smctclgenerator.java

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

        if (stateName.equals("Default") == true)
        {
            _source.print(_indent);
            _source.println("        set loopbackFlag 0;");
            _source.println();

            // Remember this transition's name.
            _source.print(_indent);
            _source.print("        set _transition \"");
            _source.print(transName);
            _source.println("\";");
        }
        else
        {
            _source.println();
        }

        // If verbose is turned on, then put the logging code in.
        if (Smc.isDebug() == true)
        {
            String sep;

            _source.print(_indent);
            _source.println(
                "        if {[$context getDebugFlag] != 0} {");
            _source.print(_indent);
            _source.print(
                "            puts [$context getDebugStream] ");
            _source.print("\"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();
        }

        for (git = guards.iterator(),
                 _guardIndex = 0,
                 _guardCount = guards.size();
             git.hasNext() == true;
             ++_guardIndex)
        {
            guard = git.next();

            // Track if there is a guard with no condition.
            if (guard.getCondition().length() == 0)
            {
                nullCondition = true;
            }

            guard.accept(this);
        }

        // What if all the guards have a condition? There will be
        // no "else" clause. This condition will fall through and
        // do nothing? Is that right? No. If that is the case,
        // then add the "else" clause and have it call this
        // transition's default.
        if (_guardIndex > 0 && nullCondition == false)
        {
            if (_guardCount == 1)
            {
                _source.print(_indent);
                _source.print("        }");
            }

            _source.println(" else {");
            _source.print(_indent);
            _source.print("            ");
            _source.print(mapName);
            _source.print("_Default ");
            _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();
        }
        else
        {
            _source.println();
        }

        _source.print(_indent);
        _source.println("        return -code ok;");
        _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_STATE) == false &&
            endStateName.indexOf("::") < 0)
        {
            endStateName = mapName + "::" + endStateName;
        }

        if (stateName.indexOf("::") < 0)
        {
            stateName = mapName + "::" + stateName;
        }

        // 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;
        }

        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)
        {
            // Ok, there are multiple guard statements. Now is
            // this the first guard among many?
            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("} {");
            }
            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.print(" elseif {");
                _source.print(condition);
                _source.println("} {");
            }
            else
            {
                // This is not the first transition and it has
                // no condition.
                _source.println(" else {");
            }

            indent2 = _indent + "            ";
        }
        // There is only one guard. Does this guard have a
        // condition.
        else if (condition.length() == 0)
        {
            // Actually, this is a plain, old, vaniila
            // transition.
            indent2 = _indent + "        ";
        }
        else
        {
            indent2 = _indent + "            ";

            // Yes, there is a condition.
            _source.print(_indent);
            _source.print("        if {");
            _source.print(condition);
            _source.println("} {");
        }

        // If this is a pop transition, do not change the
        // "end state" name because it is really a transition.
        if (transType == Smc.TRANS_POP)
        {
            // no-op.
        }
        // 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.
        else if (actions.size() == 0 &&
                 endStateName.length() != 0)
        {
            endStateName = "${" + _pkgScope + endStateName + "}";
        }
        else if (actions.size() > 0)
        {
            // Save away the current state if this is a loopback
            // transition. Storing current state allows the
            // current to be cleared before any actions are
            // executed. Remember: actions are not allowed to
            // issue transitions and clearing the current state
            // prevents them from doing so.
            if (loopbackFlag == true)
            {
                endStateName = "${EndStateName}";
                _source.print(indent2);
                _source.println(
                    "set EndStateName [$context getState];");
            }
            else
            {
                endStateName =
                    "${" + _pkgScope + endStateName + "}";
            }
        }

        // Decide if runtime loopback checking must be done.
        if (defaultFlag == true &&
            transType == Smc.TRANS_SET &&
            loopbackFlag == false)
        {
            _source.print(_indent);
            _source.print("        if {[string compare ");
            _source.print("[[$context getState] getName] [");
            _source.print(endStateName);
            _source.println(" getName]] == 0} {");
            _source.print(_indent);
            _source.println("            set loopbackFlag 1;");
            _source.print(_indent);
            _source.println("        }");
            _source.println();
        }

        // Perform the current state's exit action.
        // 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 == 0} {");
            }

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

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

        // Dump out this transition's actions.
        if (actions.size() == 0)
        {
            indent3 = indent2;

            if (condition.length() > 0)
            {
                _source.print(indent2);
                _source.println("# No actions.");
            }
        }
        else
        {
            // Now that we are in the transition, clear the
            // current state since we are no longer in a state.
            _source.print(indent2);
            _source.println("$context clearState;");

            // v. 2.0.2: Place the actions inside a catch block.
            // If one of the actions raises an error, the catch
            // block will make sure the state is set before
            // re-raising the error.
            // v. 2.2.0: Check if the user has turned off this
            // feature first.
            if (Smc.isNoCatch() == false)
            {
                indent3 = indent2 + "    ";

                _source.print(indent2);
                _source.println("if [catch {");
            }
            else
            {
                indent3 = indent2;
            }

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

            // v. 2.2.0: Check if the user has turned off this
            // feature first.
            if (Smc.isNoCatch() == false)
            {
                _source.print(indent2);
                _source.println("} result] {");

                // v. 2.0.2: Generate the set state, push or pop
                // code for the if's then body. Note: the catch
                // body was generated only if there were actions.
                if (transType == Smc.TRANS_SET)
                {
                    _source.print(indent3);
                    _source.print("$context setState ");
                    _source.print(endStateName);
                    _source.println(";");
                }
                else if (transType == Smc.TRANS_PUSH)
                {
                    _source.print(indent3);
                    _source.print("$context setState ");
                    _source.print(endStateName);
                    _source.println(";");

                    // Before doing the push, execute the end
                    // state's entry actions (if any) if this is
                    // not a loopback.
                    if (loopbackFlag == false)
                    {
                        indent4 = indent3;

                        if (defaultFlag == true)
                        {
                            indent4 = indent3 + "    ";

                            _source.println();
                            _source.print(indent3);
                            _source.println(
                                "if {$loopbackFlag == 0} {");