flink aggregate方法报错

Question

 DataStream<ItemViewCount> windowAggStream = dataStream
                .filter(data -> "pv".equals(data.getBehavior()))    // 过滤pv行为
                .keyBy("itemId")    // 按商品ID分组
                .timeWindow(Time.hours(1), Time.minutes(5))    // 开滑窗
                .aggregate(new ItemCountAgg(), new WindowItemCountResult());

public static class ItemCountAgg implements AggregateFunction<UserBehavior, Long, Long> {
        @Override
        public Long createAccumulator() {
            return 0L;
        }

        @Override
        public Long add(UserBehavior value, Long accumulator) {
            return accumulator + 1;
        }

        @Override
        public Long getResult(Long accumulator) {
            return accumulator;
        }

        @Override
        public Long merge(Long a, Long b) {
            return a + b;
        }
    }

public static class WindowItemCountResult implements WindowFunction<Long, ItemViewCount, Tuple, TimeWindow> {
        @Override
        public void apply(Tuple tuple, TimeWindow window, Iterable<Long> input, Collector<ItemViewCount> out) throws Exception {
            Long itemId = tuple.getField(0);
            Long windowEnd = window.getEnd();
            Long count = input.iterator().next();
            out.collect(new ItemViewCount(itemId, windowEnd, count));
        }
    }

上面是截取的代码，运行报错:
Error:(62, 17) java: 对于aggregate(com.zqs.flink.project.hotitemanalysis.HotItems.ItemCountAgg,com.zqs.flink.project.hotitemanalysis.HotItems.WindowItemCountResult), 找不到合适的方法
方法 org.apache.flink.streaming.api.datastream.WindowedStream.<ACC,R>aggregate(org.apache.flink.api.common.functions.AggregateFunction<com.zqs.flink.project.hotitemanalysis.beans.UserBehavior,ACC,R>)不适用
(无法推断类型变量 ACC,R
(实际参数列表和形式参数列表长度不同))