net.openhft.chronicle.queue.impl.single.work.in.progress

Class SingleTailer

java.lang.Object

net.openhft.chronicle.queue.impl.single.work.in.progress.SingleTailer

All Implemented Interfaces:

ExcerptCommon, ExcerptTailer

public class SingleTailer
extends Object
implements ExcerptTailer

Created by peter.lawrey on 30/01/15.

Constructor Summary

Constructors

Constructor and Description
SingleTailer(AbstractChronicle chronicle, java.util.function.Function<net.openhft.chronicle.bytes.Bytes,net.openhft.chronicle.wire.Wire> wireProvider, net.openhft.chronicle.wire.WireType wireType)

Method Summary

Modifier and Type	Method and Description
long	cycle()
long	index()
boolean	index(long index) The indexes are stored in many excerpts, so the index2index tells chronicle where ( in other words the address of where ) the root first level index is stored.
boolean	index(long cycle, long index) Randomly select an Excerpt.
ChronicleQueue	queue()
boolean	readDocument(java.util.function.Consumer<net.openhft.chronicle.wire.WireIn> reader)
boolean	readDocument(net.openhft.chronicle.wire.ReadMarshallable reader)
ExcerptTailer	toEnd() Wind to the upper.
ExcerptTailer	toStart() Replay from the lower.

Methods inherited from class java.lang.Object

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

Constructor Detail

SingleTailer

public SingleTailer(@NotNull
                    AbstractChronicle chronicle,
                    @NotNull
                    java.util.function.Function<net.openhft.chronicle.bytes.Bytes,net.openhft.chronicle.wire.Wire> wireProvider,
                    net.openhft.chronicle.wire.WireType wireType)

Method Detail

readDocument

public boolean readDocument(java.util.function.Consumer<net.openhft.chronicle.wire.WireIn> reader)

readDocument

public boolean readDocument(@NotNull
                            net.openhft.chronicle.wire.ReadMarshallable reader)
                     throws IOException

Specified by:

readDocument in interface ExcerptTailer

Parameters:

reader - user to read the document

Returns:

true if successful

Throws:

IOException - if not able to read the chronicle file

index

public long index()

Specified by:

index in interface ExcerptTailer

Returns:

the index just read

cycle

public long cycle()

Specified by:

cycle in interface ExcerptTailer

Returns:

the cycle this tailer is on

index

public boolean index(long index)

The indexes are stored in many excerpts, so the index2index tells chronicle where ( in other words the address of where ) the root first level index is stored. The indexing works like a tree, but only 2 levels deep, the root of the tree is at index2index ( this first level index is 1MB in size and there is only one of them, it only holds the addresses of the second level indexes, there will be many second level indexes ( created on demand ), each is about 1MB in size (this second level index only stores the position of every 64th excerpt), so from every 64th excerpt a linear scan occurs. The indexes are only built when the indexer is run, this could be on a background thread. Each index is created into chronicle as an excerpt.

Specified by:

index in interface ExcerptTailer

Parameters:

index - index to look up

Returns:

true if this is a valid entries.

index

public boolean index(long cycle,
                     long index)
              throws IOException

Description copied from interface: ExcerptTailer

Randomly select an Excerpt.

Specified by:

index in interface ExcerptTailer

Parameters:

cycle - cycle

index - index to look up

Returns:

true if this is a valid entries.

Throws:

IOException - if not able to read the chronicle file

toStart

@NotNull
public ExcerptTailer toStart()

Description copied from interface: ExcerptTailer

Replay from the lower.

Specified by:

toStart in interface ExcerptTailer

Returns:

this Excerpt

toEnd

@NotNull
public ExcerptTailer toEnd()

Description copied from interface: ExcerptTailer

Wind to the upper.

Specified by:

toEnd in interface ExcerptTailer

Returns:

this Excerpt

queue

public ChronicleQueue queue()

Specified by:

queue in interface ExcerptCommon

Returns:

the queue associated with this Excerpt