Apache Flink + CEP - 檢測相同的事件

Question

我想檢測共享相同屬性的事件。假設我有一個簡單的例子類：

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

假設有下面的流：

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

然後我想檢測雙「A」記錄。這可能嗎？我現在有這樣的：

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

Answer 1

我想你要定義什麼是事件檢測，你嘗試過這樣的：

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()