ostore.util
Class VID

java.lang.Object
  |
  +--ostore.util.VID

All Implemented Interfaces:

Comparable, QuickSerializable

public class VID

extends Object

implements QuickSerializable, Comparable

A wrapper class for a DataObject version identifier. A VID contains a single SecureHash, which is either the VHash of a top-block, the VGUID of a top-block, or the GUID of a log object (LGUID). VID is also used to refer to the archival for of a DataObject, a disseminatable (DISS) (e.g. fragment or tombstone).

Version:

$Id: VID.java,v 1.17 2004/03/23 07:42:10 hweather Exp $

Author:

Dennis Geels

Field Summary

static byte	DISS The type code for a VID that consists of the DISS of the archival form of a DataObject block.
static byte	LGUID The type code for a VID that consists of the GUID of the log object for a version.
static String[]	STRING
static byte	VGUID The type code for a VID that consists of the VGUID of a DataObject's top block (A checkpoint GUID).
static byte	VHASH The type code for a VID that consists of the VHash of a DataObject's top block.

Constructor Summary

VID(byte type, SecureHash id)
Constructs a new VID.

VID(InputBuffer buffer)
Constructs a VID from its QuickSerializable form.

Method Summary

int	compareTo(Object o) Imposes an order on VIDs.
boolean	equals(Object other) Tests for equality (type and id).
SecureHash	get_id() Returns the VHash, VGUID, or GUID, as appropriate.
byte	get_type() Returns the type of identifier for this VID.
int	hashCode() Returns the hashcode of the internal identifier.
void	serialize(OutputBuffer buffer) Add the object to the buffer.
String	toString() Returns a human-readable representation of this VID.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

VHASH

public static final byte VHASH

The type code for a VID that consists of the VHash of a DataObject's top block.

See Also:

Constant Field Values

VGUID

public static final byte VGUID

The type code for a VID that consists of the VGUID of a DataObject's top block (A checkpoint GUID).

See Also:

Constant Field Values

LGUID

public static final byte LGUID

The type code for a VID that consists of the GUID of the log object for a version.

See Also:

Constant Field Values

DISS

public static final byte DISS

The type code for a VID that consists of the DISS of the archival form of a DataObject block.

See Also:

Constant Field Values

STRING

public static final String[] STRING

Constructor Detail

VID

public VID(byte type,
           SecureHash id)

Constructs a new VID.

VID

public VID(InputBuffer buffer)
    throws QSException

Constructs a VID from its QuickSerializable form.

Method Detail

get_type

public byte get_type()

Returns the type of identifier for this VID.

Returns:

One of VHASH, VGUID, LGUID, DISS

get_id

public SecureHash get_id()

Returns the VHash, VGUID, or GUID, as appropriate.

serialize

public void serialize(OutputBuffer buffer)

Description copied from interface: QuickSerializable

Add the object to the buffer.

Specified by:

serialize in interface QuickSerializable

Parameters:

buffer - the output buffer to add the object to

compareTo

public int compareTo(Object o)

Imposes an order on VIDs. The order is equivalent to the lexicographic order on corresponding VID.get_type(),VID.get_id() pairs.

Specified by:

compareTo in interface Comparable

hashCode

public int hashCode()

Returns the hashcode of the internal identifier.

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Tests for equality (type and id).

Overrides:

equals in class Object

Parameters:

other - possibly a VID.

Returns:

true iff other is a VID with the same identifier (including type).

toString

public String toString()

Returns a human-readable representation of this VID.

Overrides:

toString in class Object