class ActionEnter {

	private HttpServletRequest request = null;

	private String rootPath = null;
	private String contextPath = null;

	private String actionType = null;

	private ConfigManager configManager = null;

	public ActionEnter ( HttpServletRequest request, String rootPath, String userId) {

		this.request = request;
		this.rootPath = rootPath;
		this.actionType = request.getParameter( "action" );
		this.contextPath = request.getContextPath();
		this.configManager = ConfigManager.getInstance( this.rootPath, this.contextPath, request.getRequestURI(), userId );

	}

	public String exec () {

		String callbackName = this.request.getParameter("callback");
		if ( callbackName != null ) {
			if ( !validCallbackName( callbackName ) ) {
				return new BaseState( false, AppInfo.ILLEGAL ).toJSONString();
			}
			String ww = callbackName+"("+this.invoke()+");";
			return ww;
		} else {
			return this.invoke();
		}

	}

	public String invoke() {

		if ( actionType == null || !ActionMap.mapping.containsKey( actionType ) ) {
			return new BaseState( false, AppInfo.INVALID_ACTION ).toJSONString();
		}

		if ( this.configManager == null || !this.configManager.valid() ) {
			return new BaseState( false, AppInfo.CONFIG_ERROR ).toJSONString();
		}

		State state = null;

		int actionCode = ActionMap.getType( this.actionType );

		Map<String, Object> conf = null;

		switch ( actionCode ) {

			case ActionMap.CONFIG:
				String config = this.configManager.getAllConfig().toString();
				return config;
			case ActionMap.UPLOAD_IMAGE:
			case ActionMap.UPLOAD_SCRAWL:
			case ActionMap.UPLOAD_VIDEO:
			case ActionMap.UPLOAD_FILE:
				conf = this.configManager.getConfig( actionCode );
				state = new Uploader( request, conf ).doExec();
				break;

			case ActionMap.CATCH_IMAGE:
				conf = configManager.getConfig( actionCode );
				String[] list = this.request.getParameterValues( (String)conf.get( "fieldName" ) );
				state = new ImageHunter( conf ).capture( list );
				break;

			case ActionMap.LIST_IMAGE:
			case ActionMap.LIST_FILE:
				conf = configManager.getConfig( actionCode );
				int start = this.getStartIndex();
				state = new FileManager( conf ).listFile( start );
				break;

		}
		System.out.println("upload state:"+state.toJSONString());

		return state.toJSONString();

	}

	public int getStartIndex () {<FILL_FUNCTION_BODY>}

	/**
	 * callback参数验证
	 */
	public boolean validCallbackName ( String name ) {

		if ( name.matches( "^[a-zA-Z_]+[\\w0-9_]*$" ) ) {
			return true;
		}

		return false;

	}

}


		String start = this.request.getParameter( "start" );

		try {
			return Integer.parseInt( start );
		} catch ( Exception e ) {
			return 0;
		}

	
<no_super_class>