AbstractPQLQuery.java 文件源码

protected Set<PQLTask> interpretDifference(ParseTree tree) {
    ParseTree child = tree.getChild(2);
    int ruleIndex = ((RuleNode)child).getRuleContext().getRuleIndex();

    Set<PQLTask> set1 = this.interpretTasks(tree.getChild(0));
    Set<PQLTask> set2 = new HashSet<PQLTask>();

    switch (ruleIndex) {
        case PQLParser.RULE_tasks:
            set2 = interpretTasks(child);
            break;
        case PQLParser.RULE_difference:
            set2 = interpretDifference(child);
            break;
       }

    set1.removeAll(set2);

    return set1;
}