Package org.apache.cassandra.db.view

Class ViewUpdateGenerator

java.lang.Object

org.apache.cassandra.db.view.ViewUpdateGenerator

public class ViewUpdateGenerator
extends Object

Creates the updates to apply to a view given the existing rows in the base table and the updates that we're applying to them (this handles updates on a single partition only). This class is used by passing the updates made to the base table to addBaseTableUpdate(org.apache.cassandra.db.rows.Row, org.apache.cassandra.db.rows.Row) and calling generateViewUpdates() once all updates have been handled to get the resulting view mutations.

Constructor Summary

Constructors

Constructor	Description
ViewUpdateGenerator(View view, DecoratedKey basePartitionKey, long nowInSec)	Creates a new ViewUpdateBuilder.

Method Summary

Modifier and Type	Method	Description
void	addBaseTableUpdate(Row existingBaseRow, Row mergedBaseRow)	Adds to this generator the updates to be made to the view given a base table row before and after an update.
void	clear()	Clears the current state so that the generator may be reused.
Collection<PartitionUpdate>	generateViewUpdates()	Returns the updates that needs to be done to the view given the base table updates passed to addBaseTableUpdate(org.apache.cassandra.db.rows.Row, org.apache.cassandra.db.rows.Row).

Methods inherited from class java.lang.Object

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

Constructor Details

ViewUpdateGenerator

public ViewUpdateGenerator(View view,
 DecoratedKey basePartitionKey,
 long nowInSec)

Creates a new ViewUpdateBuilder.

Parameters:

view - the view for which this will be building updates for.

basePartitionKey - the partition key for the base table partition for which we'll handle updates for.

nowInSec - the current time in seconds. Used to decide if data are live or not and as base reference for new deletions.

Method Details

addBaseTableUpdate

public void addBaseTableUpdate(Row existingBaseRow,
 Row mergedBaseRow)

Adds to this generator the updates to be made to the view given a base table row before and after an update.

Parameters:

existingBaseRow - the base table row as it is before an update.

mergedBaseRow - the base table row after the update is applied (note that this is not just the new update, but rather the resulting row).

generateViewUpdates

public Collection<PartitionUpdate> generateViewUpdates()

Returns the updates that needs to be done to the view given the base table updates passed to addBaseTableUpdate(org.apache.cassandra.db.rows.Row, org.apache.cassandra.db.rows.Row).

Returns:

the updates to do to the view.

clear

public void clear()

Clears the current state so that the generator may be reused.