com.espertech.esper.epl.variable
Class CreateVariableView

java.lang.Object
  com.espertech.esper.view.ViewSupport
      com.espertech.esper.epl.variable.CreateVariableView

All Implemented Interfaces:

VariableChangeCallback, EventCollection, View, Viewable, java.lang.Iterable<EventBean>

public class CreateVariableView
extends ViewSupport
implements VariableChangeCallback

View for handling create-variable syntax.

The view posts to listeners when a variable changes, if it has subviews.

The view returns the current variable value for the iterator.

The event type for such posted events is a single field Map with the variable value.

Field Summary

Fields inherited from class com.espertech.esper.view.ViewSupport

EMPTY_VIEW_ARRAY, parent

Constructor Summary

CreateVariableView(java.lang.String statementId, EventAdapterService eventAdapterService, VariableService variableService, java.lang.String variableName, StatementResultService statementResultService)
Ctor.

Method Summary

EventType	getEventType() Provides metadata information about the type of object the event collection contains.
static EventType	getEventType(java.lang.String statementId, EventAdapterService eventAdapterService, VariableMetaData variableMetaData)
java.util.Iterator<EventBean>	iterator() Allows iteration through all elements in this event collection.
void	update(EventBean[] newData, EventBean[] oldData) Notify that data has been added or removed from the Viewable parent.
void	update(java.lang.Object newValue, java.lang.Object oldValue) Indicate a change in variable value.

Methods inherited from class com.espertech.esper.view.ViewSupport

addView, addView, dumpChildViews, dumpUpdateParams, dumpUpdateParams, findDescendent, findViewIndex, getParent, getViews, hasViews, removeAllViews, removeView, removeView, setParent, updateChildren, updateChildren

Methods inherited from class java.lang.Object

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

Constructor Detail

CreateVariableView

public CreateVariableView(java.lang.String statementId,
                          EventAdapterService eventAdapterService,
                          VariableService variableService,
                          java.lang.String variableName,
                          StatementResultService statementResultService)

Ctor.

Parameters:

eventAdapterService - for creating events

variableService - for looking up variables

variableName - is the name of the variable to create

statementResultService - for coordinating on whether insert and remove stream events should be posted

Method Detail

getEventType

public static EventType getEventType(java.lang.String statementId,
                                     EventAdapterService eventAdapterService,
                                     VariableMetaData variableMetaData)

update

public void update(java.lang.Object newValue,
                   java.lang.Object oldValue)

Description copied from interface: VariableChangeCallback

Indicate a change in variable value.

Specified by:

update in interface VariableChangeCallback

Parameters:

newValue - new value

oldValue - old value

update

public void update(EventBean[] newData,
                   EventBean[] oldData)

Description copied from interface: View

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.

Specified by:

update in interface View

Parameters:

newData - is the new data that has been added to the parent view

oldData - is the old data that has been removed from the parent view

getEventType

public EventType getEventType()

Description copied from interface: EventCollection

Provides metadata information about the type of object the event collection contains.

Specified by:

getEventType in interface EventCollection

Returns:

metadata for the objects in the collection

iterator

public java.util.Iterator<EventBean> iterator()

Description copied from interface: EventCollection

Allows iteration through all elements in this event collection. The iterator will return the elements in the collection in their natural order, or, if there is no natural ordering, in some unpredictable order.

Specified by:

iterator in interface EventCollection

Specified by:

iterator in interface java.lang.Iterable<EventBean>

Returns:

an iterator which will go through all current elements in the collection.