一个链表节点，治好了我的精神内耗

aaa

极其简单的结构，但是利用这个，就可以实现一个游戏编程中，大多数需要不定结构的数据的情景

有点类似MIPS吧，算是我之前看了半天那个内容后终于想明白的东西

对于大多数数据，我们可以都只使用这个链表将它组织，剩下只需要去写相应的decoder就行

aaa

private void message_decoder(Body body, MessageNode message) {

        if (message.stringMessage != null) {

            switch (message.stringMessage) {

                case MESSAGE_APPLY_FORCE: {

                    instruct_apply_force(body, message);

                    break;

                }

            }

        }

    }

aaa

private void instruct_apply_force(Body body, MessageNode message) {
        Vector2 dir = new Vector2(), pos = body.getPosition();
        boolean is_wake = true;
        int strength = -1;

        MessageNode temp = message;

        //skip the head node (which is processed in the upper structure )
        while (temp.has_next) {
            temp = temp.next;
            boolean end_while = false;
            if (temp.stringMessage != null) {
                switch (temp.stringMessage) {
                    case MESSAGE_DIRECTION_X: {
                        dir.x = message.intMessage;
                        break;
                    }
                    case MESSAGE_DIRECTION_Y: {
                        dir.y = message.intMessage;
                        break;
                    }
                    case MESSAGE_STRENGTH:{
                        strength=message.intMessage;
                        break;
                    }
                    case MESSAGE_END: {
                        end_while = true;
                        // if this part of message ends while there are still another message left,
                        // go ahead and process them in the decoder
                        if (temp.has_next) {
                            message_decoder(body, temp.next);
                        }
                        break;
                    }
                }
            }
            if (end_while) {
                break;
            }
        }
        if (strength != -1) {
            dir = PhysicsTool.standard_strength(dir, strength);
        }

        body.applyForce(dir,
                pos, is_wake);
    }