Multi-instance Tasks (loops):

Any Task can have multi-instance either Sequential or Parrallel

Loops have a unique data structure to support multiple items for same node with each of unique data

We will use an example to illustrate the use of loops: - We would like to conduct a poll on various departments about new projects coming up - We will retrieve department list from a DB using Get Department List service task - For each department will initiate a subProcess department with a multi-instance

Defining loop collection

• Input Collection is defined as an Array, defines the multipicity of the node.
• Each value in the collection becomes a key to item

• Since we like to have various departments vote at any time, we make the multi-instance parallel
• Inside the subprocess instance will assign users and designate more information about the vote in Prepare for a vote
• A User Task vote to allow desigated users/user groups to vote with some input fields
• After all department complete their vote, another task Summarize Votes will process the results

Data structure

• Each loop instance stores its own unique data elements, for subProcess loops data is shared among all node items inside the subprocess

So the data structure looks like:

Loop name

Key

data

department: {
    IT: {
      scriptLog: 'added by script event,key:IT',
      votedBy: 'IT-User',
      vote: 85
    },
    HR: {
      scriptLog: 'added by script event,key:HR',
      votedBy: 'HR-User',
      vote: 100
    },
    Billing: {
      scriptLog: 'added by script event,key:Billing',
      votedBy: 'Billing-User',
      vote: 80
    }
  }

Any node inside the loop will share same data, so inside 'HR'

  console.log(item.data.vote,'for ',item.itemKey);

Will produce: 100 for HR.

However, Summarize Votes task is outside the subprocess and at the root, so it has the instance data structure So once you have access to instance data:

  Object.keys(item.data.department).forEach(key=>{
    console.log('Vote for:',key,item.data.department[key]['vote']);

  });

will produce:

Vote for: IT 100
Vote for: HR 85
Vote for: Billing 80

Data Search

• During the execution, either through an event or a script/service task

    item.token.execution.getItems().filter(itm=>(itm.elementId=='Activity_vote')).forEach(voteItem=>{

        let vote =voteItem['data']['vote'];
        let dept=voteItem.itemKey;

        console.log("vote Item",voteItem.seq,'dept:',dept,'vote',vote);

    });

• In a detached fashion, like a batch job or remote access

    let items=await api.data.findItems({"items.elementId":'Activity_vote',"data.caseId":1050});
    items.forEach(voteItem=>{

        let vote =voteItem['data']['vote'];
        let dept=voteItem.itemKey;

        console.log("vote Item",voteItem.seq,'dept:',dept,'vote',vote);

    });

• Search for a particular item by key:

    let items=await api.data.findItems({"items.elementId":'Activity_vote',"items.itemKey":"HR"});