Time Format Alternate Half Year

At ESCB level SDMX data exchanges, there is an agreement to use 'H' as the frequency value for semi-annual observations. This is specified via 'YYYY-H1' or 'YYYY-H2'.

The Registry supports this with a system property. When this is enabled the Registry is in 'alternate half year' mode. Under this mode:

• Frequency value 'H' means half-year (semiannual or semester) as does frequency value 'S'. They are interchangeable as input.
• 'YYYY-S1' and 'YYYY-H1' are valid TIME_PERIOD formats for half-yearly observations.
• Output in SDMX-ML will always be in the 'S' format (e.g. an input of 'YYYY-H1' will be converted to 'YYYY-S1'). This ensures that the output is correct to the SDMX specification.
• Output in other formats will not be converted from 'H' to 'S' (e.g. SDMX-CSV)
• The hourly frequency is not supported.

'Alternate half year' mode is controlled at system level on Registry start-up by setting the Java System variable "TF_ALTERNATE_HALF_YEAR" to "true".

Setting System Property

If using Apache Tomcat, it is recommended to set the value via JAVA_OPTS and using the setenv.bat or setenv.sh file:

SET JAVA_OPTS=-DTF_ALTERNATE_HALF_YEAR=true
(For Windows systems)

export JAVA_OPTS=-DTF_ALTERNATE_HALF_YEAR=true
(For Unix systems)

Different procedures may be required for other web application servers like JBoss.

Is Alternate Half-Year Format set?

On startup the Fusion Registry system log will report the following message:

2021-12-31 23:59:59.123 INFO main io.sdmx.core.fmr.application.FusionRegistryApplicationInitialiser - Using 'Alternate Half-Year' Setting

Active system properties can also be queried using the REST API which is detailed here.