干掉if-else，試試狀態(tài)模式！

    public String parseToFullType() throws IllegalStateException {        StringBuilder sb = new StringBuilder();

        for (; ; this.scanner.next()) {            Character currentChar = scanner.current();            if (currentChar == '\uFFFF') {                return sb.toString();            }            if (isCollection()) {                if (CollectionEnd()) {                    dealCollectionEleEnd();                }else {                    throw new IllegalStateException("unexpected char '" + currentChar + "' at position " + scanner.getIndex());                }            } else if (isWrapperType()) {                dealSingleEleEnd();            } else if (parseStart()) {                if (collectionStart()) {                    putCollecitonExpectEle()                }            } else {                throw new IllegalStateException("unknown char '" + currentChar + "' at position " + scanner.getIndex());            }        }

 public interface StateHandler {     /**      * @param event 要處理的事件      * @param states 系統(tǒng)整體狀態(tài)      * @param result 解析的結(jié)果      */     void handle(Event event, Stack<State> states, StringBuilder result); }

public class MapLeftHandler implements StateHandler {    @Override    public void handle(Event event, Stack<State> states, StringBuilder result) {        // 這里是核心的 Action，將單步解析結(jié)果放到最終結(jié)果內(nèi)        result.append(",");        result.append(event.getParsedVal());

        // 狀態(tài)機(jī)的典型處理方式，處理各種事件發(fā)生在當(dāng)前狀態(tài)時(shí)的邏輯        switch (event.getEventType()) {            case MAP:                states.push(State.MAP_START);                break;            case SET:                states.push(State.SET_START);                break;            case LIST:                states.push(State.LIST_START);                break;            case WRAPPED_ELE:                // 使用 pop 或 push 修改棧頂狀態(tài)來(lái)修改解析器的整體狀態(tài)                states.pop();                states.push(State.MAP_RIGHT);                break;            case PRIMITIVE_ELE:                // 當(dāng)前狀態(tài)不能接受的事件類型要拋異常中斷                throw new IllegalStateException("unexpected primitive char '" + event.getCharacter() + "' at position " + event.getIndex());            default:        }    }}

    public static String parseToFullType(String shortenType) throws IllegalStateException {        StringBuilder result = new StringBuilder();        StringCharacterIterator scanner = new StringCharacterIterator(shortenType);        Stack<State> states = new Stack<>();        states.push(State.START);

        for (; ; scanner.next()) {            char currentChar = scanner.current();            if (currentChar == '\uFFFF') {                return result.toString();            }            // 使用整體狀態(tài)為空來(lái)代表解析結(jié)束            if (states.isEmpty()) {                throw new IllegalStateException("unexpected char '" + currentChar + "' at position " + scanner.getIndex());            }            // 將字符規(guī)整成事件對(duì)象，有利于參數(shù)的傳遞            Event event = Event.parseToEvent(currentChar, scanner.getIndex());            if (event == null) {                throw new IllegalStateException("unknown char '" + currentChar + "' at position " + scanner.getIndex());            }
            // 這里需要一個(gè) Map 來(lái)映射狀態(tài)和狀態(tài)處理器            STATE_TO_HANDLER_MAPPING.get(states.peek()).handle(event, states, result);        }    }