Package org.apache.bookkeeper.mledger.impl

Class ManagedCursorContainer

java.lang.Object

org.apache.bookkeeper.mledger.impl.ManagedCursorContainer

All Implemented Interfaces:

java.lang.Iterable<ManagedCursor>

public class ManagedCursorContainer
extends java.lang.Object
implements java.lang.Iterable<ManagedCursor>

Contains all the cursors for a ManagedLedger.

The goal is to always know the slowest consumer and hence decide which is the oldest ledger we need to keep.

This data structure maintains a list and a map of cursors. The map is used to relate a cursor name with an entry in the linked-list. The list is a sorted double linked-list of cursors.

When a cursor is markDeleted, this list is updated and the cursor is moved in its new position.

To minimize the moving around, the order is maintained using the ledgerId, but not the entryId, since we only care about ledgers to be deleted.

Constructor Summary

Constructors

Constructor	Description
ManagedCursorContainer()

Method Summary

Modifier and Type	Method	Description
void	add(ManagedCursor cursor)
org.apache.commons.lang3.tuple.Pair<PositionImpl,PositionImpl>	cursorUpdated(ManagedCursor cursor, Position newPosition)	Signal that a cursor position has been updated and that the container must re-order the cursor list.
ManagedCursor	get(java.lang.String name)
ManagedCursor	getSlowestReader()
PositionImpl	getSlowestReaderPosition()	Get the slowest reader position, meaning older acknowledged position between all the cursors.
boolean	hasDurableCursors()	Check whether that are any durable cursors
boolean	isEmpty()	Check whether there are any cursors
java.util.Iterator<ManagedCursor>	iterator()
void	removeCursor(java.lang.String name)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ManagedCursorContainer

public ManagedCursorContainer()

Method Detail

add

public void add(ManagedCursor cursor)

get

public ManagedCursor get(java.lang.String name)

removeCursor

public void removeCursor(java.lang.String name)

cursorUpdated

public org.apache.commons.lang3.tuple.Pair<PositionImpl,PositionImpl> cursorUpdated(ManagedCursor cursor,
                                                                                          Position newPosition)

Signal that a cursor position has been updated and that the container must re-order the cursor list.

Parameters:

cursor -

Returns:

a pair of positions, representing the previous slowest consumer and the new slowest consumer (after the update).

getSlowestReaderPosition

public PositionImpl getSlowestReaderPosition()

Get the slowest reader position, meaning older acknowledged position between all the cursors.

Returns:

the slowest reader position

getSlowestReader

public ManagedCursor getSlowestReader()

isEmpty

public boolean isEmpty()

Check whether there are any cursors

Returns:

true is there are no cursors and false if there are

hasDurableCursors

public boolean hasDurableCursors()

Check whether that are any durable cursors

Returns:

true if there are durable cursors and false if there are not

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

iterator

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

Specified by:

iterator in interface java.lang.Iterable<ManagedCursor>