Need help for script debugging for groovy (Set Priority in context to issue.summary)

[Viktor Titko]

We intend on setting The Priority Based on the summary for one of our SD's. For Example exemplarie mail subject "[...](Priority:1)[...]", which creates an issue with the summary [Ticketnumber][...](Priority:1)[...]. 
What we want to do:
1. get the issue.summery content
2. Look up the number after "Priority:"
3. Priority accordingly

Currently used code:

import com.atlassian.jira.issue.MutableIssue;

MutableIssue mutableIssue = (MutableIssue) issue;
String subject=issue.summary;            //gets the summary
int indexfind;                           //Help Index to Find "Priority:"
indexfind=subject.indexOf("Priority:");  //finds 'P' of "Priority:"
String Prio=subject.charAt(indexfind+9); // finds the number of summary

switch (Prio){ 
    case "1": mutableIssue.setPriorityId("2"); //set prio Critical 
              break; 
    case "2": mutableIssue.setPriorityId("3"); //set prio high 
              break; 
    case "3": mutableIssue.setPriorityId("4"); //set Prio Moderate 
              break; 
    case "4": mutableIssue.setPriorityId("5"); //set Prio Low 
              break; 
    default:  mutableIssue.setPriorityId("5"); //sets to default od Low 
              break; 
}

The Script runner does not throw in exception but the intended use is not given. Couldt you please help me resolve this issue?

[Joshua Yamdogo @ Adaptavist · Accepted solution]

Answered on product support:

import com.atlassian.jira.issue.MutableIssue
import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.event.type.EventDispatchOption
def issue = issue as MutableIssue
String subject = issue.summary //gets the summary
int indexfind  //Help Index to Find "Priority:"
indexfind = subject.indexOf("Priority:")   //finds 'P' of "Priority:"
String Prio = subject.charAt(indexfind+9)  // finds the number of summary
switch (Prio)
{
    case "1":
        issue.setPriorityId("2") //set prio Critical
        break
    case "2":
        issue.setPriorityId("3") //set prio high
        break
    case "3":
        issue.setPriorityId("4") //set Prio Moderate
        break
    case "4":
        issue.setPriorityId("5") //set Prio Low
        break
    default:
        issue.setPriorityId("5") //sets to default od Low 
        break
}
ComponentAccessor.getIssueManager().updateIssue(ComponentAccessor.getJiraAuthenticationContext().getLoggedInUser(), issue, EventDispatchOption.DO_NOT_DISPATCH, false);