getValues()

public final List<QueryLiteral> getValues(
        final QueryCreationContext queryCreationCtx,
        final FunctionOperand operand,
        final TerminalClause terminalClause) {

    LOG.debug("Calling getValues of " + this.getClass().toString() + "on the object " + this.toString());
    List<QueryLiteral> literals = Collections.emptyList();
    String cache_key = terminalClause.getName();

    //here I use the cache as described in https://jira.atlassian.com/browse/JRA-22256
    if (!cache.containsKey(cache_key)) {
        // initialise fields if first use
        if (taLink == null) {
            taLink = new TeamAssistDatabaseLink(); // This is a link to an external Oracle DB
            final CustomFieldManager cfManager = ComponentManager.getInstance().getCustomFieldManager();
            customField = cfManager.getCustomFieldObject(TeamAssistProperties.customfieldID());
        }

        // get the options associated with the custom field
        final JiraContextNode contextNode = GlobalIssueContext.getInstance();
        final List<Option> options = (List<Option>)customField.getOptions(null, contextNode).getRootOptions();

        // build a list of "cases" (kind of customfield) as query literals
        literals = new ArrayList<QueryLiteral>(options.size());
        for (Option option : options) {
            final String taId = option.getValue();
            if (taLink.isCase(taId)) {
                LOG.debug("Adding " + taId);
                literals.add(new QueryLiteral(operand, taId));
            }

        }
        cache.put(cache_key, literals);
        LOG.debug("Create an instance into the cache with key: " + cache_key);
    } else {
        literals = cache.get(cache_key);
        LOG.debug("Get an instance from the cache with key: " + cache_key);
    }

    LOG.debug("EXITING: " + literals.size());
    return literals;
}