Application Engine Plug-ins

PeopleTools provides a feature where in we can alter the SQL or PeopleCode actions of any Application Engine program, without customizing the delivered AE program. The configured plug-in action is executed at runtime. This effectively allows us to modify the code without actually customizing or re-designing the Application Engine program.

Configure the selected SQL or PeopleCode action of the Application Engine program by adding new SQL, PeopleCode, or both and/or by replacing the existing SQL or PeopleCode action through PIA in the AE Action Plugin page (PeopleTools, Application Engine).

Note: You can add or replace only SQL and PeopleCode actions in the Application Engine program. Only sections with steps having SQL or PeopleCode actions of the Application Engine program, which you plan to configure, will be displayed in PIA. This feature is not designed to add new sections or steps to an existing Application Engine program.

Actions belonging to the same step of the same section of the Application Engine program can have multiple plug-in actions defined. The plug-in action type does not have to match the action type that is selected for configuration. You can re-use the same SQL or PeopleCode plug-in action multiple times for different Application Engine programs.

The Application Engine action that is being configured cannot be used as a plug-in to configure another Application Engine program. Also, you cannot define a plug-in for the Application Engine action that is already been used as a plug-in.

For example, if Application Engine program A action Y is configured to use Application Engine program B action X as a plug-in, then Application Engine program A action Y cannot be used as a plug-in for any other Application Engine program. Also, you cannot configure a plug-in for Application Engine program B action X.

For the following test I am running PT 8.58.05, HCM 9.2 on PUM 35.

So AEMINITEST is my delivered program and then I created another standard AE program called as N_PLUGIN. My custom AE just has one step with action as peoplecode under MAIN. I have enbled disable restart under object properties of my custom AE.

In my custom peoplecode action I have the following code.

The delivered AE AEMINITEST has 2 steps under MAIN, first one is a SQL and then second one is peoplecode. I added a line of text to the peoplecode to understand the flow (obvisously this is not necessary).

Next logged into PIA and navigated to PeopleTools > Application Engine > AE Action Plugin and pulled up AEMINITEST.

I tried the following 4 tests.

1. Run my peoplecode action after AEMINITEST's peoplecode 

Value of variable TEST in AEMINITEST is 2 (0,0)

Value of variable TEST in N_PLUGIN is 20 (0,0)
Application Engine program AEMINITEST ended normally

Here I tried if I can display the value of the variable in my N_PLUGIN prgram which is set in the parent AEMINITEST program. This would work only if the variable is declared as global or component, not as local or if its auto declared. Similarly values from AET records could possibly be shared.   

2. Run my peoplecode action before AEMINITEST's peoplecode

Value of variable TEST in N_PLUGIN is 20 (0,0)

Value of variable TEST in AEMINITEST is 2 (0,0)
Application Engine program AEMINITEST ended normally

3. Run my peoplecode action replacing AEMINITEST's peoplecode

Value of variable TEST in N_PLUGIN is 20 (0,0)
Application Engine program AEMINITEST ended normally

4. Replace AEMINITEST's SQL with my peoplecode action

Value of variable TEST in N_PLUGIN is 20 (0,0)

Value of variable TEST in AEMINITEST is 2 (0,0)
Application Engine program AEMINITEST ended normally

So this is a great feature and will definitely assist when customizing Application Engine programs.

XML Parser

XML related API has been around for some time now in PeopleSoft and this post is not discussing anything new. Just something that I wanted to pen down for future reference. 

So recently I have been working on a requirement where in I have to parse out a XML response and fetch data values in order to process them further. In this case the same tag element names repeat throughout the XML message and there are multiple levels in the message. The requirement was to traverse each "item" tag and fetch the value for "key" and "value" tags.

Format of the XML message is as shown below.

<?xml version="1.0" encoding="UTF-8"?> <root> <level1> <level2> <level3> <item> <key>FieldName1</key> <value>Value1</value> <type>String</type> </item> <item> <key>FieldName2</key> <value>Value2</value> <type>Date</type> </item> <item> <key>FieldName3</key> <value>Value3</value> <type>Number</type> </item> </level3> </level2> </level1> </root>



Wrote two methods, first one is way longer than the second one.
For both methods I am passing the "field_name_value" and getting back the &fieldvalue value.


Method one - longer.


Local XmlDoc &NewHireXMLDoc;
Local XmlNode &root, &level1, &level2, &level3, &item;
Local number &z, &y, &x, &w, &v;
Local string &sResp, &fieldvalue;
Local boolean &bRet;


rem &sResp is the XML message in string form;
   
&NewHireXMLDoc = CreateXmlDoc();
&bRet = &NewHireXMLDoc.ParseXmlString(&sResp);

&rootNode = &NewHireXMLDoc.DocumentElement;

For &z = 1 To &rootNode.ChildNodeCount
   If &root.GetChildNode(&z).NodeName = "level1" Then
      &level1= &root.GetChildNode(&z);
      For &y = 1 To &level1.ChildNodeCount
         If &level1.GetChildNode(&y).NodeName = "level2" Then
            &level2= &level1.GetChildNode(&y);
            For &x = 1 To &level2.ChildNodeCount
               If &level2.GetChildNode(&x).NodeName = "level3" Then
                  &level3 = &level2.GetChildNode(&x);
                  For &w = 1 To &level3.ChildNodeCount
                     If &level3.GetChildNode(&w).NodeName = "item" Then
                        &item = &level3.GetChildNode(&w);
                        For &v = 1 To &item.ChildNodeCount
                           If &item.GetChildNode(&v).NodeName = "key" And
                                 &item.GetChildNode(&v).NodeValue = "field_name_value" Then
                              &fieldvalue = &item.GetChildNode(&v + 1).NodeValue;
                              &v = &v + 1;
                           End-If;
                       End-For;
                     End-If;
                  End-For;
               End-If;
            End-For;
         End-If;
      End-For;
   End-If;
End-For;



Method two - shorter

Local XmlDoc &NewHireXMLDoc;
Local string &sResp, &fieldvalue;
Local boolean &bRet;

Local array of XmlNode &items;
Local number &y, &z;

rem &sResp is the XML message in string form;
   
&NewHireXMLDoc = CreateXmlDoc();
&bRet = &NewHireXMLDoc.ParseXmlString(&sResp);


&items = &NewHireXMLDoc.DocumentElement.FindNodes("level1/level2/level3/item");
   
   For &z = 1 To &items.Len
      For &y = 1 To &items [&z].ChildNodeCount
         
         If &items [&z].GetChildNode(&y).NodeName = "key" And
               &items [&z].GetChildNode(&y).NodeValue = "field_name_value" Then
            &fieldvalue = &items [&z].GetChildNode(&y + 1).NodeValue;
            Break;
         End-If;
      End-For;

   End-For;

Creating JSON request for REST web services

PeopleSoft provides Document technology to be used to generate JSON request messages but in my experience they are very restrictive especially when working on integrating with 3rd party web services. So following is what I did to generate a JSON request message to post to a 3rd party REST web service. 

The request that I have to generate is in the following form.
[
   {
      "attrib1":"value1",
      "attrib2":"value2",
      "attrib3":{
         "attrib3_1":"values3_1",
         "attrib3_2":"values3_2",
         "attrib3_3":"values3_3",
         "attrib3_4":"values3_4"
      }
   }
]

I am running PT 8.57.x and at this time its not possible to build a document with the root node as an array as shown in the example below. Also I have nested compounds which is also a challenge, the parent compound does not have a label where as the child does. 
So to build something like above I am using the CreateJsonBuilder API provided by PeopleSoft.

Local JsonBuilder &jbldr = CreateJsonBuilder();
Local JsonArray &jArray;

Local string &json;
Local message &request, &response;
Local boolean &bRet;

&jbldr.StartArray(""); /* no label */
 &jbldr.StartObject(""); /* no label */
  &jbldr.AddProperty("attrib1", "value1");
  &jbldr.AddProperty("attrib2", "value2");
   &jbldr.StartObject("attrib3"); /* need a label */
    &jbldr.AddProperty("attrib3_1", "value3_1");
    &jbldr.AddProperty("attrib3_2", "value3_2");
    &jbldr.AddProperty("attrib3_3", "value3_3");
    &jbldr.AddProperty("attrib3_4", "value3_4");
   &jbldr.EndObject("attrib3"); /* closing out the compound or JSONObject */
 &jbldr.EndObject("");
&jbldr.EndArray("");


/* this will return the array just like what I want */
&jArray = &jbldr.GetRootNode().GetJsonObject().GetJsonArray("");
&json = &jArray.ToString();

Created a basic non-rowset based message and assigned that as the request message in my service operation. Use this method to set the content for the message segment for a non-rowset-based message only.

&bRet = &request.SetContentString(&json);
&response = %IntBroker.SyncRequest(&request);

That's it, works like a charm.

Application Engine Parallel Processing (batch)

Parallel processing comes in picture when there is a requirement to process large amount of rows without compromising the performance which might otherwise get impacted greatly with non-parallel based processing. Sharing this concept with an actual example where this concept has been used.

I had written an application engine program which read data via a SQL object, performed some computations and finally wrote the result to an extract file which was sFTP'ed to the vendor. Pretty much run of the mill stuff. The AE was reading from PS_JOB, PS_PERSONAL_DATA, PS_EMAIL_ADDRESSES tables etc via a single single SQL object in a peoplecode step, performing the data manipulation as required and writing to a file. It was sequentially selecting an employee at a time, performing the data manipulations and writing to the file. To process around 3K employees it was taking a little over an hour, so not a lot of data but too much time to process this data-set.

So to solve this issue of performance, this is what I did. 

1. I created a single TAO or temporary table. The fields in this table are essentially the unique list of fields or values that the single SQL object was returning. Did not build the TAO table yet, will do it in a later step.
2. The TAO table has two keys, PROCESS_INSTANCE and EMPLID.
3. Then before the peoplecode step was called added a new step to select from the various HR tables and write to this newly created TAO table. 
4. SQL step looks something like this.

         INSERT INTO %Table(N_MY_TAO)          SELECT %Bind(PROCESS_INSTANCE)         , B.EMPLID         .....        .....

        .....

        FROM PS_JOB A, PS_PERSONAL_DATA B .....

        WHERE ....

    5. After this added a new step to update statistics on the newly populated TAO table.
        %UpdateStats(N_MY_TAO)
    6. In the Peoplecode step replaced the SQL fetch as follows.
        &EESQL = CreateSQL(FetchSQL(SQL.N_MY_SQL), N_MY_AET.PROCESS_INSTANCE);
    7. I had already defined a state record in my AE which has process_instance field in it, so did not have to do anything different with the state record. In the N_MY_SQL SQL object I am selecting all fields FROM %Table(N_MY_TAO) WHERE PROCESS_INSTANCE = :1 

ORDER BY EMPLID. I have some SQL case statements and formatting rules defined in the SQL itself.

8. Added the newly created TAO table under temp tables program properties and provided an instance count of 1. Instance count has to be 1 or more, if its set to 0 then you will see the following message in your AE log and there won't be much of performance improvement. 

WARNING: NO DEDICATED INSTANCES AVAILABLE FOR N_MY_TAO - USING BASE TABLE. (108,544)

9. Under PeopleTools > Utilities > Administration > PeopleTools Options, in my case the Temp Table Instances (Total) and Temp Table Instances (Online) is set to 3. So when I add 1 as the instance count in my AE and then build the TAO table, it will create PS_N_MY_TAO, PS_N_MY_TAO1, 2, 3 and 4 and when the process runs it will use PS_N_MY_TAO4 as the first 3 are used for online processing. 

10. You can add a step at the beginning or end to purge the TAO table like %TruncateTable (%Table(N_MY_TAO)) or better yet use the check-box under program properties "Use Delete for Truncate Table". With this option the TAO table is purged at the beginning of each run.

Addition of a single TAO table enabled the process to complete in 7 mins. Massive improvement.