StringStream class for Arduino

StringStream.h

#ifndef _STRING_STREAM_H_INCLUDED_
#define _STRING_STREAM_H_INCLUDED_

#include <Stream.h>

class StringStream : public Stream
{
public:
    StringStream(const String &s) : string(s), position(0) { }

    // Stream methods
    virtual int available() { return string.length() - position; }
    virtual int read() { return position < string.length() ? string[position++] : -1; }
    virtual int peek() { return position < string.length() ? string[position] : -1; }
    virtual void flush() { };
    // Print methods
    virtual size_t write(uint8_t c) { string += (char)c; };

private:
    String &string;
    int length;
    int position;
};

#endif // _STRING_STREAM_H_INCLUDED_

Remove const on line 9.
Also change line 17 to virtual size_t write(uint8_t c) { string += (char)c; return 1; };
And, to fix the compiler warnings, lines 21/22 to:
unsigned int length;
unsigned int position;

would it be possible to achieve some thing like this:

StringStream sqlQuery;
    sqlQuery  << "INSERT INTO arduinoSensorData.sensorLog (out_temperature,  " 
        << "out_humidity,  drwngRoom_temperature, drwngRoom_humidity, "
        << "pot1_soilMoisture, pot1_avg_SoilMoisture, wateringPot1) VALUES ('" 
        << outdoorTempInC << "', '" << outoorHumidity << "', '" << indorTempinC
        << "', '" << humidity << "', '" << val << "', '" << avgVal << "', '"
        << statusMsg << "');";

tried it gives an error,

error: no matching function for call to 'StringStream::StringStream()'
     StringStream sqlQuery;

how do I achieve the above ?

@sanfx, this is really late, but you would have to implement a operator<< for the class.