Apache Flink + CEP -检测相同的事件

Question

我想要检测具有相同属性的事件。假设我有一个简单的case类：

case class Record(name: String, value: Int)

假设有以下流：

Record("A", 1)
Record("B", 2)
Record("A", 3)
Record("C", 4)

然后我想要检测双"A“记录。这个是可能的吗？我现在有了这个：

val start: Pattern[Record, _] = myStream
.begin("first")
.followedBy("second").where(previous_record.name == _.name)

Answer 1

我认为你正在定义什么是事件检测，你有没有尝试过这个：

val start: Pattern[Record, _] = myStream
   .begin("first").where(name == "A")
   .followedBy("second").where(name == "A")

更新：例如：

val patternIG: Pattern[(String,String), _] = Pattern.begin[String,String)]("start").where(_.name == "Ignition").where(_.ac == "ON").next("end").where(_.name == "Door").where(_.ac == "ON")
val patternStream: PatternStream[(String,String)] = CEP.pattern(mystream, patternIG)
def selectFn(pattern : mutable.Map[String,(String,String)]): String = {
val startEvent = pattern.get("start").get
val endEvent = pattern.get("end").get
  "ALERT Door Open"
}
val patternStreamSelected = patternStream.select(selectFn(_)).print()