smcscalagenerator.java

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

        {
            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(") {");
            }
            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(") {");
            }
            else
            {
                // This is not the first transition and it has
                // no condition.
                _source.println();
                _source.print(_indent);
                _source.println("    else {");
            }
        }
        // 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(") {");
        }

        // 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("val ");
            _source.print(fqEndStateName);
            _source.println(" = context.getState()");
        }
        else
        {
            fqEndStateName = endStateName;
        }

        // Decide if runtime loopback checking must be done.
        if (defaultFlag == true &&
            transType != Smc.TRANS_POP &&
            loopbackFlag == false)
        {
            _source.print(indent2);
            _source.print("val loopbackFlag: Boolean = ");
            _source.print("context.getState().getName() == ");
            _source.print(fqEndStateName);
            _source.println(".getName()");
        }

        _source.println();

        // Dump out the exit actions - but only for the first
        // guard.
        // 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) {");
            }

            _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 (hasActions == false)
        {
            if (condition.length() > 0)
            {
                _source.print(indent2);
                _source.println("// No actions.");
            }

            indent3 = indent2;
        }
        else
        {
            // Now that we are in the transition, clear the
            // current state.
            _source.print(indent2);
            _source.println("context.clearState()");

            // v. 2.0.0: Place the actions inside a try/finally
            // 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 {");

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

            indent4 = _indent;
            _indent = indent3;

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

            _indent = indent4;

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

        // Print the setState() call, if necessary. Do NOT
        // generate the set state it:
        // 1. The transition has no actions AND is a loopback OR
        // 2. This is a push or pop transition.
        if (transType == Smc.TRANS_SET &&
            (hasActions == true || loopbackFlag == false))
        {
            _source.print(indent3);
            _source.print("context.setState(");
            _source.print(fqEndStateName);
            _source.println(")");
        }
        else if (transType == Smc.TRANS_PUSH)
        {
            // Set the next state so this it can be pushed
            // onto the state stack. But only do so if a clear
            // state was done.
            if (loopbackFlag == false || hasActions == true)
            {
                _source.print(indent3);
                _source.print("context.setState(");
                _source.print(fqEndStateName);
                _source.println(")");
            }

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

                    _source.println();
                    _source.print(indent3);
                    _source.println(
                        "if (!loopbackFlag) {");
                }
                else
                {
                    indent4 = indent3;
                }

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

                if (defaultFlag == true)
                {
                    _source.print(indent3);
                    _source.println('}');
                }
            }

            _source.print(indent3);
            _source.print("context.pushState(");
            _source.print(pushStateName);
            _source.println(")");
        }
        else if (transType == Smc.TRANS_POP)
        {
            _source.print(indent3);
            _source.println("context.popState()");
        }

        // Perform the new state's enty actions.
        // v. 1.0, beta 3: Not any more. The entry actions are
        // executed only if 1) this is a standard, non-loopback
        // transition or a push transition.
        if ((transType == Smc.TRANS_SET &&
             loopbackFlag == false) ||
             transType == Smc.TRANS_PUSH)
        {
            indent4 = indent3;

            // If this is a non-loopback, generic transition,
            // do runtime loopback checking.
            if (transType == Smc.TRANS_SET &&
                defaultFlag == true)
            {
                indent4 = indent3 + "    ";

                _source.println();
                _source.print(indent3);
                _source.println("if (!loopbackFlag) {");
            }

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

            if (transType == Smc.TRANS_SET &&
                defaultFlag == true)
            {
                _source.print(indent3);
                _source.println('}');
                _source.println();
            }
        }

        // If there was a try/finally, then put the closing
        // brace on the finally block.
        // v. 2.2.0: Check if the user has turned off this
        // feature first.
        if (hasActions == true && Smc.isNoCatch() == false)
        {
            _source.print(indent2);
            _source.println('}');
        }

        // If there is a transition associated with the pop, then
        // issue that transition here.
        if (transType == Smc.TRANS_POP &&
            endStateName.equals(NIL_STATE) == false &&
            endStateName.length() > 0)
        {
            String popArgs = guard.getPopArgs();

            _source.println();
            _source.print(indent2);
            _source.print("context.");
            _source.print(endStateName);
            _source.print("(");

            // Output any and all pop arguments.
            if (popArgs.length() > 0)
            {
                _source.print(popArgs);
            }
            _source.println(")");
        }

        // If this is a guarded transition, it will be necessary
        // to close off the "if" body. DON'T PRINT A NEW LINE!
        // Why? Because an "else" or "else if" may follow and we
        // won't know until we go back to the transition source
        // generator whether all clauses have been done.
        if (_guardCount > 1)
        {
            _source.print(_indent);
            _source.print("    }");
        }

        return;
    } // end of visit(SmcGuard)

    public void visit(SmcAction action)
    {
        String name = action.getName();
        Iterator<String> it;
        String sep;

        // Need to distinguish between FSMContext actions and
        // application class actions. If the action is
        // "emptyStateStack", then pass it to the context.
        // Otherwise, let the application class handle it.
        _source.print(_indent);
        if (name.equals("emptyStateStack") == true)
        {
            _source.print("context.");
        }
        else
        {
            _source.print("ctxt.");
        }
        _source.print(name);
        _source.print("(");

        for (it = action.getArguments().iterator(), sep = "";
             it.hasNext() == true;
             sep = ", ")
        {
            _source.print(sep);
            _source.print(it.next());
        }

        _source.println(")");

        return;
    } // end of visit(SmcAction)

    public void visit(SmcParameter parameter)
    {
        _source.print(parameter.getName());
        _source.print(": ");
        _source.print(parameter.getType());

        return;
    } // end of visit(SmcParameter)

//---------------------------------------------------------------
// Member data
//
} // end of class SmcScalaGenerator

//
// CHANGE LOG
// $Log: SmcScalaGenerator.java,v $
// Revision 1.4  2008/03/21 14:03:17  fperrad
// refactor : move from the main file Smc.java to each language generator the following data :
//  - the default file name suffix,
//  - the file name format for the generated SMC files
//
// Revision 1.3  2008/02/06 09:34:24  fperrad
// add getName()
//
// Revision 1.2  2008/02/06 09:07:03  fperrad
// Scala 2.3 -> 2.6
//
// Revision 1.1  2008/02/04 10:32:49  fperrad
// + Added Scala language generation.
//
//