Flink：找不到合适的方法

我正在尝试在Flink的DataStream上应用每个窗口的功能。以下是我的代码

DataStream> data = ...
DataStream> freqCityChangeTransactions = data

.keyBy(0)
.timeWindow(Time.seconds(5))
.process(new MyProcessWindowFunction());

以下是我对MyProcessWindowFunction的实现

public static class MyProcessWindowFunction
extends ProcessWindowFunction, Tuple2, String, TimeWindow> {

public void process(String key,

        Context context,
        Iterable<Tuple2<String, String>> input,
        Collector<Tuple2<String, String>> out) {
    // Do something ...
}

}
但是，当我尝试通过maven编译上面的代码时，我收到以下错误

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.6.1:compile (default-compile) on project flink-examples: Compilation failure
[ERROR] /Users/furqan/Workspace/flink/src/main/java/com/baig/bank/Bank.java:[120,13] no suitable method found for process(com.baig.Bank.MyProcessWindowFunction)
[ERROR] method org.apache.flink.streaming.api.datastream.WindowedStream.process(org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction,R,org.apache.flink.api.java.tuple.Tuple,org.apache.flink.streaming.api.windowing.windows.TimeWindow>) is not applicable
ERROR R
ERROR)
[ERROR] method org.apache.flink.streaming.api.datastream.WindowedStream.process(org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction,R,org.apache.flink.api.java.tuple.Tuple,org.apache.flink.streaming.api.windowing.windows.TimeWindow>,org.apache.flink.api.common.typeinfo.TypeInformation) is not applicable
ERROR R
ERROR)
我正在使用Apache Flink 1.5.1版并在Mac上使用maven3编译Java代码。