[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.

Public Methods

  NameDescription
AddView
Add a view to the viewable object.
(Inherited from ViewSupport.)
AttachesTo
Return null if the view will accept being attached to a particular object.
(Overrides .AttachesTo(Viewable).)
Equals (Inherited from Object.)
GetEnumerator
Returns an enumerator that iterates through the collection.
(Overrides .GetEnumerator().)
GetHashCode (Inherited from Object.)
GetType (Inherited from Object.)
GetViews
Returns all added views.
(Inherited from ViewSupport.)
RemoveView
Remove a view.
(Inherited from ViewSupport.)
ToString
Returns a String that represents the current Object.
(Overrides .ToString().)
Update
Notify that data has been added or removed from the Viewable parent. The last object in the newData array of objects would be the newest object added to the parent view. The first object of the oldData array of objects would be the oldest object removed from the parent view.

If the call to update contains new (inserted) data, then the first argument will be a non-empty list and the second will be empty. Similarly, if the call is a notification of deleted data, then the first argument will be empty and the second will be non-empty. Either the newData or oldData will be non-null. This method won't be called with both arguments being null, but either one could be null. The same is true for zero-length arrays. Either newData or oldData will be non-empty. If both are non-empty, then the update is a modification notification.

When update() is called on a view by the parent object, the data in newData will be in the collection of the parent, and its data structures will be arranged to reflect that. The data in oldData will not be in the parent's data structures, and any access to the parent will indicate that that data is no longer there.

(Overrides .Update(EventBean[](), EventBean[]()).)

Protected Methods

  NameDescription
Finalize (Inherited from Object.)
MemberwiseClone (Inherited from Object.)

Protected Fields

  NameDescription
parent
Parent viewable to this view - directly accessible by subclasses.
(Inherited from ViewSupport.)

Public Constructors

  NameDescription
UniqueByPropertyViewNewOverloaded.

Public Properties

  NameDescription
EventType
Provides metadata information about the type of object the event collection contains.
(Overrides .EventType.)
HasViews
Test is there are any views to the Viewable.
(Inherited from ViewSupport.)
Id
Gets the unique id for the view
(Inherited from ViewSupport.)
Parent
Gets or sets the View's parent Viewable.
(Overrides .Parent.)
UniqueFieldName
Gets or sets the name of the field supplying the unique value to keep the most recent record for.

Explicit Interface Implementations

  NameDescription
Explicit interface implemetationIEnumerable.System.Collections.IEnumerable.GetEnumerator
Returns an enumerator that iterates through a collection.
(Inherited from ViewSupport.)