Automatically Set sub-task due date to be 5 days before Parent due date

[Adam George]

I need to be able to set the due date of Sub-tasks based on the Due date of the Parent. Ideally this needs to be 5 working days before. I currently have the code below which sets the due date on the parent to be 30 days after the date entered in Custom field "Received Date". I have been trying to reuse it for the sub task date auto set mentioned above but I'm not having any luck! Any ideas would be greatly appreciated!

Thanks!

import com.atlassian.jira.issue.MutableIssue
import com.atlassian.jira.issue.UpdateIssueRequest
import java.sql.Timestamp;
import com.atlassian.jira.component.ComponentAccessor;
import com.atlassian.jira.issue.Issue
import com.atlassian.jira.event.type.EventDispatchOption

int days = 30;

Calendar dueDate = Calendar.getInstance();
dueDate.setTime( (Date) issue.getCustomFieldValue(ComponentAccessor.getCustomFieldManager().getCustomFieldObjectByName("Received Date")));

while (days != 0)
{
    dueDate.add(Calendar.DAY_OF_YEAR, 1);
    if((dueDate.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY) || (dueDate.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY))
        continue;
    
    --days;
}


issue.setDueDate (new Timestamp (dueDate.getTime().getTime()));