/**
 * Make a JSON text of an Object value. If the object has an
 * value.toJSONString() method, then that method will be used to produce the
 * JSON text. The method is required to produce a strictly conforming text.
 * If the object does not contain a toJSONString method (which is the most
 * common case), then a text will be produced by other means. If the value
 * is an array or Collection, then a JSONArray will be made from it and its
 * toJSONString method will be called. If the value is a MAP, then a
 * JSONObject will be made from it and its toJSONString method will be
 * called. Otherwise, the value's toString method will be called, and the
 * result will be quoted.
 * <p>
 * <p>
 * Warning: This method assumes that the data structure is acyclical.
 *
 * @param value
 *         The value to be serialized.
 * @return a printable, displayable, transmittable representation of the
 * object, beginning with <code>{</code>&nbsp;<small>(left
 * brace)</small> and ending with <code>}</code>&nbsp;<small>(right
 * brace)</small>.
 * @throws JSONException
 *         If the value is or contains an invalid number.
 */
static String valueToString(Object value) throws JSONException {
    if (value == null || value == JSONObject.NULL) {
        return "null";
    }

    if (implementsJSONString(value)) {
        String object;
        try {
            object = ((JSONString) value).toJSONString();
        } catch (Exception e) {
            throw new JSONException(e);
        }
        if (object != null) {
            return object;
        }
        throw new JSONException("Bad value from toJSONString: null");
    }
    if (value instanceof Number) {
        // not all Numbers may match actual JSON Numbers. i.e. Fractions or Complex
        final String numberAsString = JSONObject.numberToString((Number) value);
        if (NUMBER_PATTERN.matcher(numberAsString).matches()) {
            // Close enough to a JSON number that we will return it unquoted
            return numberAsString;
        }
        // The Number value is not a valid JSON number.
        // Instead we will quote it as a string
        return JSONObject.quote(numberAsString);
    }
    if (value instanceof Boolean || value instanceof JSONObject
            || value instanceof JSONArray) {
        return value.toString();
    }
    if (value instanceof Map) {
        Map<?, ?> map = (Map<?, ?>) value;
        return new JSONObject(map).toString();
    }
    if (value instanceof Collection) {
        Collection<?> coll = (Collection<?>) value;
        return new JSONArray(coll).toString();
    }
    if (value.getClass().isArray()) {
        return new JSONArray(value).toString();
    }
    if (value instanceof Enum<?>) {
        return JSONObject.quote(((Enum<?>) value).name());
    }
    return JSONObject.quote(value.toString());
}