com.espertech.esper.view.ext
Class SortWindowView

java.lang.Object
  com.espertech.esper.view.ViewSupport
      com.espertech.esper.view.ext.SortWindowView

All Implemented Interfaces:

CloneableView, DataWindowView, EventCollection, GroupableView, View, Viewable, ViewDataVisitable, java.lang.Iterable<EventBean>

public class SortWindowView
extends ViewSupport
implements DataWindowView, CloneableView

Window sorting by values in the specified field extending a specified number of elements from the lowest value up or the highest value down. The view accepts 3 parameters. The first parameter is the field name to get the values to sort for, the second parameter defines whether to sort ascending or descending, the third parameter is the number of elements to keep in the sorted list. The type of the field to be sorted in the event must implement the Comparable interface. The natural order in which events arrived is used as the second sorting criteria. Thus should events arrive with equal sort values the oldest event leaves the sort window first. Old values removed from a prior view are removed from the sort view.

Field Summary

protected AgentInstanceViewFactoryChainContext	agentInstanceViewFactoryContext
protected int	eventCount
protected ExprEvaluator[]	sortCriteriaEvaluators
protected java.util.TreeMap<java.lang.Object,java.lang.Object>	sortedEvents

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

EMPTY_VIEW_ARRAY, parent

Constructor Summary

SortWindowView(SortWindowViewFactory sortWindowViewFactory, ExprNode[] sortCriteriaExpressions, ExprEvaluator[] sortCriteriaEvaluators, boolean[] descendingValues, int sortWindowSize, IStreamSortRankRandomAccess optionalSortedRandomAccess, boolean isSortUsingCollator, AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)
Ctor.

Method Summary

View	cloneView() Duplicates the view.
EventType	getEventType() Provides metadata information about the type of object the event collection contains.
protected boolean[]	getIsDescendingValues() Returns the flags indicating whether to sort in descending order on each property.
protected ExprNode[]	getSortCriteriaExpressions() Returns the field names supplying the values to sort by.
protected java.lang.Object	getSortValues(EventBean theEvent)
protected int	getSortWindowSize() Returns the number of elements kept by the sort window.
ViewFactory	getViewFactory()
void	internalHandleAdd(java.lang.Object sortValues, EventBean newDataItem)
void	internalHandleRemoved(java.lang.Object sortValues, EventBean oldDataItem)
boolean	isEmpty() True to indicate the sort window is empty, or false if not empty.
java.util.Iterator<EventBean>	iterator() Allows iteration through all elements in this event collection.
java.lang.String	toString()
void	update(EventBean[] newData, EventBean[] oldData) Notify that data has been added or removed from the Viewable parent.
void	visitView(ViewDataVisitor viewDataVisitor)

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, wait, wait, wait

Methods inherited from interface com.espertech.esper.view.View

getParent, setParent

Methods inherited from interface com.espertech.esper.view.Viewable

addView, getViews, hasViews, removeAllViews, removeView

Field Detail

sortCriteriaEvaluators

protected final ExprEvaluator[] sortCriteriaEvaluators

agentInstanceViewFactoryContext

protected final AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext

sortedEvents

protected java.util.TreeMap<java.lang.Object,java.lang.Object> sortedEvents

eventCount

protected int eventCount

Constructor Detail

SortWindowView

public SortWindowView(SortWindowViewFactory sortWindowViewFactory,
                      ExprNode[] sortCriteriaExpressions,
                      ExprEvaluator[] sortCriteriaEvaluators,
                      boolean[] descendingValues,
                      int sortWindowSize,
                      IStreamSortRankRandomAccess optionalSortedRandomAccess,
                      boolean isSortUsingCollator,
                      AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)

Ctor.

Parameters:

sortCriteriaExpressions - is the event property names to sort

descendingValues - indicates whether to sort ascending or descending for each field

sortWindowSize - is the window size

optionalSortedRandomAccess - is the friend class handling the random access, if required by expressions

sortWindowViewFactory - for copying this view in a group-by

isSortUsingCollator - for string value sorting using compare or Collator

Method Detail

getSortCriteriaExpressions

protected final ExprNode[] getSortCriteriaExpressions()

Returns the field names supplying the values to sort by.

Returns:

field names to sort by

getIsDescendingValues

protected final boolean[] getIsDescendingValues()

Returns the flags indicating whether to sort in descending order on each property.

Returns:

the isDescending value for each sort property

getSortWindowSize

protected final int getSortWindowSize()

Returns the number of elements kept by the sort window.

Returns:

size of window

cloneView

public View cloneView()

Description copied from interface: CloneableView

Duplicates the view.

Expected to return a same view in initialized state for grouping.

Specified by:

cloneView in interface CloneableView

getEventType

public final 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

update

public final 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

internalHandleAdd

public void internalHandleAdd(java.lang.Object sortValues,
                              EventBean newDataItem)

internalHandleRemoved

public void internalHandleRemoved(java.lang.Object sortValues,
                                  EventBean oldDataItem)

iterator

public final 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.

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object

getSortValues

protected java.lang.Object getSortValues(EventBean theEvent)

isEmpty

public boolean isEmpty()

True to indicate the sort window is empty, or false if not empty.

Returns:

true if empty sort window

visitView

public void visitView(ViewDataVisitor viewDataVisitor)

Specified by:

visitView in interface ViewDataVisitable

getViewFactory

public ViewFactory getViewFactory()

Specified by:

getViewFactory in interface GroupableView