smccppgenerator.java

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

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

                _source.println(")\"");
                _source.print(_indent);
                _source.println("            << std::endl;");
            }

            _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 number of 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.
        if (_guardIndex > 0 && nullCondition == false)
        {
            // If there is only one transition definition, then
            // close off the guard.
            if (_guardCount == 1)
            {
                _source.print(_indent);
                _source.println("    }");
            }

            _source.print(_indent);
            _source.println("    else");
            _source.print(_indent);
            _source.println("    {");
            _source.print(_indent);
            _source.print("         ");
            _source.print(mapName);
            _source.print("_Default::");
            _source.print(transName);
            _source.print("(context");

            // Output user-defined parameters.
            for (SmcParameter param: transition.getParameters())
            {
                _source.print(", ");
                _source.print(param.getName());
            }
            _source.println(");");
            _source.print(_indent);
            _source.println("    }");
        }
        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();

        // 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.indexOf("::") < 0)
        {
            endStateName = mapName + "::" + endStateName;
        }

        // Qualify the state name as well.
        if (stateName.indexOf("::") < 0)
        {
            stateName = mapName + "::" + stateName;
        }

        loopbackFlag =
            isLoopback(transType, stateName, endStateName);

        // v. 2.0.2: If the push state is not fully-qualified,
        // then prepend the current map's name and make if
        // fully-qualified.
        if (pushStateName != null &&
            pushStateName.length() > 0 &&
            pushStateName.indexOf("::") < 0)
        {
            pushStateName = mapName + "::" + pushStateName;
        }

        // 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 + "        ";

            // More than one guard. Is this the first guard?
            if (_guardIndex == 0 && condition.length() > 0)
            {
                // Yes, this is the first. This means an
                // "if" should be used for this condition.
                _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" for
                // the condition.
                _source.println();
                _source.print(_indent);
                _source.print("    else if (");
                _source.print(condition);
                _source.println(")");
                _source.println(_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("    {");
            }
        }
        else
        {
            // There is only one guard. Does this guard have a
            // condition.
            if (condition.length() == 0)
            {
                // Actually, this is a plain, old, vaniila
                // transition.
                indent2 = _indent + "    ";
            }
            else
            {
                // Yes, there is a condition.
                _source.print(_indent);
                _source.print("    if (");
                _source.print(condition);
                _source.println(")");
                _source.print(_indent);
                _source.println("    {");
                indent2 = _indent + "        ";
            }
        }

        // Now that the necessary conditions are in place, it's
        // time to dump out the transitions 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 (actions.size() == 0 && endStateName.length() > 0)
        {
            fqEndStateName = endStateName;
        }
        else if (actions.size() > 0)
        {
            // Save away the current state if this is a loopback
            // transition. Storing current state allows the
            // current 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 so.
            if (loopbackFlag == true)
            {
                fqEndStateName = "EndStateName";

                _source.print(indent2);
                _source.print(context);
                _source.print("State& ");
                _source.print(fqEndStateName);
                _source.println(" = context.getState();");
                _source.println();
            }
            else
            {
                fqEndStateName = endStateName;
            }
        }

        // Decide if runtime loopback checking must be done.
        if (defaultFlag == true &&
            transType == Smc.TRANS_SET &&
            loopbackFlag == false)
        {
            _source.print(indent2);
            _source.println(
                "if (strcmp(context.getState().getName(), ");
            _source.print(indent2);
            _source.print("           ");
            _source.print(fqEndStateName);
            _source.println(".getName())");
            _source.print(indent2);
            _source.println("       == 0)");
            _source.print(indent2);
            _source.println("{");
            _source.print(indent2);
            _source.println("    loopbackFlag = true;");
            _source.print(indent2);
            _source.println("}");
            _source.println();
        }

        // Before doing anything else, perform the current
        // state's exit actions.
        // v. 1.0, beta 3: Not any more. The exit actions are
        // executed only if 1) this is a standard, non-loopback
        // transition or a pop transition.
        if (transType == Smc.TRANS_POP ||
            loopbackFlag == false)
        {
            indent4 = indent2;

            // If this is a non-loopback, generic transition,
            // do runtime loopback checking.
            if (transType == Smc.TRANS_SET &&
                defaultFlag == true)
            {
                indent4 = indent2 + "    ";
                _source.print(indent2);
                _source.println("if (loopbackFlag == false)");
                _source.print(indent2);
                _source.println("{");
            }

            _source.print(indent4);
            _source.println(
                "(context.getState()).Exit(context);");

            if (transType == Smc.TRANS_SET &&
                defaultFlag == true)
            {
                _source.print(indent2);
                _source.println("}");
                _source.println();
            }
        }

        if (actions.size() > 0)
        {
            // Now that we are in the transition, clear the
            // current state.
            _source.print(indent2);
            _source.println("context.clearState();");
        }

        // Dump out this transition's actions.
        if (actions.size() == 0)
        {
            if (condition.length() > 0)
            {
                _source.print(indent2);
                _source.println("// No actions.");
            }

            indent3 = indent2;
        }
        else
        {
            // v. 2.0.2: Place the actions inside a try/catch
            // block. This way the state will be set before an
            // exception leaves the transition method.
            // v. 2.2.0: Check if the user has turned off this
            // feature first.
            if (Smc.isNoCatch() == false)
            {
                _source.print(indent2);
                _source.println("try");
                _source.print(indent2);
                _source.println("{");

                indent3 = indent2 + "    ";
            }
            else
            {
                indent3 = indent2;
            }

            indent4 = _indent;
            _indent = indent3;

            for (SmcAction action: actions)
            {
                action.accept(this);
            }

            _indent = indent4;
        }

        // Print the setState() call, if necessary. Do NOT
        // generate the set state if:
        // 1. The transition has no actions AND is a loopback OR
        // 2. This is a push or pop transition.