com.espertech.esper.view

Interface ViewFactory

All Known Subinterfaces:

AsymetricDataWindowViewFactory, DataWindowViewFactory

All Known Implementing Classes:

CorrelationViewFactory, EventRowRegexNFAViewFactory, ExpressionBatchViewFactory, ExpressionViewFactoryBase, ExpressionWindowViewFactory, ExternallyTimedBatchViewFactory, ExternallyTimedWindowViewFactory, FirstElementViewFactory, FirstLengthWindowViewFactory, FirstTimeViewFactory, FirstUniqueByPropertyViewFactory, GroupByViewFactory, IntersectViewFactory, KeepAllViewFactory, LastElementViewFactory, LengthBatchViewFactory, LengthWindowViewFactory, MergeViewFactory, NoopViewFactory, PriorEventViewFactory, RankWindowViewFactory, RegressionLinestViewFactory, SizeViewFactory, SortWindowViewFactory, TimeAccumViewFactory, TimeBatchViewFactory, TimeLengthBatchViewFactory, TimeOrderViewFactory, TimeToLiveViewFactory, TimeWindowViewFactory, UnionViewFactory, UniqueByPropertyViewFactory, UnivariateStatisticsViewFactory, ViewFactorySupport, VirtualDWViewFactoryImpl, WeightedAverageViewFactory

public interface ViewFactory

Factory interface for a factory responsible for creating a View instance and for determining if an existing view meets requirements.

Method Summary

Modifier and Type	Method and Description
void	attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List<ViewFactory> parentViewFactories) Attaches the factory to a parent event type such that the factory can validate attach requirements and determine an event type for resulting views.
boolean	canReuse(View view, AgentInstanceContext agentInstanceContext) Determines if the given view could be used instead of creating a new view, requires the view factory to compare view type, parameters and other capabilities provided.
EventType	getEventType() Returns the event type that the view that is created by the view factory would create for events posted by the view.
String	getViewName() Returns the name of the view, not namespace+name but readable name.
View	makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext) Create a new view.
void	setViewParameters(ViewFactoryContext viewFactoryContext, List<ExprNode> viewParameters) Indicates user EPL query view parameters to the view factory.

Method Detail

setViewParameters

void setViewParameters(ViewFactoryContext viewFactoryContext,
                       List<ExprNode> viewParameters)
                throws ViewParameterException

Indicates user EPL query view parameters to the view factory.

Parameters:

viewFactoryContext - supplied context information for the view factory

viewParameters - is the objects representing the view parameters

Throws:

ViewParameterException - if the parameters don't match view parameter needs

attach

void attach(EventType parentEventType,
            StatementContext statementContext,
            ViewFactory optionalParentFactory,
            List<ViewFactory> parentViewFactories)
     throws ViewParameterException

Attaches the factory to a parent event type such that the factory can validate attach requirements and determine an event type for resulting views.

Parameters:

parentEventType - is the parent event stream's or view factory's event type

statementContext - contains the services needed for creating a new event type

optionalParentFactory - is null when there is no parent view factory, or contains the parent view factory

parentViewFactories - is a list of all the parent view factories or empty list if there are none

Throws:

ViewParameterException - is thrown to indicate that this view factories's view would not play with the parent view factories view

makeView

View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)

Create a new view.

Parameters:

agentInstanceViewFactoryContext - context

Returns:

view

getEventType

EventType getEventType()

Returns the event type that the view that is created by the view factory would create for events posted by the view.

Returns:

event type of view's created by the view factory

canReuse

boolean canReuse(View view,
                 AgentInstanceContext agentInstanceContext)

Determines if the given view could be used instead of creating a new view, requires the view factory to compare view type, parameters and other capabilities provided.

Parameters:

view - is the candidate view to compare to

agentInstanceContext - agent instance context

Returns:

true if the given view can be reused instead of creating a new view, or false to indicate the view is not right for reuse

getViewName

String getViewName()

Returns the name of the view, not namespace+name but readable name.

Returns:

readable name