com.espertech.esper.view

Class ViewServiceImpl

java.lang.Object

com.espertech.esper.view.ViewServiceImpl

All Implemented Interfaces:

ViewService

public final class ViewServiceImpl
extends Object
implements ViewService

Implementation of the view evaluation service business interface.

Constructor Summary

Constructors

Constructor and Description
ViewServiceImpl() Ctor.

Method Summary

Modifier and Type	Method and Description
ViewFactoryChain	createFactories(int streamNum, EventType parentEventType, ViewSpec[] viewSpecDefinitions, StreamSpecOptions options, StatementContext context, boolean isSubquery, int subqueryNumber) Returns a chain of view factories that can be used to obtain the final event type, and that can later be used to actually create the chain of views or reuse existing views.
ViewServiceCreateResult	createViews(Viewable eventStreamViewable, List<ViewFactory> viewFactories, AgentInstanceViewFactoryChainContext viewFactoryChainContext, boolean hasPreviousNode) Creates the views given a chain of view factories.
void	remove(EventStream eventStream, Viewable viewToRemove) Removes a view discoupling the view and any of it's parent views up the tree to the last shared parent view.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ViewServiceImpl

public ViewServiceImpl()

Ctor.

Method Detail

createFactories

public ViewFactoryChain createFactories(int streamNum,
                                        EventType parentEventType,
                                        ViewSpec[] viewSpecDefinitions,
                                        StreamSpecOptions options,
                                        StatementContext context,
                                        boolean isSubquery,
                                        int subqueryNumber)
                                 throws ViewProcessingException

Description copied from interface: ViewService

Returns a chain of view factories that can be used to obtain the final event type, and that can later be used to actually create the chain of views or reuse existing views.

Does not actually hook up the view factories or views against the event stream, but creates view factories and sets parameters on each view factory as supplied. Determines if view factories are compatible in the chain via the attach method.

Specified by:

createFactories in interface ViewService

Parameters:

streamNum - - the stream number starting at zero, a join would have N streams

parentEventType - - is the event type of the event stream that originates the raw events

viewSpecDefinitions - - the specification for each view factory in the chain to be created

options - - stream options such as unidirectional, retain-union etc

context - - dependent services

isSubquery - subquery indicator

subqueryNumber - subquery num

Returns:

chain of view factories

Throws:

ViewProcessingException - thrown if a view factory doesn't take parameters as supplied, or cannot hook onto it's parent view or event stream

createViews

public ViewServiceCreateResult createViews(Viewable eventStreamViewable,
                                           List<ViewFactory> viewFactories,
                                           AgentInstanceViewFactoryChainContext viewFactoryChainContext,
                                           boolean hasPreviousNode)

Description copied from interface: ViewService

Creates the views given a chain of view factories.

Attempts to reuse compatible views under then parent event stream viewable as indicated by each view factories reuse method.

Specified by:

createViews in interface ViewService

Parameters:

eventStreamViewable - is the event stream to hook into

viewFactories - defines the list of view factorys to call makeView or canReuse on

viewFactoryChainContext - provides services

hasPreviousNode - indicator whether previous-expr

Returns:

last viewable in chain, or the eventStreamViewable if no view factories are supplied

remove

public void remove(EventStream eventStream,
                   Viewable viewToRemove)

Description copied from interface: ViewService

Removes a view discoupling the view and any of it's parent views up the tree to the last shared parent view.

Specified by:

remove in interface ViewService

Parameters:

eventStream - - the event stream that originates the raw events

viewToRemove - - the view (should be the last in a chain) to remove