Iterate over Business process activities

Recently I needed a classmethod that returns annotation value based on a name of a activity.

As doing it at runtime seemed inefficient, I wrote compile-time utility that iterates over all business process activities and generates relevant code.

This code could be used in a variety of situations when you need to iterate over business process activities, just add it as a secondary superclass to your BPL processes.

Class isc.ens.ProcessUtils
{

/// List of nodes that may contain ActivityList.
/// Retrieved with:
/// SELECT  parent, ID,  Name, Type
/// FROM %Dictionary.CompiledProperty
/// WHERE Parent %STARTSWITH 'Ens.BPL' AND Name='Activities'
Parameter ActivityNodes = {$lb("Ens.BPL.Case", "Ens.BPL.CaseNode", "Ens.BPL.Catch", "Ens.BPL.CatchAll", "Ens.BPL.CompensationHandler", "Ens.BPL.Default", "Ens.BPL.Flow", "Ens.BPL.ForEach", "Ens.BPL.Message", "Ens.BPL.Request", "Ens.BPL.Response", "Ens.BPL.Scope", "Ens.BPL.Sequence", "Ens.BPL.Until", "Ens.BPL.While")};

/// Get value of activity annatation by name
ClassMethod GetAnnotation(name) As %String [ CodeMode = objectgenerator ]
{
    set sc = $$$OK
    try {
        #; Don't run this method on the base class
        quit:%compiledclass.Name="isc.py.ens.AbstractBPLProcess"  
        quit:##class(%Dictionary.CompiledXData).%ExistsId(%class.Name_"||BPLERROR")
        
        #; find XDATA block named BPL
        if ##class(%Dictionary.CompiledXData).%ExistsId(%class.Name_"||BPL") {
            set index = %compiledclass.XDatas.FindObjectId(%class.Name_"||BPL")
        
            #; get XDATA as stream
            set stream = %compiledclass.XDatas.GetAt(index).Data
            do stream.Rewind()
    
            set parser=##class(Ens.BPL.Parser).%New()
        
            #; Parse the specified stream and obtain the root of the parse tree,
            #; Ens.BPL.Process
            #dim process As Ens.BPL.Process
            set sc = parser.ParseStream(stream,.process)
            quit:$$$ISERR(sc)
            
            #dim activities As Ens.BPL.ActivityList
            set activities = process.Sequence.Activities
            
            // place all code you want executed before node iteration here
            do ..ParseActivities(activities)
            
            // place all code you want executed after node iteration here
            do %code.WriteLine(" quit """"")
        }
    } catch ex {
        set sc = ex.AsStatus()
    }
    quit sc
}

// Iterate over all activities
ClassMethod ParseActivities(activities As Ens.BPL.ActivityList)
{
    for i=1:1:activities.Count() {
        #dim activity As Ens.BPL.Activity
        set activity = activities.GetAt(i)
        set class = activity.%ClassName(1)
        if $lf(..#ActivityNodes, class) {
            do ..ParseActivities(activity.Activities)
        } elseif (class="Ens.BPL.If") {
            do ..ParseActivities(activity.True)
            do ..ParseActivities(activity.False)
        } elseif (class ="Ens.BPL.Switch"){
            do ..ParseActivities(activity.Cases)
        } else {
            set annotationText = $$$quote(activity.Annotation)
            
            // code that would be executed for each activity
            do:activity.Annotation'="" %code.WriteLine(" quit:name=""" _ activity.Name _ """ " _ annotationText)
        }
    }
}

}