:
            if token is None or token.type != TokenType.QUOTED :
                return None
            else :
                state_strings.append(token.val[1:-1])
            token = self.lexer.nextToken()
            if token.type == TokenType.COMMA :
                self.lexer.skipWhiteSpace()
                token = self.lexer.nextToken()
            else:
                break
        if token is None or token.type != TokenType.RBRACKET :
            return None
        else :
            return InStateCall(state_strings)

class LValue(Expression):
    def __init__(self, input):
        if not input :
            raise CompilerException("Empty LValue.")
        self.parse(input, [INSTATE_SEQ])
        #do some validation, provide parameters to processString to make the function more efficient
     
##################################     
     
class FormalEventParameter(Visitable):
    def __init__(self, name, ptype = ""):
        self.name = name
        self.type = ptype
        
    def getName(self):
        return self.name
    
    def getType(self):
        return self.type
    
##################################
class TriggerEvent:
    def __init__(self, xml_element):
        self.is_uc = False;
        self.is_after = False
        self.after_index = -1
        self.params = []
        
        self.event = xml_element.get("event", "").strip()
        self.after = xml_element.get("after", "").strip()
        self.port = xml_element.get("port", "").strip()
        if not self.event:
            self.event = None
        if not self.after:
            self.after = None
        if not self.port:
            self.port = None
        if self.event and self.after :
            raise CompilerException("Cannot have both the event and after attribute set for a transition.")
        
        if not self.event and self.port:
            raise CompilerException("A transition without event can not have a port.")

        if self.after :
            if self.port :
                raise CompilerException("After event can not have a port.")
            self.is_after = True
            self.after = Expression(self.after)
            return
        elif not self.event :
            self.is_uc = True
            return
            
        self.params = []
        parameters = xml_element.findall('parameter')    
        for p in parameters :
            name = p.get("name","")
            if not name :
                raise CompilerException("Parameter without name detected.")
            self.params.append(FormalEventParameter(name, p.get("type","")))
            
    def getEvent(self):    
        return self.event
    
    def setEvent(self, event):
        self.event = event
    
    def getParameters(self):    
        return self.params
    
    def getPort(self):
        return self.port
        
    def isUC(self):
        return self.is_uc;
    
    def isAfter(self):
        return self.is_after
    
    def getAfterIndex(self):
        return self.after_index
    
    def setAfterIndex(self, after):
        self.after_index = after
        

##################################

class SubAction(Visitable):
    __metaclass__  = abc.ABCMeta
    
    @abc.abstractmethod
    def check(self):
        pass
    
    @classmethod
    def create(cls, xml_element):
        for subcls in cls.__subclasses__():
            tag = xml_element.tag.lower()
            if subcls.check(tag):
                return subcls(xml_element)
        raise CompilerException("Invalid subaction.")
    
##################################
"""
    Is a possible subaction; generates an event.
"""

class RaiseEvent(SubAction):
    tag = "raise"
    LOCAL_SCOPE = 1
    BROAD_SCOPE = 2
    OUTPUT_SCOPE = 3
    NARROW_SCOPE = 4
    CD_SCOPE = 5
    
    
    def __init__(self, xml_element):
        self.event = xml_element.get("event","").strip()
        scope_string = xml_element.get("scope","").strip().lower()
        self.target = xml_element.get("target","").strip()
        self.port = xml_element.get("port","").strip()
        
        if scope_string == "local" :
            self.scope = self.LOCAL_SCOPE
        elif scope_string == "broad" :
            self.scope = self.BROAD_SCOPE
        elif scope_string == "output" :
            self.scope = self.OUTPUT_SCOPE
        elif scope_string == "narrow" :
            self.scope = self.NARROW_SCOPE
        elif scope_string == "cd" :
            self.scope = self.CD_SCOPE
        elif scope_string == "" :
            #Calculate scope depending on present attributes
            if self.target and self.port :
                raise CompilerException("Both target and port attribute detected without a scope defined.")
            elif self.port :
                self.scope = self.OUTPUT_SCOPE
            elif self.target :
                self.scope = self.NARROW_SCOPE
            else :
                self.scope = self.LOCAL_SCOPE  
            
        else :
            raise CompilerException("Illegal scope attribute; needs to be one of the following : local, broad, narrow, output, cd or nothing.");  
                
        if self.scope == self.LOCAL_SCOPE or self.scope == self.BROAD_SCOPE or self.scope == self.CD_SCOPE:
            if self.target :
                Logger.showWarning("Raise event target detected, not matching with scope. Ignored.")
                self.target = ""
            if self.port :
                Logger.showWarning("Raise event port detected, not matching with scope. Ignored.")
                self.port = ""
        if self.scope == self.NARROW_SCOPE and self.port :
            Logger.showWarning("Raise event port detected, not matching with scope. Ignored.")
            self.port = ""
        if self.scope == self.OUTPUT_SCOPE and self.target :
            Logger.showWarning("Raise event target detected, not matching with scope. Ignored.")
            self.target = ""
                
        self.params = []
        parameters = xml_element.findall('parameter')    
        for p in parameters :
            value = p.get("expr","")
            if not value :
                raise CompilerException("Parameter without value detected.")
            self.params.append(Expression(value))
    
    @staticmethod
    def check(tag):
        return tag == RaiseEvent.tag
    
    def getPort(self):
        return self.port
            
    def isLocal(self):
        return self.scope == self.LOCAL_SCOPE
    
    def isNarrow(self):
        return self.scope == self.NARROW_SCOPE
    
    def isBroad(self):
        return self.scope == self.BROAD_SCOPE
    
    def isOutput(self):
        return self.scope == self.OUTPUT_SCOPE
    
    def isCD(self):
        return self.scope == self.CD_SCOPE
    
    def getTarget(self):
        return self.target
    
    def getEventName(self):
        return self.event
    
    def getParameters(self):    
        return self.params
    
    def getScope(self):
        return self.scope
            
class Script(SubAction):
    tag = "script"
    def __init__(self, xml_element):
        self.code = xml_element.text if xml_element.text else ""
        
    @staticmethod
    def check(tag):
        return tag == Script.tag
            
class Log(SubAction):
    tag = "log"
    def __init__(self, xml_element):
        self.message = xml_element.text.strip()
        
    @staticmethod
    def check(tag):
        return tag == Log.tag

class Assign(SubAction):
    tag = "assign"
    def __init__(self, xml_element):
        self.lvalue = LValue(xml_element.get("ident",""))
        self.expression = Expression(xml_element.get("expr",""))
    
    @staticmethod   
    def check(tag):
        return tag == Assign.tag
  
##################################

"""
    Exists out of multiple subactions
"""
class Action(Visitable):
    def __init__(self, xml_element):
        self.sub_actions = []
        for subaction in list(xml_element) :
            if subaction.tag not in ["parameter"] :      
                self.sub_actions.append(SubAction.create(subaction))
            
    def accept(self, visitor):
        for subaction in self.sub_actions :
            subaction.accept(visitor)
        
##################################

class StateChartTransition(Visitable):
    def __init__(self,xml_element,parent):
        self.xml = xml_element
        self.parent_node = parent
        self.trigger = TriggerEvent(self.xml)
        guard_string = self.xml.get("cond","").strip()
        if guard_string != "" : 
            self.guard = Expression(guard_string)
        else :
            self.guard = None
        self.target_string = self.xml.get("target","").strip()
        if self.target_string == "" :
            raise CompilerException("Transition from <" + self.parent_node.full_name + "> has empty target.")
        self.target = StateReference(self.target_string)
        
        self.action = Action(self.xml)
        
        self.enter_nodes = None # Ordered list of nodes to be entered upon taking the transition, set by the path calculator
        self.exit_nodes = None # Ordered list of nodes to be exited upon taking the transition, set by the path calculator
        self.arena = None # Lowest common Or-state ancestor of source and destination
        
    def getEnterNodes(self):
        if self.enter_nodes is None :
            raise UnprocessedException("Enter path not calculated yet.")
        return self.enter_nodes
    
    def getExitNodes(self):
        if self.exit_nodes is None :
            raise UnprocessedException("Exit path not calculated yet.")
        return self.exit_nodes
        
    def isUCTransition(self):
        """ Returns true iff is an unconditional transition (i.e. no trigger)
        """
        return self.trigger.isUC()
    
    def getParentNode(self):
        return self.parent_node
        
    def getTrigger(self):
        return self.trigger
        
    def getGuard(self):
        return self.guard
        
    def getTargetNodes(self):
        return self.target.getNodes()

    def hasGuard(self):
        return self.guard is not None
    
    def getAction(self):
        return self.action        

##################################  

class EnterExitAction(Visitable):
    def __init__(self, parent_node, xml_element = None):
        self.parent_node = parent_node
        if xml_element is not None:
            self.action = Action(xml_element)
        else :
            self.action = None
        
class EnterAction(EnterExitAction):
    def __init__(self, parent_node, xml_element = None):
        EnterExitAction.__init__(self, parent_node, xml_element)
        
class ExitAction(EnterExitAction):
    def __init__(self, parent_node, xml_element = None):
        EnterExitAction.__init__(self, parent_node, xml_element)
        
##################################  

class StateChartNode(Visitable):
    def __init__(self, statechart, xml_element, parent = None):
        self.statechart = statechart
        self.parent = parent
        self.children = []

        self.is_root = False
        self.is_basic = False
        self.is_composite = False
        self.is_history = False
        self.is_history_deep = False
        self.is_parallel_state = False
        self.save_state_on_exit = False
        self.has_timers = False
        self.initial = None
            
        if xml_element.tag == "scxml" : 
            self.is_root = True
            self.is_composite = True
        elif xml_element.tag == "parallel" : 
            self.is_composite = True
            self.is_parallel_state = True
        elif xml_element.tag == "state" :
            if len(xml_element.findall("state")) > 0 or (len(xml_element.findall("parallel")) > 0) :
                self.is_composite = True
            else :
                self.is_basic = True
            if  self.parent.is_parallel_state :
                if (self.is_basic) :
                    raise CompilerException("Orthogonal nodes (nodes that are immediate children of parallel nodes) can't be basic.")
        elif xml_element.tag == "history" :
            history_type = xml_element.get("type","shallow")
            if history_type == "deep" :
                self.is_history_deep = True
            elif history_type != "shallow" :
                raise CompilerException("Invalid history type.") 
            self.is_history = True            
        else :
            return
                            
        self.resolveName(xml_element)
        #self.parseConflictAttribute(xml_element)
        self.parseEnterActions(xml_element)
        self.parseExitActions(xml_element)
        
        #transitions
        self.transitions = []
        for transition_xml in xml_element.findall("transition"):
            self.transitions.append(StateChartTransition(transition_xml, self))
            
        self.optimizeTransitions()
        self.generateChildren(xml_element)    
        self.calculateDefaults(xml_element)
            
    def resolveName(self, xml):
        if self.is_root :
            self.new_name = ""
            self.new_full_name = ""
            # TODO: remove old names
            self.name = "Root"
            self.full_name = "Root"
        else :
            self.new_name = xml.get("id", "")
            self.new_full_name = self.parent.new_full_name + "/" + self.new_name
            self.friendly_name = self.new_full_name.replace("/", "_")
            self.name = xml.get("id","")
            self.full_name = self.parent.full_name + "_" + self.name
    
    """
    def parseConflictAttribute(self, xml):
        conflict = xml.get("conflict","")
        if conflict == "outer" :
            self.solves_conflict_outer = True
        elif conflict == "inner" :
            self.solves_conflict_outer = False
        else :    
            if not (conflict == "" or conflict == "inherit") :
                raise CompilerException("Unknown conflict attribute for " + self.full_name + ".")
            #Do our default inherit action
            if self.is_root or self.parent.solves_conflict_outer: 
                self.solves_conflict_outer = True
            else :
                self.solves_conflict_outer = False
    """
                
    def parseEnterActions(self, xml):
        on_entries = xml.findall("onentry")
        if on_entries :
            if len(on_entries) > 1:
                raise CompilerException("Multiple <onentry> tags detected for "+ self.full_name + ", only 1 allowed.")
            self.enter_action = EnterAction(self, on_entries[0])
        else :
            self.enter_action = EnterAction(self)
            
    def parseExitActions(self, xml):
        on_exits = xml.findall("onexit")
        if on_exits :
            if len(on_exits) > 1:
                raise CompilerException("Multiple <onexit> tags detected for "+ self.full_name + ", only 1 allowed.")
            self.exit_action = ExitAction(self, on_exits[0])    
        else :
            self.exit_action = ExitAction(self)
            
    def optimizeTransitions(self):
        """If a transition with no trigger and no guard is found then it is considered as the only transition.
        Otherwise the list is ordered by placing transitions having guards only first."""
        onlyguards = []
        withtriggers = []
        optimized = []
        for transition in self.transitions:
            if transition.isUCTransition():
                if not transition.hasGuard():
                    if optimized :
                        raise TransitionException("More than one transition found at a single node, that has no trigger and no guard.")
                    optimized.append(transition)
                else:
                    onlyguards.append(transition)
            else:
                withtriggers.append(transition)
                if transition.trigger.isAfter():
                    self.has_timers = True
        if not optimized :        
            optimized = onlyguards + withtriggers
        self.transitions = optimized
    
    def generateChildren(self, xml):
        children_names = []
        for child_xml in list(xml) :
            child = StateChartNode(self.statechart, child_xml, self)
            if not (child.is_composite or child.is_basic or child.is_history) :
                continue
            self.children.append(child)
            
            #Check if the name of the child is valid
            child_name = child.name
            if child_name == "" :
                raise CompilerException("Found state with no id")
            if child_name in children_names :
                raise CompilerException("Found 2 equivalent id's : " + child_name + ".")
            children_names.append(child_name)
            
    def calculateDefaults(self, xml):
        initial_state = xml.get("initial","")
        
        if self.is_parallel_state :
            self.defaults = [child for child in self.children if not child.is_history]
            if initial_state != "" : 
                raise CompilerException("Component <" + self.full_name + ">  contains an initial state while being parallel.")    
        elif initial_state == "" :
            if self.is_basic or self.is_history:
                pass
            elif len(self.children) == 1 :
                self.defaults = self.children
                self.initial = self.children[0].new_full_name
            else :
                raise CompilerException("Component <" + self.full_name + "> contains no default state.") 
        else :
            if self.is_basic :
                raise CompilerException("Component <" + self.full_name + "> contains a default state while being a basic state.")
            self.defaults = []
            for child in self.children :
                if child.name == initial_state :
                    self.defaults.append(child)
                    self.initial = child.new_full_name
            if len(self.defaults) < 1 :
                raise CompilerException("Initial state '"+ initial_state + "' referred to, is missing in " + self.full_name)
            elif len(self.defaults) > 1 :
                raise CompilerException("Multiple states with the name '" + initial_state + " found in " + self.full_name + " which is referred to as initial state.")
    
    def getAncestors(self):
        """ Returns a list representing the containment hierarchy of node.
            node is always the first element, and its outermost parent is the last.
        """
        current = self
        while not current.is_root :
            current = current.parent
            yield current
    
    def isDescendantOf(self, anc):
        current = self
        while not current.is_root :
            current = current.parent
            if current == anc :
                return True
        return False
        
    def isDescendantOrAncestorOf(self, node):
        return self.isDescendantOf(node) or node.isDescendantOf(self)
  
        
##################################

class StateChart(Visitable):

    def __init__(self, class_obj, statechart_xml):
        """ Gives the module information on the statechart by listing its basic, orthogonal,
            composite and history states as well as mapping triggers to names making the
            appropriate conversion from AFTER() triggers to event names
        """
        
        self.class_obj = class_obj
        self.root = StateChartNode(self, statechart_xml); #creates the whole statechart structure recursively

        self.states = []
        self.basics = []
        self.composites = []
        self.histories = []
        self.nr_of_after_transitions = 0

        def getSemanticOption(name, allowed_values, default_value):
            result = statechart_xml.get(name, default_value)
            if result not in allowed_values:
                raise CompilerException("Illegal value for semantic option " + name + ": '" + result + "'. Allowed values are ['" + "', '".join(allowed_values) + "'], default value is '" + default_value + "'.")
            return result

        self.big_step_maximality = getSemanticOption("big_step_maximality", ["take_one", "take_many"], "take_many")
        self.internal_event_lifeline = getSemanticOption("internal_event_lifeline", ["next_small_step", "next_combo_step", "queue"], "queue")
        self.input_event_lifeline = getSemanticOption("input_event_lifeline", ["first_small_step", "first_combo_step", "whole"], "first_combo_step")
        self.priority = getSemanticOption("priority", ["source_parent", "source_child"], "source_parent")
        self.concurrency = getSemanticOption("concurrency", ["single", "many"], "single")

        if self.internal_event_lifeline == "next_combo_step":
            if self.big_step_maximality == "take_one":
                Logger.showWarning("Using 'Next Combo Step' internal event lifeline semantics and 'Take One' big step maximality semantics simultaneously doesn't make sense.")

        self.extractFromHierarchy(self.root) #recursively extracts the basics, composites, histories and nr_of_after_transitions
            
        # Calculate the history that needs to be taken care of.
        self.shallow_history_parents = []
        self.deep_history_parents = []
        self.combined_history_parents = [] #All nodes that need state saved on leaving
        for node in self.histories:
            self.calculateHistory(node.parent, node.is_history_deep)
            
    def extractFromHierarchy(self, node):
        # For each AFTER event, give it a name so that it can be triggered.
        for transition in node.transitions:
            trigger = transition.trigger
            if trigger.isAfter() :
                trigger.setAfterIndex(self.nr_of_after_transitions)
                value = "_" + str(trigger.getAfterIndex()) + "after"
                trigger.setEvent(value)
                self.nr_of_after_transitions += 1
                
        self.states.append(node)
        if node.is_basic : 
            self.basics.append(node)
        elif node.is_composite : 
            self.composites.append(node)
        elif node.is_history : 
            self.histories.append(node)
            
        for child in node.children :
            self.extractFromHierarchy(child)

    def calculateHistory(self, parent, is_deep):
        """ Figures out which components need to be kept track of for history.
        """
        if parent == self.root:
            raise CompilerException("Root component cannot contain a history state.")
        if parent not in self.combined_history_parents:
            self.combined_history_parents.append(parent)
            parent.save_state_on_exit = True
        if is_deep :
            if parent not in self.deep_history_parents:
                self.deep_history_parents.append(parent)
        else :
            if parent not in self.shallow_history_parents:
                self.shallow_history_parents.append(parent)
        if parent.is_parallel_state or is_deep :
            for i in parent.children:
                if i.is_composite :
                    self.calculateHistory(i, is_deep)
    
###################################

class Association(Visitable):
    def __init__(self, to_class, min_card, max_card, name):
        self.min = min_card
        self.max = max_card #N is represented as -1
        self.to_class = to_class
        self.name = name
        
###################################
class FormalParameter(Visitable):
    def __init__(self, param_ident, param_type, default = None):
        self.param_type = param_type
        self.identifier = param_ident
        self.default = default  
            
    def getType(self):
        return self.param_type
            
    def getIdent(self):
        return self.identifier
    
    def hasDefault(self):
        return self.default is not None
    
    def getDefault(self):
        return self.default
    
#slight hack because of lacking multiple constructors
class XMLFormalParameter(FormalParameter):
    def __init__(self, xml):
        self.param_type = xml.get("type", "")
        self.identifier = xml.get("name","")
        self.default = xml.get("default",None)
    
###################################
class Method(Visitable):
    def __init__(self, xml, parent_class):
        self.name = xml.get("name", "")
        self.access = xml.get("access", "public")
        parameters = xml.findall("parameter")
        self.parameters = []
        for p in parameters:
            self.parameters.append(XMLFormalParameter(p))
        bodies = xml.findall("body")
        if len(bodies) > 1 : 
            raise CompilerException("Method can have at most one body.")
        elif len(bodies) == 1:
            self.body = bodies[0].text
        else:
            self.body = ""
        self.parent_class = parent_class
        self.return_type = xml.get('type',"")
        self.is_abstract = xml.get('abstract', False)
        
    def getParams(self):
        return self.parameters

    def isAbstract(self):
        return self.is_abstract
        
###################################        
class Constructor(Method):
    def __init__(self, xml, parent_class):
        self.super_class_parameters = {};
        if xml is None :
            self.body = ""
            self.name = ""
            self.access = "public"            
            self.parent_class = parent_class
            self.return_type = ""
            self.parameters = []
        else :
            Method.__init__(self, xml, parent_class)      
            super_class_parameters = xml.findall("super")
            for s in super_class_parameters:
                class_name = s.get("class")
                self.super_class_parameters[class_name] = []
                params = s.findall("parameter")
                for p in params:
                    self.super_class_parameters[class_name].append(p.get("expr"))
        
class Destructor(Method):
    def __init__(self, xml, parent_class):
        if xml is None :
            self.body = ""
            self.name = ""
            self.access = "public"            
            self.parent_class = parent_class
            self.return_type = ""
            self.parameters = []
        else :
            Method.__init__(self, xml, parent_class)
        
###################################         
class Attribute(Visitable):
    def __init__(self, xml):
        self.name = xml.get('name',"")
        self.type = xml.get('type',"")
        self.init_value = xml.get("init-value", None)
        
    def getIdent(self):
        return self.name
    
    def getType(self):
        return self.type
    
    def getInit(self):
        return self.init_value
        
###################################

class Class(Visitable):
    def __init__(self, xml, class_diagram):

        self.xml = xml
        self.class_diagram = class_diagram
        self.name = xml.get("name", "")
        self.abstract_method_names = [] # this value will be written to by super_class_linker
        
        self.constructors = []
        self.destructors = []
        self.methods = []
        self.statechart = None

        self.inports = []
        self.outports = []
        self.attributes = []
        self.associations = []
        self.super_classes = []
        self.super_class_objs = {} # maps super class names to super class objects
        
        self.process()
        
    def getName(self):
        return self.name

    def isAbstract(self):
        return len(self.abstract_method_names) > 0
        
    def processMethod(self, method_xml) :
        name = method_xml.get("name", "")
        if name == self.name :
            self.constructors.append(Constructor(method_xml, self))
        elif name == '~' + self.name:
            self.destructors.append(Destructor(method_xml, self))
        else :
            if name in reserved:
                raise CompilerException("Reserved word \"" + name + "\" used as method in class <" + self.name + ">.")
            new_method = Method(method_xml, self)
            self.methods.append(new_method)

    def processAttribute(self, attribute_xml):
        attribute = Attribute(attribute_xml)
        if attribute.name in reserved:
            raise CompilerException("Reserved word \"" + attribute.name + "\" used as variable in class <" + self.name + ">.")

        self.attributes.append(attribute)
    
    def processInheritances(self, inheritances):
        # process each inheritance, stores a dict with each subclass as the key
        # and a list of tuples (superclass, priority) as the value. The priority
        # tells us which class to inherit from first for multiple inheritance. Gives
        # a WARNING with a given inheritance order if two priorities are the same

        for i in inheritances :
            self.super_classes.append((i.get("class",""),i.get("priority",1)))

        self.super_classes.sort(lambda a, b: cmp(b[1], a[1])) # sort from high priority to low priority
        priorityChecker = {}
        for super_class, priority in self.super_classes:
            if priority in priorityChecker:
                checkIt = priorityChecker[priority]
            else:
                checkIt = []
            if super_class not in checkIt:
                checkIt.append(super_class)
            priorityChecker[priority] = checkIt
        for priority, checkIt in priorityChecker.iteritems():
            if len(checkIt) > 1:
                Logger.showWarning("Class <" + self.name + "> inherits from classes <" + ", ".join(checkIt) + "> with same priority <" + str(priority) + ">. Document inheritance order is used.")

        self.super_classes = [entry[0] for entry in self.super_classes]
        
    def processAssociations(self, associations):
        for a in associations :
            class_name = a.get("class","")
            if not class_name :
                raise CompilerException("Faulty association.")
            card_min_string = a.get("min","0")
            try :
                card_min = int(card_min_string)
                if card_min < 0 :
                    raise ValueError()
            except ValueError :
                raise CompilerException("Faulty card-min value in association.")
            card_max_string = a.get("max","N")
            if card_max_string == "N" :
                card_max = -1
            else :
                try :
                    card_max = int(card_max_string)
                    if card_max < card_min :
                        raise ValueError()
                except ValueError :
                    raise CompilerException("Faulty card-max value in association.") 
            
            association_name = a.get("name","")
            if not association_name :
                raise CompilerException("Faulty association. No name.")
            if association_name in reserved : 
                raise CompilerException("Reserved word \"" + association_name + "\" used as association name in class <" + self.name + ">.")
            self.associations.append(
                Association(class_name, card_min, card_max, association_name)
            )

    

    def process(self):
        inports = self.xml.findall("inport")
        for i in inports:
            name = i.get("name")
            if name in self.inports:
                raise CompilerException("Found 2 inports with the same name : " + name + ".")
            self.inports.append(name)

        outports = self.xml.findall("outport")
        for i in outports:
            name = i.get("name")
            if name in self.outports:
                raise CompilerException("Found 2 outports with the same name : " + name + ".")
            self.outports.append(name)

        associations = []
        inheritances = []
        relationships = self.xml.findall("relationships")
        for relationship_wrapper in relationships :
            associations.extend(relationship_wrapper.findall("association"))
            inheritances.extend(relationship_wrapper.findall("inheritance"))
            
        self.processAssociations(associations)
        self.processInheritances(inheritances)

        attributes = self.xml.findall("attribute")
        for a in attributes:
            self.processAttribute(a)

        methods = self.xml.findall("method")
        for m in methods:
            self.processMethod(m)

        constructors = self.xml.findall("constructor")
        for c in constructors:
            self.constructors.append(Constructor(c, self))

        destructors = self.xml.findall("destructor")
        for d in destructors:
            self.destructors.append(Destructor(d, self))
        
        if len(self.constructors) > 1 :
            raise CompilerException("Multiple constructors no longer supported!")

        if len(self.destructors) > 1 :
            raise CompilerException("Multiple destructors defined for class <" + self.name + ">.")

        if len(self.constructors) < 1 :
            # add a default constructor
            self.constructors.append(Constructor(None,self))

        if len(self.destructors) < 1 :
            # add a default destructor
            self.destructors.append(Destructor(None,self))

        statecharts = self.xml.findall("scxml")
        if len(statecharts) > 1 :
            raise CompilerException("Multiple statecharts found in class <" + self.name + ">.")
        if len(statecharts) == 1 :
            self.statechart = StateChart(self, statecharts[0])
            
###################################
class ClassDiagram(Visitable):
    def __init__(self, input_file):
        diagram_dir = os.path.dirname(input_file)
        tree = ET.parse(input_file)
        self.root = tree.getroot()
        self.name = self.root.get("name", "")
        self.author = self.root.get("author", "")
        descriptions = self.root.findall("description")
        self.language = self.root.get("language", "")
        if descriptions : 
            self.description = descriptions[0].text
        else :
            self.description = ""

        xml_classes = self.root.findall("class")
        # make sure at least one class is given
        if not xml_classes :
            raise CompilerException("Found no classes to compile.")

        # check if class diagram is valid
        # unique class names
        self.class_names = []
        substituted_xml_classes = []
        for xml_class in xml_classes :
            class_src = xml_class.get("src", "")
            class_default = xml_class.get("default", "")
            if class_src != "":
                if not os.path.isabs(class_src):
                    class_src = os.path.join(diagram_dir, class_src)
                substituted_xml_class = ET.parse(class_src).getroot()
            else:
                substituted_xml_class = xml_class
            substituted_xml_class.is_default = (class_default.lower() == "true")
            name = substituted_xml_class.get("name", "")
            if name == "" :
                raise CompilerException("Missing or emtpy class name.")
            if name in self.class_names :
                raise CompilerException("Found 2 classes with the same name : " + name + ".")
            self.class_names.append(name)
            substituted_xml_classes.append(substituted_xml_class)
    
        # process in and output ports
        inports = self.root.findall("inport")
        names = []
        for xml_inport in inports :
            name = xml_inport.get("name", "")
            if name in names :
                raise CompilerException("Found 2 INPorts with the same name : " + name + ".")
            names.append(name)
        self.inports = names
        
        outports = self.root.findall("outport")
        names = []
        for xml_outport in outports :
            name = xml_outport.get("name", "")
            if name in names :
                raise CompilerException("Found 2 OUTPorts with the same name : " + name + ".")
            names.append(name)
        self.outports = names
            
        
        # any inital import code that has to come at the top of the generate file
        tops = self.root.findall("top")
        self.includes = []
        if len(tops) == 1 :
            self.top = tops[0].text
        elif len(tops) > 1 : 
            raise CompilerException("Class diagram can only have one <top> element.")
        else :
            self.top = ""
        
        # process each class in diagram
        self.classes = []
        default_classes = []
    
        for xml_class in substituted_xml_classes:
            processed_class = None
            try :
                processed_class = Class(xml_class, self)
            except CompilerException as e :
                e.message = "Class <" + xml_class.get("name", "") + "> failed compilation. " + e.message
                raise e
    
            # let user know this class was successfully loaded
            Logger.showInfo("Class <" + processed_class.name + "> has been successfully loaded.")
            self.classes.append(processed_class)
            if xml_class.is_default :
                default_classes.append(processed_class)
            
        if not default_classes or len(default_classes) > 1:
            if len(self.classes) == 1 :
                Logger.showInfo("Only one class given. Using <" + self.classes[0].getName() + "> as the default class.")
                default_classes.append(self.classes[0])
            else :
                raise CompilerException("Provide one and only one default class to instantiate on start up.")
        self.default_class = default_classes[0]

        # check if there's a test
        self.test = None
        test_nodes = self.root.findall("test")
        if test_nodes:
            test_node = test_nodes[0]

            input_nodes = test_node.findall("input")
            if input_nodes:
                input_node = input_nodes[0]
                test_input = DiagramTestInput(input_node)
            else:
                test_input = None

            expected_nodes = test_node.findall("expected")
            if expected_nodes:
                expected_node = expected_nodes[0]
                test_expected = DiagramTestExpected(expected_node)
            else:
                test_expected = None

            self.test = DiagramTest(test_input, test_expected)


class DiagramTest(Visitable):
    def __init__(self, i, expected):
        self.input = i
        self.expected = expected

class DiagramTestEvent(Visitable):
    def __init__(self, xml):
        self.name = xml.get("name")
        self.port = xml.get("port")
        self.parameters = []
        parameter_nodes = xml.findall("parameter")
        for parameter_node in parameter_nodes:
            val = parameter_node.get("value")
            expr = parameter_node.get("expr")
            if val:
                self.parameters.append(val) # expected events use 'val'
            elif expr:
                self.parameters.append(expr) # input events use 'expr'
            else:
                raise CompilerException("Parameter has no value/expr.")

class DiagramTestInputEvent(DiagramTestEvent):
    def __init__(self, xml):
        DiagramTestEvent.__init__(self, xml)
        self.time = xml.get("time")

class DiagramTestInput(Visitable):
    def __init__(self, xml):
        self.input_events = []
        event_nodes = xml.findall("event")
        for event_node in event_nodes:
            e = DiagramTestInputEvent(event_node)
            self.input_events.append(e)

class DiagramTestExpectedSlot(Visitable):
    def __init__(self, xml):
        self.expected_events = []
        event_nodes = xml.findall("event")
        for event_node in event_nodes:
            e = DiagramTestEvent(event_node)
            self.expected_events.append(e)

class DiagramTestExpected(Visitable):
    def __init__(self, xml):
        self.slots = []
        slot_nodes = xml.findall("slot")
        for slot_node in slot_nodes:
            s = DiagramTestExpectedSlot(slot_node)
            self.slots.append(s)