Package org.apache.jackrabbit.oak.segment.spi.persistence.persistentcache

Class CachingSegmentArchiveReader

java.lang.Object

org.apache.jackrabbit.oak.segment.spi.persistence.persistentcache.CachingSegmentArchiveReader

All Implemented Interfaces:

Closeable, AutoCloseable, SegmentArchiveReader

public class CachingSegmentArchiveReader
extends Object
implements SegmentArchiveReader

Constructor Summary

Constructors

Constructor	Description
CachingSegmentArchiveReader(@NotNull PersistentCache persistentCache, @NotNull SegmentArchiveReader delegate)

Method Summary

Modifier and Type	Method	Description
void	close()	Close the archive.
boolean	containsSegment(long msb, long lsb)	Check if the segment exists.
@NotNull Buffer	getBinaryReferences()	Load binary references.
int	getEntrySize(int size)	Transforms the segment size in bytes into the effective size on disk for the given entry (eg.
@Nullable Buffer	getGraph()	Load the segment graph.
@NotNull String	getName()	Get the name of the archive.
boolean	hasGraph()	Check if the segment graph has been persisted for this archive.
boolean	isRemote()	This method returns true if the storage is accessed via a network protocol, not tight to the traditional storage technology, for example, HTTP.
long	length()	Get the current length of the archive.
List<SegmentArchiveEntry>	listSegments()	List all the segments, in the order as they have been written to the archive.
@Nullable Buffer	readSegment(long msb, long lsb)	Read the segment.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingSegmentArchiveReader

public CachingSegmentArchiveReader(@NotNull
                                   @NotNull PersistentCache persistentCache,
                                   @NotNull
                                   @NotNull SegmentArchiveReader delegate)

Method Detail

readSegment

@Nullable
public @Nullable Buffer readSegment(long msb,
                                    long lsb)
                             throws IOException

Description copied from interface: SegmentArchiveReader

Read the segment.

Specified by:

readSegment in interface SegmentArchiveReader

Parameters:

msb - the most significant bits of the identifier of the segment

lsb - the least significant bits of the identifier of the segment

Returns:

byte buffer containing the segment data or null if the segment doesn't exist

Throws:

IOException

containsSegment

public boolean containsSegment(long msb,
                               long lsb)

Description copied from interface: SegmentArchiveReader

Check if the segment exists.

Specified by:

containsSegment in interface SegmentArchiveReader

Parameters:

msb - the most significant bits of the identifier of the segment

lsb - the least significant bits of the identifier of the segment

Returns:

true if the segment exists

listSegments

public List<SegmentArchiveEntry> listSegments()

Description copied from interface: SegmentArchiveReader

List all the segments, in the order as they have been written to the archive.

Specified by:

listSegments in interface SegmentArchiveReader

Returns:

segment list, ordered by their position in the archive

getGraph

@Nullable
public @Nullable Buffer getGraph()
                          throws IOException

Description copied from interface: SegmentArchiveReader

Load the segment graph.

Specified by:

getGraph in interface SegmentArchiveReader

Returns:

byte buffer representing the graph or null if the graph hasn't been persisted.

Throws:

IOException

hasGraph

public boolean hasGraph()

Description copied from interface: SegmentArchiveReader

Check if the segment graph has been persisted for this archive.

Specified by:

hasGraph in interface SegmentArchiveReader

Returns:

true if the graph exists, false otherwise

getBinaryReferences

@NotNull
public @NotNull Buffer getBinaryReferences()
                                    throws IOException

Description copied from interface: SegmentArchiveReader

Load binary references.

Specified by:

getBinaryReferences in interface SegmentArchiveReader

Returns:

byte buffer representing the binary references structure.

Throws:

IOException

length

public long length()

Description copied from interface: SegmentArchiveReader

Get the current length of the archive.

Specified by:

length in interface SegmentArchiveReader

Returns:

length of the archive, in bytes

getName

@NotNull
public @NotNull String getName()

Description copied from interface: SegmentArchiveReader

Get the name of the archive.

Specified by:

getName in interface SegmentArchiveReader

Returns:

archive name

close

public void close()
           throws IOException

Description copied from interface: SegmentArchiveReader

Close the archive.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface SegmentArchiveReader

Throws:

IOException

getEntrySize

public int getEntrySize(int size)

Description copied from interface: SegmentArchiveReader

Transforms the segment size in bytes into the effective size on disk for the given entry (eg. by adding the number of padding bytes, header, etc.)

Specified by:

getEntrySize in interface SegmentArchiveReader

Parameters:

size - the segment size in bytes

Returns:

the number of bytes effectively used on the storage to save the segment

isRemote

public boolean isRemote()

Description copied from interface: SegmentArchiveReader

This method returns true if the storage is accessed via a network protocol, not tight to the traditional storage technology, for example, HTTP. Based on that info, for instance, calling classes can decide to update archive metadata (graph, binary references, index) more frequently, and not only when the archive is being closed. With that multiple Oak processes can access the storage simultaneously, with one process in read-write mode and one or more processes in read-only mode.

Specified by:

isRemote in interface SegmentArchiveReader

Returns: