smcjavagenerator.java

SMC takes a state machine stored in a .sm file and generates a State pattern in twelve programming l

            // Declare the "ctxt" local variable.
            _source.print("                ");
            _source.print(context);
            _source.println(" ctxt = context.getOwner();");
            _source.println();

            // Generate the actions associated with this code.
            indent2 = _indent;
            _indent = "                ";
            for (SmcAction action: actions)
            {
                action.accept(this);
            }

            _indent = indent2;

            // End the Entry() member function with a return.
            _source.println("                return;");
            _source.println("            }");
        }

        actions = state.getExitActions();
        if (actions != null && actions.size() > 0)
        {
            _source.println();
            _source.print("            protected void Exit(");
            _source.print(context);
            _source.println("Context context)");
            _source.println("            {");

            // Declare the "ctxt" local variable.
            _source.print("                ");
            _source.print(context);
            _source.println(" ctxt = context.getOwner();");
            _source.println();

            // Generate the actions associated with this code.
            indent2 = _indent;
            _indent = "                ";
            for (SmcAction action: actions)
            {
                action.accept(this);
            }

            // End the Exit() member function with a return.
            _source.println("                return;");
            _source.println("            }");
        }

        // Have each transition generate its code.
        _indent = "            ";
        for (SmcTransition transition: state.getTransitions())
        {
            transition.accept(this);
        }

        _source.println();
        _source.println(
            "        //-------------------------------------------------------");
        _source.println("        // Member data.");
        _source.println("        //");

        // If -reflect was specified, then generate the
        // _transitions map.
        if (Smc.isReflection() == true)
        {
            List<SmcTransition> allTransitions =
                map.getFSM().getTransitions();
            List<SmcTransition> stateTransitions =
                state.getTransitions();
            SmcState defaultState = map.getDefaultState();
            List<SmcTransition> defaultTransitions;
            String transName;
            int transDefinition;

            // Initialize the default transition list to all the
            // default state's transitions.
            if (defaultState != null)
            {
                defaultTransitions =
                    defaultState.getTransitions();
            }
            else
            {
                defaultTransitions =
                    new ArrayList<SmcTransition>();
            }

            _source.println();
            _source.println(
                "            //---------------------------------------------------");
            _source.println("            // Statics.");
            _source.println("            //");
            _source.print("            ");
            _source.println("private static Map _transitions;");
            _source.println();

            // Now output the transition collection's
            // initialization.
            _source.println("            static");
            _source.println("            {");
            _source.print("                ");
            _source.println("_transitions = new HashMap();");

            // Now place all transition names and states into the
            // map.
            for (SmcTransition transition: allTransitions)
            {
                transName = transition.getName();

                // If the transition is in this state, then its
                // value is 1.
                if (stateTransitions.contains(
                        transition) == true)
                {
                    transDefinition = 1;
                }
                // If the transition is defined in this map's
                // default state, then the value is 2.
                else if (defaultTransitions.contains(
                             transition) == true)
                {
                    transDefinition = 2;
                }
                // Otherwise the value is 0 - undefined.
                else
                {
                    transDefinition = 0;
                }

                _source.print("                ");
                _source.print("_transitions.put(\"");
                _source.print(transName);
                _source.print("\", new Integer(");
                _source.print(transDefinition);
                _source.println("));");
            }
            _source.println("            }");
        }

        // End of this state class declaration.
        _source.println("        }");

        return;
    } // end of visit(SmcState)

    public void visit(SmcTransition transition)
    {
        SmcState state = transition.getState();
        SmcMap map = state.getMap();
        String context = map.getFSM().getContext();
        String mapName = map.getName();
        String stateName = state.getClassName();
        String transName = transition.getName();
        List<SmcParameter> parameters =
            transition.getParameters();
        List<SmcGuard> guards = transition.getGuards();
        boolean nullCondition = false;
        Iterator<SmcParameter> pit;
        Iterator<SmcGuard> git;
        SmcGuard guard;

        _source.println();
        _source.print(_indent);
        _source.print("protected void ");
        _source.print(transName);
        _source.print("(");
        _source.print(context);
        _source.print("Context context");

        // Add user-defined parameters.
        for (SmcParameter parameter: parameters)
        {
            _source.print(", ");
            parameter.accept(this);
        }
        _source.println(")");

        _source.print(_indent);
        _source.println("{");

        // All transitions have a "ctxt" local variable.
        // 8/14/2003:
        // Do this only if there are any transition actions or
        // guard conditions which reference it.
        if (transition.hasCtxtReference() == true)
        {
            _source.print(_indent);
            _source.print("    ");
            _source.print(context);
            _source.println(" ctxt = context.getOwner();");
        }

        _source.println();

        // Output transition to debug stream.
        if (Smc.isDebug() == true)
        {
            String sep;

            _source.print(_indent);
            _source.println(
                "    if (context.getDebugFlag() == true)");
            _source.print(_indent);
            _source.println("    {");
            _source.print(_indent);
            _source.print("        PrintStream str = ");
            _source.println("context.getDebugStream();");
            _source.println();
            _source.print(_indent);
            _source.print(
                "        str.println(\"TRANSITION   : ");
            _source.print(mapName);
            _source.print('.');
            _source.print(stateName);
            _source.print('.');
            _source.print(transName);

            _source.print('(');
            for (pit = parameters.iterator(), sep = "";
                 pit.hasNext() == true;
                 sep = ", ")
            {
                _source.print(sep);
                (pit.next()).accept(this);
            }
            _source.print(')');

            _source.println("\");");
            _source.print(_indent);
            _source.println("    }");
            _source.println();
        }

        // Loop through the guards and print each one.
        for (git = guards.iterator(),
                 _guardIndex = 0,
                 _guardCount = guards.size();
             git.hasNext() == true;
             ++_guardIndex)
        {
            guard = git.next();

            // Count up the guards with no condition.
            if (guard.getCondition().length() == 0)
            {
                nullCondition = true;
            }

            guard.accept(this);
        }

        // If all guards have a condition, then create a final
        // "else" clause which passes control to the default
        // transition. Pass all arguments into the default
        // transition.
        if (_guardIndex > 0 && nullCondition == false)
        {
            if (_guardCount == 1)
            {
                _source.print(_indent);
                _source.println("    }");
            }

            _source.print(_indent);
            _source.println("    else");
            _source.print(_indent);
            _source.println("    {");

            // Call the super class' transition method using
            // the "super" keyword and not the class name.
            _source.print(_indent);
            _source.print("        super.");
            _source.print(transName);
            _source.print("(context");

            for (SmcParameter param: parameters)
            {
                _source.print(", ");
                _source.print(param.getName());
            }

            _source.println(");");
            _source.print(_indent);
            _source.println("    }");
            _source.println();
        }
        // Need to add a final newline after a multiguard block.
        else if (_guardCount > 1)
        {
            _source.println();
            _source.println();
        }

        _source.print(_indent);
        _source.println("    return;");
        _source.print(_indent);
        _source.println("}");

        return;
    } // end of visit(SmcTransition)

    public void visit(SmcGuard guard)
    {
        SmcTransition transition = guard.getTransition();
        SmcState state = transition.getState();
        SmcMap map = state.getMap();
        String context = map.getFSM().getContext();
        String mapName = map.getName();
        String stateName = state.getClassName();
        int transType = guard.getTransType();
        boolean defaultFlag =
            stateName.equalsIgnoreCase("Default");
        boolean loopbackFlag = false;
        String indent2;
        String indent3;
        String indent4;
        String endStateName = guard.getEndState();
        String fqEndStateName = "";
        String pushStateName = guard.getPushState();
        String condition = guard.getCondition();
        List<SmcAction> actions = guard.getActions();
        boolean hasActions = !(actions.isEmpty());

        // If this guard's end state is not of the form
        // "map::state", then prepend the map name to the
        // state name.
        // DON'T DO THIS IF THIS IS A POP TRANSITION!
        // The "state" is actually a transition name.
        if (transType != Smc.TRANS_POP &&
            endStateName.length () > 0 &&
            endStateName.equals("nil") == false)
        {
            endStateName = scopeStateName(endStateName, mapName);
        }

        // Qualify the state and push state names as well.
        stateName = scopeStateName(stateName, mapName);
        pushStateName = scopeStateName(pushStateName, mapName);

        loopbackFlag =
            isLoopback(transType, stateName, endStateName);

        // The guard code generation is a bit tricky. The first
        // question is how many guards are there? If there are
        // more than one, then we will need to generate the
        // proper "if-then-else" code.
        if (_guardCount > 1)
        {
            indent2 = _indent + "        ";

            // There are multiple guards.
            // Is this the first guard?
            if (_guardIndex == 0 && condition.length() > 0)
            {
                // Yes, this is the first. This means an "if"
                // should be used.
                _source.print(_indent);
                _source.print("    if (");
                _source.print(condition);
                _source.println(")");
                _source.print(_indent);
                _source.println("    {");
            }
            else if (condition.length() > 0)
            {
                // No, this is not the first transition but it
                // does have a condition. Use an "else if".
                _source.println();
                _source.print(_indent);
                _source.print("    else if (");
                _source.print(condition);
                _source.println(")");
                _source.print(_indent);
                _source.println("    {");
            }
            else
            {
                // This is not the first transition and it has
                // no condition.
                _source.println();
                _source.print(_indent);
                _source.println("    else");
                _source.print(_indent);
                _source.println("    {");
            }
        }
        // There is only one guard. Does this guard have a
        // condition?
        else if (condition.length() == 0)
        {
            // No. This is a plain, old. vanilla transition.
            indent2 = _indent + "    ";
        }
        else
        {
            // Yes there is a condition.
            indent2 = _indent + "        ";

            _source.print(_indent);
            _source.print("    if (");
            _source.print(condition);
            _source.println(")");
            _source.print(_indent);
            _source.println("    {");
        }

        // Now that the necessary conditions are in place, it's
        // time to dump out the transition's actions. First, do
        // the proper handling of the state change. If this
        // transition has no actions, then set the end state
        // immediately. Otherwise, unset the current state so
        // that if an action tries to issue a transition, it will
        // fail.
        if (hasActions == false)
        {
            fqEndStateName = endStateName;
        }
        // Save away the current state if this is a loopback
        // transition. Storing current state allows the
        // current state to be cleared before any actions are
        // executed. Remember: actions are not allowed to
        // issue transitions and clearing the current state
        // prevents them from doing do.
        else if (loopbackFlag == true)
        {
            fqEndStateName = "endState";

            _source.print(indent2);
            _source.print(context);
            _source.print("State ");