[This topic is pre-release documentation and is subject to change in future releases. Blank topics are included as placeholders.]
This view includes only the most recent among events having the same value for the specified field.
The view accepts the field name as parameter from which the unique values are obtained.
For example, a trade's symbol could be used as a unique value.
In this example, the first trade for symbol IBM would be posted as new data to child views.
When the second trade for symbol IBM arrives the second trade is posted as new data to child views,
and the first trade is posted as old data.
Should more than one trades for symbol IBM arrive at the same time (like when batched)
then the child view will get all new events in newData and all new events in oldData minus the most recent event.
When the current new event arrives as old data, the the current unique event gets thrown away and
posted as old data to child views.
Iteration through the views data shows only the most recent events received for the unique value in the order
that events arrived in.
The type of the field returning the unique value can be any type but should override equals and hashCode()
as the type plays the role of a key in a map storing unique values.
The following tables list the members exposed by the UniqueByPropertyView type.
Protected Fields
Name | Description | |
---|---|---|
![]() | parent |
Parent viewable to this view - directly accessible by subclasses.
(Inherited from ViewSupport.) |