com.bigdata.btree

Class IndexSegmentAddressManager

java.lang.Object

com.bigdata.rawstore.WormAddressManager

com.bigdata.btree.IndexSegmentAddressManager

All Implemented Interfaces:

IAddressManager

public class IndexSegmentAddressManager
extends WormAddressManager

Address manager supporting offsets that are encoded for one of several regions in an IndexSegmentStore. The regions are identified by a IndexSegmentRegion, which gets encoded into the offset component of the address. The offsets are relative to the start of the identified regions. The IndexSegmentCheckpoint record gives the start of each region.

Together with IndexSegmentRegion, this class class provides a workaround for node offsets (which are relative to the start of the nodes block) in contrast to leaf offsets (which are relative to a known offset from the start of the index segment file). This condition arises as a side effect of serializing nodes at the same time that the IndexSegmentBuilder is serializing leaves such that we can not group the nodes and leaves into distinct regions and know the absolute offset to each node or leaf as it is serialized.

The offsets for blobs are likewise relative to the start of a IndexSegmentRegion.BLOB region. The requirement for a blob region arises in a similar manner: blobs are serialized during the IndexSegmentBuilder operation onto a buffer and then bulk copied onto the output file. This means that only the relative offset into the blob region is available at the time that the blob's address is written in an index entry's value.

Version:

$Id$

Author:

Bryan Thompson

Field Summary

Fields

Modifier and Type	Field and Description
protected long	extentBlobs #of bytes in the blobs region.
protected long	extentLeaves #of bytes in the leaves region.
protected long	extentNodes #of bytes in the nodes region.
protected long	maxOffset The maximum offset (aka the #of bytes in the file).
protected long	offsetBlobs The offset within the file of the start of the blob region.
protected long	offsetLeaves The offset within the file of the start of the leaves region.
protected long	offsetNodes The offset within the file of the start of the node region.

Fields inherited from class com.bigdata.rawstore.WormAddressManager

_NULL_, MAX_OFFSET_BITS, MIN_OFFSET_BITS, SCALE_OUT_OFFSET_BITS, SCALE_UP_OFFSET_BITS

Fields inherited from interface com.bigdata.rawstore.IAddressManager

NULL

Constructor Summary

Constructors

Constructor and Description
IndexSegmentAddressManager(IndexSegmentCheckpoint checkpoint)

Method Summary

Methods

Modifier and Type	Method and Description
long	getOffset(long addr) Decodes the offset to extract the IndexSegmentRegion and then applies the appropriate offset for that region in order to convert the offset into an absolute offset into the store.
IndexSegmentRegion	getRegion(long addr) Return the region relative to which this address was encoded.
boolean	isLeafAddr(long addr) Return true IFF the starting address lies entirely within the region dedicated to the B+Tree leaves.
boolean	isNodeAddr(long addr) Return true IFF the starting address lies entirely within the region dedicated to the B+Tree nodes.
String	toString(long addr) Returns a representation of the address with the decoded offset and the region to which that offset is relative.

Methods inherited from class com.bigdata.rawstore.WormAddressManager

assertByteCount, assertOffset, assertOffsetBits, getByteCount, getMaxByteCount, getMaxByteCount, getMaxOffset, getOffsetBits, getPhysicalAddress, main, toAddr, toString

Methods inherited from class java.lang.Object

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

Field Detail

offsetLeaves

protected final long offsetLeaves

The offset within the file of the start of the leaves region. All leaves are written densely on the file beginning at this offset.

extentLeaves

protected final long extentLeaves

#of bytes in the leaves region.

offsetNodes

protected final long offsetNodes

The offset within the file of the start of the node region. All nodes are written densely on the file beginning at this offset. The child addresses for a node are relative to this offset and are automatically adjusted during decoding by this class.

extentNodes

protected final long extentNodes

#of bytes in the nodes region.

offsetBlobs

protected final long offsetBlobs

The offset within the file of the start of the blob region. All blob records are written densely on the file beginning at this offset. The blob addresses stored in a leaf are relative to this offset and are automatically adjusted during decoding by this class.

extentBlobs

protected final long extentBlobs

#of bytes in the blobs region.

maxOffset

protected final long maxOffset

The maximum offset (aka the #of bytes in the file).

Constructor Detail

IndexSegmentAddressManager

public IndexSegmentAddressManager(IndexSegmentCheckpoint checkpoint)

Parameters:

checkpoint -

Method Detail

getRegion

public final IndexSegmentRegion getRegion(long addr)

Return the region relative to which this address was encoded.

Note: ANY address MAY be encoded relative to the IndexSegmentRegion.BASE region. However, choosing IndexSegmentRegion.NODE or IndexSegmentRegion.BLOB regions does restrict the address to referencing a node (or blob) respectively.

Parameters:

addr - The address.

Returns:

The region relative to which this address was encoded.

getOffset

public final long getOffset(long addr)

Decodes the offset to extract the IndexSegmentRegion and then applies the appropriate offset for that region in order to convert the offset into an absolute offset into the store.

Specified by:

getOffset in interface IAddressManager

Overrides:

getOffset in class WormAddressManager

Parameters:

addr - The opaque identifier that is the within store locator for some datum.

Returns:

The offset of that datum.

toString

public String toString(long addr)

Returns a representation of the address with the decoded offset and the region to which that offset is relative.

Specified by:

toString in interface IAddressManager

Overrides:

toString in class WormAddressManager

Parameters:

addr - The opaque identifier that is the within store locator for some datum.

Returns:

A human readable representation.

isNodeAddr

public boolean isNodeAddr(long addr)

Return true IFF the starting address lies entirely within the region dedicated to the B+Tree nodes.

isLeafAddr

public boolean isLeafAddr(long addr)

Return true IFF the starting address lies entirely within the region dedicated to the B+Tree leaves.