Wednesday, June 24, 2015

Groovy Time! How to use XML dateTime and duration in BPM 12c

In this article I show some examples of handling XML dateTime and durations in Groovy in the context of a Oracle BPM 12c application.

Working with dates and durations in Java has always been painful. Mainly because date and time is a complex thing, with different formats and time zones and all, but I sometimes wonder if it has not been made overly complex. Anyway. Working with XML dates is even more complex because the limited support by XPath functions. Too bad because in BPM applications that work with dates this has to be done very often, and as a result I very often see the need to create all kinds of custom XPath functions to mitigate that.

This issue of complexity is no different for Groovy scripting in Oracle BPM 12c. And let handling of dates be a typical use case for using Groovy scripting because of this limited support by XPath. Therefore, to get you started (and help myself some next time) I would like to share a couple of Groovy code snippets for working with XML dates and durations that may be useful. These example are based on working with the XML dateTime type, and do not handle with the complexity of time zones and different formats. In my practice this is 99% of the use cases that I see.

In my opinion you still should limit using Groovy to handle dates and to the minimum, and rather use custom XPath functions, or create a Java library which you can can import in Groovy. But when you have to, this just might come in handy.

Instantiate an XML Date

If you have an XML element of type dateTime, you use an XmlCalender object. An XmlCalender object with the current time can instantiated as shown below:

Date now = new Date()
GregorianCalendar gregorianNow = new GregorianCalendar()
XmlCalendar xmlDate = XmlCalendarFactory.create(gregorianNow)

Instantiate a Duration and Add it to the Date

To instantiate a duration you use an XmlDuration object. In the code below a duration of one day is added to the date:

XmlDuration xmlDuration = new XmlDuration("P1D")

The string to provide is of type ISO duration.

The imports to use can also be a pain to find. That actually took me the most time of all, but that can just be me. The ones needed for the above are shown in the following picture (you can get to it by using clicking on Select Imports on the top-right corner of the Groovy script.

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