public class GroupByViewImpl extends ViewSupport implements CloneableView, GroupByView
The view takes a single parameter which is the field name returning the key value to group.
This view can, for example, be used to calculate the average price per symbol for a list of symbols.
The view treats its child views and their child views as prototypes. It dynamically instantiates copies of each child view and their child views, and the child view's child views as so on. When there are no more child views or the special merge view is encountered, it ends. The view installs a special merge view unto each leaf child view that merges the value key that was grouped by back into the stream using the group-by field name.
| Modifier and Type | Field and Description |
|---|---|
protected AgentInstanceViewFactoryChainContext |
agentInstanceContext |
protected String[] |
propertyNames |
protected Map<Object,Object> |
subViewsPerKey |
static String |
VIEWNAME |
EMPTY_VIEW_ARRAY, parent| Constructor and Description |
|---|
GroupByViewImpl(AgentInstanceViewFactoryChainContext agentInstanceContext,
ExprNode[] criteriaExpressions,
ExprEvaluator[] criteriaEvaluators)
Constructor.
|
| Modifier and Type | Method and Description |
|---|---|
protected static Object |
addUpgradeToDequeIfPopulated(Object holder,
EventBean theEvent) |
View |
cloneView()
Duplicates the view.
|
protected static EventBean[] |
convertToArray(Object eventOrDeque) |
ExprNode[] |
getCriteriaExpressions()
Returns the field name that provides the key valie by which to group by.
|
EventType |
getEventType()
Provides metadata information about the type of object the event collection contains.
|
Iterator<EventBean> |
iterator()
Allows iteration through all elements in this event collection.
|
static Object |
makeSubViews(GroupByView groupView,
String[] propertyNames,
Object groupByValues,
AgentInstanceViewFactoryChainContext agentInstanceContext)
Instantiate subviews for the given group view and the given key value to group-by.
|
boolean |
removeView(View view)
Remove a view.
|
String |
toString() |
void |
update(EventBean[] newData,
EventBean[] oldData)
Notify that data has been added or removed from the Viewable parent.
|
protected static void |
updateChildViews(Object subViews,
EventBean[] newData,
EventBean[] oldData) |
static void |
visitView(ViewDataVisitorContained viewDataVisitor,
Object groupkey,
Object subviewHolder) |
void |
visitViewContainer(ViewDataVisitorContained viewDataVisitor) |
addView, addView, dumpChildViews, dumpUpdateParams, dumpUpdateParams, findDescendent, findViewIndex, getParent, getViews, hasViews, removeAllViews, removeView, setParent, updateChildren, updateChildrenclone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitaddView, getViews, hasViews, removeAllViewsforEach, spliteratorpublic static final String VIEWNAME
protected final AgentInstanceViewFactoryChainContext agentInstanceContext
protected String[] propertyNames
public GroupByViewImpl(AgentInstanceViewFactoryChainContext agentInstanceContext, ExprNode[] criteriaExpressions, ExprEvaluator[] criteriaEvaluators)
criteriaExpressions - is the fields from which to pull the values to group byagentInstanceContext - contains required view servicescriteriaEvaluators - evaluatorspublic View cloneView()
CloneableViewExpected to return a same view in initialized state for grouping.
cloneView in interface CloneableViewpublic ExprNode[] getCriteriaExpressions()
getCriteriaExpressions in interface GroupByViewpublic final EventType getEventType()
EventCollectiongetEventType in interface EventCollectionpublic final void update(EventBean[] newData, EventBean[] oldData)
ViewIf 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.
public final Iterator<EventBean> iterator()
EventCollectioniterator in interface EventCollectioniterator in interface Iterable<EventBean>public static Object makeSubViews(GroupByView groupView, String[] propertyNames, Object groupByValues, AgentInstanceViewFactoryChainContext agentInstanceContext)
groupView - is the parent view for which to copy subviews forgroupByValues - is the key values to group-byagentInstanceContext - is the view services that sub-views may needpropertyNames - names of expressions or propertiespublic void visitViewContainer(ViewDataVisitorContained viewDataVisitor)
visitViewContainer in interface ViewDataVisitableContainerpublic static void visitView(ViewDataVisitorContained viewDataVisitor, Object groupkey, Object subviewHolder)
public boolean removeView(View view)
ViewableremoveView in interface ViewableremoveView in class ViewSupportview - to removeprotected static void updateChildViews(Object subViews, EventBean[] newData, EventBean[] oldData)
protected static Object addUpgradeToDequeIfPopulated(Object holder, EventBean theEvent)