JoinStateWatermarkPredicate Contract (Sealed Trait)

JoinStateWatermarkPredicate is the abstraction of join state watermark predicates that are described by a Catalyst expression and desc.

JoinStateWatermarkPredicate is used to create a OneSideHashJoiner (and JoinStateWatermarkPredicates).

Table 1. JoinStateWatermarkPredicate Contract
Method	Description
`desc`	`desc: String` Used exclusively for the textual representation
`expr`	`expr: Expression` A Catalyst `Expression` Used for the textual representation and a JoinStateWatermarkPredicates (for StreamingSymmetricHashJoinExec physical operator)

Table 2. JoinStateWatermarkPredicates
JoinStateWatermarkPredicate	Description
JoinStateKeyWatermarkPredicate	Watermark predicate on state keys (i.e. when the streaming watermark is defined either on the left or right join keys) Created when `StreamingSymmetricHashJoinHelper` utility is requested for a JoinStateWatermarkPredicates for the left and right side of a stream-stream join (when `IncrementalExecution` is requested to optimize a query plan with a StreamingSymmetricHashJoinExec physical operator) Used when `OneSideHashJoiner` is requested for the stateKeyWatermarkPredicateFunc and then to remove an old state
JoinStateValueWatermarkPredicate	Watermark predicate on state values

Note	`JoinStateWatermarkPredicate` is a Scala sealed trait which means that all the implementations are in the same compilation unit (a single file).

toString: String

Note	`toString` is part of the java.lang.Object contract for the string representation of the object.

toString uses the desc and expr for the string representation:

[desc]: [expr]

JoinStateWatermarkPredicate