Groovy, E/PBCS, and Random() stuff....

My last few posts were talking about EPBCS and the newest (most powerful and exciting) feature added recently to the cloud which is Groovy scripting! My background is computer science and naturally, I was super excited about the latest addition and started instantly writing scripts and playing around with it.

Thanks to Celvin Kattookaran who read the Groovy posts and his valuable feedback, he suggested a simpler way of writing the code, and after we exchanged some comments it turned out I was using an old version of the API and he got me in touch with the Oracle Calculation Manager development team, who were kind enough (Thank you Ujwala Maheshwari!) to call me and give me some updates and insights on the latest Groovy scripting feature, as well as the current API library and some of the examples provided. So I thought I should share some of the points/findings:

Some of the pre-built EPBCS Groovy rules are written using the old API version

This is going to be updated soon (maybe as early as August 2017), Good thing that the API library has a lot of useful examples, to access this library go to Academy Groovy Javadocs and simply enjoy! The documentation provided by Oracle here is superb, very clear, powerful and well-written examples, this must be in your browser's favorites

Groovy is simpler than Java

I come from computer science background, I learned to program first using low-level languages (Assembly) and then moved to high-level languages (Pascal, C, VB and Java), why am I mentioning this? because you're very likely to start scripting in Java and totally forget how awesome and groovy Groovy the language is! So what is wrong with writing code in Java? Nothing, but if you can achieve the same result with fewer lines that look more aesthetic then why not?

I will give a very simple example to highlight the above, consider a script that prints Hello World and the current day, this is the first thing you'll learn how to write in any programming language, I'll write the same in Java and Groovy and see where they are different.

Java

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import java.util.Date; import java.text.*; public class Main{ public static void main(String[] args) { DateFormat dateFormat = new SimpleDateFormat("EEE, MMM d, yyyyy"); Date date = new Date(); System.out.println("Hello, World! Today is: " + dateFormat.format(date)); } }

Output

Groovy

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import java.text.* DateFormat dateFormat = new SimpleDateFormat("EEE, MMM d, yyyyy") Date date = new Date() println("Hello, World! Today is: " + dateFormat.format(date))

Output

So, what do you think? Groovy certainly looks nicer and more concise, I wanted to add the date bit because I wanted to highlight some differences between Java and Groovy in the given example:

1. In Groovy, java.util package is imported by default, hence the import line is missing from my Groovy script unlike Java where you need to import every package/class you intend to use.

2. In my Groovy script I don't have a class and method declaration like Java, so if you just want to print Hello World you just need

println("Hello World!")

3. To get formatted dates, you need DateFormat and SimpleDateFormat classes, in both Groovy and Java you need to import the classes

4. Another difference is the semi-colons, in Groovy I don't need to end my lines with ";"

For a more detailed list of differences click here



You can write a perfectly functioning Groovy script and then realize it's really a Java script

One of the first scripts I wrote when I was testing Groovy in EPBCS was a data validation script to prevent users from entering negative values, so the first time I wrote the code it was exactly like this:

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EPMApplicationShell appshell = new EPMApplicationShell() DataGrid grid = null; // exit if rule is executed from Rules launcher try { grid = appshell.getCurrentGrid() } catch(BindingsMissingException) { return '''BegBalance ( @Return("Please run the rule from the dataform"),Error); )''' } //validate negative value GridIterator itr = grid.dataCellIterator() itr.each{ DataCell dc = it if ((dc.isEdited()) && (dc.data <0)) { dc.addValidationError(0xFF6347,"Cannot enter negative numbers") } }

Lines 1 to 10 are there to make sure the script is launched in a form/grid and not Rules launcher, I borrowed this code from Trend Calculation Groovy rule in PBCS, and apparently this is the alpha version and we no longer need to define appshell variable or write the try catch statement. (leave it for now, I'll come back for it).

Lines 11 to 18 Invokes a Grid Iterator and checks edited data cells, and if negative values are found then throw an error.

Now, the following is the refined code:

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// Validate negative value operation.grid.dataCellIterator{DataCell cell -> cell.edited}.each { DataCell cell -> if ((cell.data < 0)) cell.addValidationError(0xFF6347, "Cannot enter negative numbers") }

Oracle Calc Manager were kind enough to re-write my code and they explained the redundant bits.

Lines 1 to 10 are no longer needed and is simply replaced with "operation.grid", so when you try to run the rule above from Rules Launcher it will throw an error "grid not found" because of operation.grid.* which assumes there is an active grid, otherwise throw error and break.

Lines 12 to 18 can be replaced by a simple Closure block, coming from Java background the concept is still new to me, but that is what makes Groovy beautiful and easy to use!


Groovy in Action

Want to learn more about Groovy? Check this out, I'm enjoying this book and most importantly it is really fun to read! It is not written in a typical academic computer science text book style, which means it is fun to read, I don't remember ever enjoying reading my text books back at university. (You can get a combo deal at manning publications which includes a pdf, epub, and soft cover paper version)

What kind of subscription you need to have Groovy your POD? PBCS? PBCS + 1 module? or EPBCS?

Thanks to Shankar Viswanathan  Oracle Planning Product Management, I got this point clarified:

Groovy is technically made available for EPBCS App type which is different from saying it is only for EPBCS. There are three SKUs that customers can buy: PBCS; PBCS + 1 module option; EPBCS. If you buy the PBCS +1 module option you can still deploy the application as EPBCS App Type or convert from PBCS App Type to EPBCS App Type. It is just that contractually you can't deploy more than 1 module when you buy PBCS + 1 module. To get Groovy all you need is to have EPBCS App Type. To use groovy you don't even have to deploy any modules once you are in this EPBCS App Type. So technically it is available for PBCS as long as at least the PBCS + 1 module option is bought by the customer. You could be using just the custom cubes in EPBCS App Type and still use Groovy. There is no current plans to make it available for standalone PBCS. Hope this can be clarified in your future posts.



Yes, that is right you can have Groovy with PBCS as long as you go for the plus module option, if you ask me is it worth it? my answer is...

YES         YES       YES      YES