ostore.archive
Class FragmentBucket

java.lang.Object
  |
  +--ostore.archive.FragmentBucket

All Implemented Interfaces:

Cacheable, DisseminatableBucket, QuickSerializable

public class FragmentBucket

extends Object

implements DisseminatableBucket

FragmentBucket is a class to store all or a subset of the fragments for a single OceanStore block.

Version:

$Id: FragmentBucket.java,v 1.29 2004/03/23 02:30:20 hweather Exp $

Author:

Hakim Weatherspoon

Field Summary

protected boolean[]	_ackFrags Array to store whether a fragment has been acknowledged after dissemination.
protected boolean	_archiveInterpretFlag Flag determines whether the archive should do "something" special with the decoded block i.e create data obj.
protected long	_blockType blockType is the type of block we are encoding or decoding.
protected boolean	_canDecode boolean on whether can decode.
protected long	_endTime startTime and endTime are timers for dissemination and recoalescing of a disseminatable bucket.
protected Fragment[]	_frags Array to store the fragments (its length is based on whether we are waiting to disseminate, or are recoalescing, the fragments)
protected int	_frags_free_space Current free space pointer into _frags
protected int	_nackCount Number of NACK's received.
protected SecureHash	_nextBucket Points to the next FragmentBucket in a chain of FragmentBuckets.
protected NodeId	_node_id _node_id is the NodeId of the local server where this class is running.
protected int	_numAcksRecv Number of ack's recv'd for disseminated fragments belonging to a particular fragmentBucket.
protected SecureHash	_refGuid reference to guid of top most root block (GUID which refers to this FB).
protected long	_startTime startTime and endTime are timers for dissemination and recoalescing of a disseminatable bucket.
protected boolean	_successfullyDecoded boolean on whether can decode.
static boolean	COMPARE_MESSAGES This determines if messages are compared after having been decoded in Reconstructor...for debuggin purposes only.
int[]	enc_msg
int[]	old_msg

Constructor Summary

FragmentBucket(InputBuffer buffer)
Constructs a FragmentBucket from its serialized form.

FragmentBucket(int numFrags, NodeId node_id, SecureHash node_guid)
Constructor: initializes FragmentBucket to contain a number of fragments.

FragmentBucket(NodeId node_id, SecureHash node_guid)
Default constructor

Method Summary

void	add(Disseminatable diss) Add a disseminatable object to this bucket.
boolean	canDecode() Determine if we can decode this bucket's object.
void	clear() clears internal data structures.
static int	computeMemoryRequirement(int bSize, int numFrags, int inverseRate, int type) computMemoryRequirement computes the memory requirement for a single disseminatable.
boolean	getAcksRecv(int index) getAcksRecv return true if fragment at given index has been received; otherwise, false.
boolean	getArchiveInterpretFlag() returns archive interpret decoded block flag.
long	getBlockType() getBlockType returns the type of block that we are encoding or decoding.
Disseminatable	getDisseminatable(int index) Retrieve a single Disseminatable object
long	getEndTime() getEndTime returns the time the Bucket was destroyed(removed from table).
Fragment	getFragment(int index) Retrieve a single Disseminatable object
SecureHash	getGuid() Get GUID that is the name of the diss objects in this bucket.
int	getLength() Retrieve the total capacity of this bucket.
int	getNackCount() getNackCount returns the number of NACK's received.
SecureHash	getNextBucket() Get the next Bucket in this chain.
int	getNumAcksRecv() getNumAcksRecv returns the number of ack's recv'd
int	getNumBytes() Retrieve the total number of bytes stored in this bucket.
int	getNumGood() Retrieve the total number of disseminatables stored in this bucket.
SecureHash	getRefGuid() Get GUID that refers to this bucket (in some higher-level hashtable).
long	getStartTime() getStartTime returns the time the Bucket was created(put on table).
void	incrNackCount() incrNackCount increments the NACK count.
protected static boolean	instanceRandomContains(NodeId node_id) instanceRandomContains returns true if map of instance instance variables contains node_id, false otherwise.
protected static void	instanciateRandom(int seed, NodeId node_id) instanciateRandom creates an instance of a Random associated with NodeId and instanciated with the seed.
void	loseFragments(double fractionToKeep) This routine is used for debuggin;
static int	OVERHEAD(int numFrags) overhead of a fragment bucket (in bytes).
boolean	receivedAllAcks(double percentRequired) ReceivedAllAcks returns true if all disseminated fragments have been ack'd otherwise returns false.
boolean	recv(Disseminatable diss) Receive a disseminatable object (presumably from the network) and add it to this bucket.
void	reset(NodeId node_id, SecureHash node_guid) resets internal data structures.
void	serialize(OutputBuffer buffer) Specified by ostore.util.QuickSerializable
void	setAckRecv(int index) Receive an acknowledgement
void	setArchiveInterpretFlag(boolean flag) set's archive interpret decode block flag.
void	setBlockType(long type) setBlockType sets the type of block that we are encoding or decoding.
void	setDecoded(boolean success) Set successfullyDecoded ...
void	setEndTime(long time) setEndTime sets the time the Bucket was destroyed(removed from table).
void	setNextBucket(SecureHash bucket) Set the next Bucket in this chain.
void	setRefGuid(SecureHash guid) Set GUID that refers to this bucket (in some higher-level hashtable).
void	setStartTime(long time) setStartTime sets the time the Bucket was created(put on table).
boolean	testAndSetDecoded() Atomically test successfullyDecoded.
String	toString() Specified by java.lang.Object

Methods inherited from class java.lang.Object

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

Field Detail

COMPARE_MESSAGES

public static boolean COMPARE_MESSAGES

This determines if messages are compared after having been decoded in Reconstructor...for debuggin purposes only.

old_msg

public int[] old_msg

enc_msg

public int[] enc_msg

_startTime

protected long _startTime

startTime and endTime are timers for dissemination and recoalescing of a disseminatable bucket.

_endTime

protected long _endTime

startTime and endTime are timers for dissemination and recoalescing of a disseminatable bucket.

_blockType

protected long _blockType

blockType is the type of block we are encoding or decoding.

_frags

protected Fragment[] _frags

Array to store the fragments (its length is based on whether we are waiting to disseminate, or are recoalescing, the fragments)

_ackFrags

protected boolean[] _ackFrags

Array to store whether a fragment has been acknowledged after dissemination.

_numAcksRecv

protected int _numAcksRecv

Number of ack's recv'd for disseminated fragments belonging to a particular fragmentBucket.

_nackCount

protected int _nackCount

Number of NACK's received.

_frags_free_space

protected int _frags_free_space

Current free space pointer into _frags

_nextBucket

protected SecureHash _nextBucket

Points to the next FragmentBucket in a chain of FragmentBuckets. This is used to group FragmentBuckets of the same version / checkpt

_refGuid

protected SecureHash _refGuid

reference to guid of top most root block (GUID which refers to this FB).

_canDecode

protected boolean _canDecode

boolean on whether can decode.

_successfullyDecoded

protected boolean _successfullyDecoded

boolean on whether can decode.

_archiveInterpretFlag

protected boolean _archiveInterpretFlag

Flag determines whether the archive should do "something" special with the decoded block i.e create data obj.

_node_id

protected NodeId _node_id

_node_id is the NodeId of the local server where this class is running.

Constructor Detail

FragmentBucket

public FragmentBucket(NodeId node_id,
                      SecureHash node_guid)

Default constructor

FragmentBucket

public FragmentBucket(int numFrags,
                      NodeId node_id,
                      SecureHash node_guid)

Constructor: initializes FragmentBucket to contain a number of fragments.

FragmentBucket

public FragmentBucket(InputBuffer buffer)
               throws QSException

Constructs a FragmentBucket from its serialized form.

Parameters:

buffer - serialized form of object.

Method Detail

OVERHEAD

public static int OVERHEAD(int numFrags)

overhead of a fragment bucket (in bytes).

computeMemoryRequirement

public static int computeMemoryRequirement(int bSize,
                                           int numFrags,
                                           int inverseRate,
                                           int type)

computMemoryRequirement computes the memory requirement for a single disseminatable.

Parameters:

bSize - = size of block in bytes.

numFrags - = total number of fragments for block.

inverseRate - = inverseRate of encoding.

type - = type of erasure coding.

Returns:

return = the fragment size corresponding to the input parameters.

instanciateRandom

protected static void instanciateRandom(int seed,
                                        NodeId node_id)

instanciateRandom creates an instance of a Random associated with NodeId and instanciated with the seed.

Parameters:

seed - = seed to instanciate Random variable with.

node_id - = NodeId to associate with Random variable.

instanceRandomContains

protected static boolean instanceRandomContains(NodeId node_id)

instanceRandomContains returns true if map of instance instance variables contains node_id, false otherwise.

Parameters:

node_id - = NodeId to test.

Returns:

true if map of instance instance variables contains node_id, false otherwise.

clear

public void clear()

clears internal data structures.

Specified by:

clear in interface DisseminatableBucket

reset

public void reset(NodeId node_id,
                  SecureHash node_guid)

resets internal data structures.

Specified by:

reset in interface DisseminatableBucket

serialize

public void serialize(OutputBuffer buffer)

Specified by ostore.util.QuickSerializable

Specified by:

serialize in interface QuickSerializable

Parameters:

buffer - the output buffer to add the object to

getBlockType

public long getBlockType()

getBlockType returns the type of block that we are encoding or decoding.

Returns:

= type of block that we are encoding or decoding.

getStartTime

public long getStartTime()

getStartTime returns the time the Bucket was created(put on table).

Specified by:

getStartTime in interface DisseminatableBucket

Returns:

= time bucket was created (put on hash table).

getEndTime

public long getEndTime()

getEndTime returns the time the Bucket was destroyed(removed from table).

Specified by:

getEndTime in interface DisseminatableBucket

Returns:

= time bucket bucket was destroyed (removed from hash table).

getArchiveInterpretFlag

public boolean getArchiveInterpretFlag()

returns archive interpret decoded block flag.

Returns:

== archive interpret decoded flag.

setBlockType

public void setBlockType(long type)

setBlockType sets the type of block that we are encoding or decoding.

Parameters:

type - = type of block that we are encoding or decoding.

setStartTime

public void setStartTime(long time)

setStartTime sets the time the Bucket was created(put on table).

Specified by:

setStartTime in interface DisseminatableBucket

Parameters:

time - = the time the Bucket was created.

setEndTime

public void setEndTime(long time)

setEndTime sets the time the Bucket was destroyed(removed from table).

Specified by:

setEndTime in interface DisseminatableBucket

Parameters:

time - == the time the Bucket was destroyed.

setArchiveInterpretFlag

public void setArchiveInterpretFlag(boolean flag)

set's archive interpret decode block flag.

Parameters:

flag - == archive interpret decode block flag.

getNumBytes

public int getNumBytes()

Retrieve the total number of bytes stored in this bucket.

Specified by:

getNumBytes in interface DisseminatableBucket

Returns:

== the total number of bytes stored in this bucket.

getNextBucket

public SecureHash getNextBucket()

Get the next Bucket in this chain.

Specified by:

getNextBucket in interface DisseminatableBucket

Returns:

== the next bucket in this chain.

setNextBucket

public void setNextBucket(SecureHash bucket)

Set the next Bucket in this chain.

Specified by:

setNextBucket in interface DisseminatableBucket

Parameters:

bucket - == the next bucket in this chain.

getRefGuid

public SecureHash getRefGuid()

Get GUID that refers to this bucket (in some higher-level hashtable).

Specified by:

getRefGuid in interface DisseminatableBucket

Returns:

== the guid that refers to this bucket.

setRefGuid

public void setRefGuid(SecureHash guid)

Set GUID that refers to this bucket (in some higher-level hashtable).

Specified by:

setRefGuid in interface DisseminatableBucket

Parameters:

guid - == guid that refers to this bucket.

getGuid

public SecureHash getGuid()

Get GUID that is the name of the diss objects in this bucket.

Specified by:

getGuid in interface DisseminatableBucket

Returns:

== guid that is the name of the diss objects in this bucket.

getNumGood

public int getNumGood()

Retrieve the total number of disseminatables stored in this bucket.

Specified by:

getNumGood in interface DisseminatableBucket

Returns:

== total number of disseminatables stored in this bucket.

getLength

public int getLength()

Retrieve the total capacity of this bucket.

Specified by:

getLength in interface DisseminatableBucket

Returns:

== the total capacity of this bucket.

getDisseminatable

public Disseminatable getDisseminatable(int index)

Retrieve a single Disseminatable object

Specified by:

getDisseminatable in interface DisseminatableBucket

Parameters:

index - == index of the disseminatable object to retrieve.

Returns:

== disseminatable object that corresponds to index.

getFragment

public Fragment getFragment(int index)

Retrieve a single Disseminatable object

Parameters:

index - == index of the disseminatable object to retrieve.

Returns:

== disseminatable object that corresponds to index.

getNackCount

public int getNackCount()

getNackCount returns the number of NACK's received.

Specified by:

getNackCount in interface DisseminatableBucket

Returns:

return==number of NACK's received.

incrNackCount

public void incrNackCount()

incrNackCount increments the NACK count.

Specified by:

incrNackCount in interface DisseminatableBucket

add

public void add(Disseminatable diss)

Add a disseminatable object to this bucket.

Specified by:

add in interface DisseminatableBucket

Parameters:

diss - == the object to add.

setAckRecv

public void setAckRecv(int index)

Receive an acknowledgement

Specified by:

setAckRecv in interface DisseminatableBucket

Parameters:

index - == index of the Disseminatable to mark as ack'ed.

getAcksRecv

public boolean getAcksRecv(int index)

getAcksRecv return true if fragment at given index has been received; otherwise, false.

Specified by:

getAcksRecv in interface DisseminatableBucket

Parameters:

index - Index of disseminatable to test if ack has been received.

Returns:

true if fragment at given index has been received; otherwise, false.

getNumAcksRecv

public int getNumAcksRecv()

getNumAcksRecv returns the number of ack's recv'd

Specified by:

getNumAcksRecv in interface DisseminatableBucket

Returns:

number of ack's recv'd

receivedAllAcks

public boolean receivedAllAcks(double percentRequired)

ReceivedAllAcks returns true if all disseminated fragments have been ack'd otherwise returns false.

Specified by:

receivedAllAcks in interface DisseminatableBucket

Parameters:

percentRequired - == perecent of acks we will actually count as being "all" of the acks.

Returns:

return==true if all disseminated fragments have been ack'd otherwise returns false.

recv

public boolean recv(Disseminatable diss)

Receive a disseminatable object (presumably from the network) and add it to this bucket. This routine is called whenever we receive a new fragment during recoalescence. NOTE: The fragment should be verified before calling this function

Specified by:

recv in interface DisseminatableBucket

Parameters:

diss - the object to add.

Returns:

true iff we have enough diss objects to safely decode.

canDecode

public boolean canDecode()

Determine if we can decode this bucket's object.

Specified by:

canDecode in interface DisseminatableBucket

Returns:

== true iff we can decode this bucket's object.

testAndSetDecoded

public boolean testAndSetDecoded()

Atomically test successfullyDecoded. If it is false, set it to true ALERT: Make this synchronized!.

Specified by:

testAndSetDecoded in interface DisseminatableBucket

Returns:

== return true/false whether object is being decoded.

setDecoded

public void setDecoded(boolean success)

Set successfullyDecoded ... ALERT: Make this synchronized!

Specified by:

setDecoded in interface DisseminatableBucket

Parameters:

success - == set decoded to true or false

loseFragments

public void loseFragments(double fractionToKeep)

This routine is used for debuggin;

Parameters:

fractionToKeep - == fraction of fragments to keep.

toString

public String toString()

Specified by java.lang.Object

Overrides:

toString in class Object