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

Interface SegmentArchiveReader

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

SegmentTarReader

public interface SegmentArchiveReader
extends Closeable

This interface represents a read-only segment archive. Since the underlying data structure is immutable, the implementation should be thread safe.

Method Summary

Modifier and Type	Method and Description
void	close() Close the archive.
boolean	containsSegment(long msb, long lsb) Check if the segment exists.
@NotNull org.apache.jackrabbit.oak.commons.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. by adding the number of padding bytes, header, etc.)
@Nullable org.apache.jackrabbit.oak.commons.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.
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 org.apache.jackrabbit.oak.commons.Buffer	readSegment(long msb, long lsb) Read the segment.

Method Detail

readSegment

@Nullable
@Nullable org.apache.jackrabbit.oak.commons.Buffer readSegment(long msb,
                                                                          long lsb)
                                                                   throws IOException

Read the segment.

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

boolean containsSegment(long msb,
                        long lsb)

Check if the segment exists.

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

List<SegmentArchiveEntry> listSegments()

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

Returns:

segment list, ordered by their position in the archive

getGraph

@Nullable
@Nullable org.apache.jackrabbit.oak.commons.Buffer getGraph()
                                                                throws IOException

Load the segment graph.

Returns:

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

Throws:

IOException

hasGraph

boolean hasGraph()

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

Returns:

true if the graph exists, false otherwise

getBinaryReferences

@NotNull
@NotNull org.apache.jackrabbit.oak.commons.Buffer getBinaryReferences()
                                                                         throws IOException

Load binary references.

Returns:

byte buffer representing the binary references structure.

Throws:

IOException

length

long length()

Get the current length of the archive.

Returns:

length of the archive, in bytes

getName

@NotNull
@NotNull String getName()

Get the name of the archive.

Returns:

archive name

close

void close()
    throws IOException

Close the archive.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

getEntrySize

int getEntrySize(int size)

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.)

Parameters:

size - the segment size in bytes

Returns:

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