bdlt_fixutilconfiguration

Detailed Description

Outline

• Purpose
• Classes
• Description
  • Attributes
  • Default Configuration
  • Usage
    • Example 1: Configuring FIX String Generation
    • Example 2: Setting the Process-Wide Default Configuration

Purpose

Provide an attribute class to configure FIX string generation.

Classes

• bdlt::FixUtilConfiguration: configuration for FIX strings

See also

bdlt_fixutil

Description

This component provides an unconstrained (value-semantic) attribute class, bdlt::FixUtilConfiguration, that may be used to configure various aspects of generated FIX strings.

Attributes

           Name             Type   Default
-------------------------   ----   -------
fractionalSecondPrecision   int     3
useZAbbreviationForUtc      bool    false

• fractionalSecondPrecision: number of digits used to represent fractional seconds; must be in the range 0 .. 6.
• useZAbbreviationForUtc: true if Z should be used for the timezone offset instead of +00:00 (specific to UTC).

Default Configuration

This component also provides a (process-wide) default configuration that may be set and retrieved via the setDefaultConfiguration and defaultConfiguration class methods, respectively. See Usage Example 2 for further details.

Usage

This section illustrates intended use of this component.

Example 1: Configuring FIX String Generation

This example demonstrates creation of a bdlt::FixUtilConfiguration object that may be used to influence the format of the output produced by a hypothetical utility, my::FixUtil, that generates and parses FIX strings for bdlt vocabulary types (see bdlt_fixutil , which provides just such functionality). In particular, suppose that given a sample bdlt::DatetimeTz object:

const bdlt::DatetimeTz datetimeTz(
                           bdlt::Datetime(2005, 1, 31, 8, 59, 59, 123), 0);

my::FixUtil produces, by default, the following string (which is a valid FIX string):

20050131-08:59:59.123+00:00

However, we would like to produce the following (also valid FIX) string instead:

20050131-08:59:59.123000Z

bdlt::FixUtilConfiguration can be used to obtain the desired result assuming that my::FixUtil uses bdlt::FixUtilConfiguration to affect the format of generated strings in this fashion (e.g., again see bdlt_fixutil ).

First, we construct a bdlt::FixUtilConfiguration object that has the default value:

bdlt::FixUtilConfiguration configuration;
assert( configuration.fractionalSecondPrecision() == 3);
assert(!configuration.useZAbbreviationForUtc());

Then, we modify configuration to indicate that we want to use 6 digits of precision in the fractional seconds:

configuration.setFractionalSecondPrecision(6);
assert( configuration.fractionalSecondPrecision() == 6);
assert(!configuration.useZAbbreviationForUtc());

Finally, we modify configuration to indicate that we want to use Z as an abbreviation for UTC:

configuration.setUseZAbbreviationForUtc(true);
assert( configuration.fractionalSecondPrecision() == 6);
assert( configuration.useZAbbreviationForUtc());

Our configuration object can now be supplied to my::FixUtil to produce the desired result.

Example 2: Setting the Process-Wide Default Configuration

This example demonstrates how to establish the process-wide default configuration.

First, we retrieve the default configuration in effect at process start-up and note that it has the default-constructed value:

bdlt::FixUtilConfiguration configuration =
                        bdlt::FixUtilConfiguration::defaultConfiguration();
assert(bdlt::FixUtilConfiguration() == configuration);
assert( configuration.fractionalSecondPrecision() == 3);
assert(!configuration.useZAbbreviationForUtc());

Next, we modify configuration to indicate that we want to output Z when the timezone offset is UTC (i.e., instead of +00:00):

configuration.setUseZAbbreviationForUtc(true);
assert( configuration.fractionalSecondPrecision() == 3);
assert( configuration.useZAbbreviationForUtc());

Then, we modify configuration to display milliseconds:

configuration.setFractionalSecondPrecision(6);
assert( configuration.fractionalSecondPrecision() == 6);
assert( configuration.useZAbbreviationForUtc());

Now, we set the default configuration to the value of our configuration object:

bdlt::FixUtilConfiguration::setDefaultConfiguration(configuration);

Finally, we verify that the default configuration was updated as expected:

const bdlt::FixUtilConfiguration newConfiguration =
                    bdlt::FixUtilConfiguration::defaultConfiguration();
assert( newConfiguration.fractionalSecondPrecision() == 6);
assert( newConfiguration.useZAbbreviationForUtc());

Note that the expected usage is that the process-wide configuration will be established once, early in main, and not changed throughout the lifetime of a process.