epicLink

import com.atlassian.jira.component.ComponentAccessor;
import com.atlassian.jira.issue.CustomFieldManager;
import com.atlassian.jira.issue.fields.CustomField;
import com.atlassian.jira.issue.Issue;
CustomFieldManager customFieldManager = ComponentAccessor.getCustomFieldManager();
CustomField epicLink = customFieldManager.getCustomFieldObjectByName('Epic Link');
CustomField epicName = customFieldManager.getCustomFieldObjectByName('Epic Name');
//This is where we store the issue that is linked to the epic.
Issue issue_linked_to_epic
/* determine if this is an epic, if so, return the epic link name */
if (issue.issueTypeObject.name == "Epic"){
	return issue.getCustomFieldValue(epicName)
}
/*determine if this is a subTaskIssueTypes(), if so, set the parent to the issue linked to the epic */
Issue issueParent = issue.getParentObject()
if (issueParent == null){
	issue_linked_to_epic = issue
} else {
	issue_linked_to_epic = issueParent
}
/* get epic link */
Issue epic = (Issue) issue_linked_to_epic.getCustomFieldValue(epicLink)
if (epic == null){
	return null
}
String epicNameString = epic.getCustomFieldValue(epicName)
return epicNameString