Question

当前的Hazelcast Jet 0.6.1代码示例演示了基于单个字段的聚合（例如，自动收报机）。

这是一个参考。

\ code-samples \ streaming \ stock-exchange \ src \ main \ java \ StockExchange.java

如何将其扩展为多个，如ticker，traderId等。

以下是StockExchange.java

的当前示例代码

 private static Pipeline buildPipeline() {
    Pipeline p = Pipeline.create();

    p.drawFrom(Sources.<Trade, Integer, Trade>mapJournal(TRADES_MAP_NAME,
            alwaysTrue(), EventJournalMapEvent::getNewValue, START_FROM_CURRENT))
     .addTimestamps(Trade::getTime, 3000)
     .groupingKey(Trade::getTicker)
     .window(WindowDefinition.sliding(SLIDING_WINDOW_LENGTH_MILLIS, SLIDE_STEP_MILLIS))
     .aggregate(counting(),
             (winStart, winEnd, key, result) -> String.format("%s %5s %4d", toLocalTime(winEnd), key, result))
     .drainTo(Sinks.logger());

    return p;
}

Answer 1

对于自动收报机和traderId你可以使用：

<nav class="navbar navbar-expand-sm navbar-dark bg-dark">

  <div class="collapse navbar-collapse justify-content-center d-flex">
    <a class="navbar-brand">WIDE-LOGO-TEXT</a>

    <ul class="navbar-nav">
      <li class="nav-item">
        <a class="nav-link">Home</a>
      </li>
      <li class="nav-item">
        <a class="nav-link">Gallery</a>
      </li>
      <li class="nav-item">
        <a class="nav-link">Services</a>
      </li>
      <li class="nav-item">
        <a class="nav-link">Contact Us</a>
      </li>
    </ul>

  </div>
</nav>

<!-- Second NavBar: --> 

<nav class="navbar navbar-expand-sm navbar-dark bg-dark">

  <div class="collapse navbar-collapse d-flex">
    <a class="navbar-brand">WIDE-LOGO-TEXT</a>

    <ul class="navbar-nav" style="margin: 0 auto;">
      <li class="nav-item">
        <a class="nav-link">Home</a>
      </li>
      <li class="nav-item">
        <a class="nav-link">Gallery</a>
      </li>
      <li class="nav-item">
        <a class="nav-link">Services</a>
      </li>
      <li class="nav-item">
        <a class="nav-link">Contact Us</a>
      </li>
    </ul>

  </div>
</nav>

通常，密钥可以通过正确实现.groupingKey(trade -> Tuple2.tuple2(trade.getTicker(), trade.getTraderId()))和equals的任何内容来实现。 hashCode是两个值的通用容器。

Answer 2

我们还可以为分组提供逗号分隔的键。

.aggregate(AggregateOperations.groupingBy(data -> {
    StringBuilder stringBuilder = new StringBuilder();
    stringBuilder.append(StringUtils.defaultString(data.getSource1().get(dataValue) + "", "")).append(",");
    return stringBuilder.substring(0, stringBuilder.toString().length() - 1); 
}));

Hazelcast Jet 0.6.1-多个领域的聚合

2 个答案: