Expression help - Evaluation does not happen with dot notation

Flowable Engine
1

Hi all,

I have an HTTP task that returns me this JSON:

{
  "Results": {
    "output1": {
      "type": "table",
      "value": {
        "ColumnNames": [
          "Scored Labels",
          "Scored Probabilities"
        ],
        "ColumnTypes": [
          "String",
          "Double"
        ],
        "Values": [
          [
            "4",
            "0.648628652095795"
          ]
        ]
      }
    }
  }
}

Short Version:, I’m having trouble evaluating against values that are in an array. I can retrieve them just fine, but when I compare them like so:

 ${responseVar.Results.output1.value.Values.get(0).get(0) == '4' }

The expression never works. I have no problems when doing it against any value that’s not in an array. Is the syntax incorrect when I have to use the .get() functions?

======== Detailed Explanation ========

I’m storing this output as JSON in a variable and want to use it later on in my process in a next task. The way I’m using this information is I have an exclusive gateway with 2 sequence flow branches.

Logically, it should be very simple. If the following value is 4, I want it go to in one direction. If not, I want it to go to the other. This is the value I’m talking about (first element in the nested array):

"Values": [
      [
        "4"  <--- This one,
        "0.648628652095795"
      ]
    ]

I retrieve the value like so, it works perfectly:

${responseVar.Results.output1.value.Values.get(0).get(0)}

Now I want to evaluate if the value is equal to “4” or not. It’s a simple string. The expression is like so:

${responseVar.Results.output1.value.Values.get(0).get(0) == '4' }

This does not evaluate, and I get this error:

no outgoing sequence flow of the exclusive gateway could be selected for continuing the process

I’ve done some debugging to see the output on some forms, and that expression evaluates to a string version of the expression itself, so something didn’t work.

For comparison, I tried the following syntax for an expression to get the value of type:

${responseVar.Results.output1.type == 'table'}

This works perfectly! Hypothesizing that this has something to do with my results being in an array, I tried evaluating against the first element in the ColumnNames array:

${responseVar.Results.output1.value.ColumnNames.get(0) == 'Scored Labels'}

It didn’t work. Same issue as before.

All this to say, is there something different I should be doing syntactically to evaluate against my chosen values if they’re retrieved from an array and I’m using the .get() function?

Any help would be greatly appreciated! Thank you!

2

Hi,

no outgoing sequence flow of the exclusive gateway could be selected for continuing the process

Means that expression ${responseVar.Results.output1.value.Values.get(0).get(0) == '4' } was resolved, but result is false. I would expect responseVar.Results.output1.value.Values.get(0).get(0) returns kind of object, and that’s why expression is evaluated to false. Could you debug process flowhttps://blog.flowable.org/2018/05/30/process-debugger/ and evaluate expression after the call?

Regards
Martin