NullValue.h

00001 /*
00002  * NullValue.h
00003  *
00004  * Created on: Nov 1, 2013
00005  * * Authors: Vincent Wochnik <v.wochnik@gmail.com>
00006  *
00007  * Copyright (c) 2013 Cumulocity GmbH
00008  *
00009  * Permission is hereby granted, free of charge, to any person obtaining
00010  * a copy of this software and associated documentation files (the
00011  * "Software"), to deal in the Software without restriction, including
00012  * without limitation the rights to use, copy, modify, merge, publish,
00013  * distribute, sublicense, and/or sell copies of the Software, and to
00014  * permit persons to whom the Software is furnished to do so, subject to
00015  * the following conditions:
00016  *
00017  * The above copyright notice and this permission notice shall be
00018  * included in all copies or substantial portions of the Software.
00019  *
00020  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00021  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00022  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00023  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00024  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00025  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00026  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00027  */
00028 
00029 #ifndef NULLVALUE_H
00030 #define NULLVALUE_H
00031 
00032 #include "config.h"
00033 #include "Value.h"
00034 
00035 /**
00036  * Represents a null value.
00037  * 
00038  * Example:
00039  * @code
00040  * // You may use:
00041  * NullValue nullv;
00042  * // You should use whenever possible:
00043  * aNullValue;
00044  * @encode
00045  */
00046 class NullValue : public Value
00047 {
00048     public:
00049         NullValue();
00050 
00051         virtual uint8_t valueType() const;
00052         virtual long integerValue() const;
00053         virtual double floatValue() const;
00054         virtual const char * characterValue() const;
00055 
00056         virtual size_t write(AbstractDataSink&) const;
00057         virtual size_t length() const;
00058         virtual Value* copy() const;
00059 };
00060 
00061 extern NullValue aNullValue;
00062 
00063 #endif