org.jboss.messaging.util
Class UUID

java.lang.Object
  org.jboss.messaging.util.UUID

public class UUID
extends java.lang.Object

UUID represents Universally Unique Identifiers (aka Global UID in Windows world). UUIDs are usually generated via UUIDGenerator (or in case of 'Null UUID', 16 zero bytes, via static method getNullUUID()), or received from external systems. By default class caches the string presentations of UUIDs so that description is only created the first time it's needed. For memory stingy applications this caching can be turned off (note though that if uuid.toString() is never called, desc is never calculated so only loss is the space allocated for the desc pointer... which can of course be commented out to save memory). Similarly, hash code is calculated when it's needed for the first time, and from thereon that value is just returned. This means that using UUIDs as keys should be reasonably efficient. UUIDs can be compared for equality, serialized, cloned and even sorted. Equality is a simple bit-wise comparison. Ordering (for sorting) is done by first ordering based on type (in the order of numeric values of types), secondarily by time stamp (only for time-based time stamps), and finally by straight numeric byte-by-byte comparison (from most to least significant bytes).

Field Summary

static byte	INDEX_CLOCK_HI
static byte	INDEX_CLOCK_LO
static byte	INDEX_CLOCK_MID
static byte	INDEX_CLOCK_SEQUENCE
static byte	INDEX_TYPE
static byte	INDEX_VARIATION
static java.lang.String	NAMESPACE_DNS
static java.lang.String	NAMESPACE_OID
static java.lang.String	NAMESPACE_URL
static java.lang.String	NAMESPACE_X500
static byte	TYPE_DCE
static byte	TYPE_NAME_BASED
static byte	TYPE_NULL
static byte	TYPE_RANDOM_BASED
static byte	TYPE_TIME_BASED

Method Summary

boolean	equals(java.lang.Object o) Checking equality of UUIDs is easy; just compare the 128-bit number.
int	hashCode()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

INDEX_CLOCK_HI

public static final byte INDEX_CLOCK_HI

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Constant Field Values

INDEX_CLOCK_MID

public static final byte INDEX_CLOCK_MID

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Constant Field Values

INDEX_CLOCK_LO

public static final byte INDEX_CLOCK_LO

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Constant Field Values

INDEX_TYPE

public static final byte INDEX_TYPE

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Constant Field Values

INDEX_CLOCK_SEQUENCE

public static final byte INDEX_CLOCK_SEQUENCE

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Constant Field Values

INDEX_VARIATION

public static final byte INDEX_VARIATION

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Constant Field Values

TYPE_NULL

public static final byte TYPE_NULL

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Constant Field Values

TYPE_TIME_BASED

public static final byte TYPE_TIME_BASED

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Constant Field Values

TYPE_DCE

public static final byte TYPE_DCE

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Constant Field Values

TYPE_NAME_BASED

public static final byte TYPE_NAME_BASED

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Constant Field Values

TYPE_RANDOM_BASED

public static final byte TYPE_RANDOM_BASED

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Constant Field Values

NAMESPACE_DNS

public static final java.lang.String NAMESPACE_DNS

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Constant Field Values

NAMESPACE_URL

public static final java.lang.String NAMESPACE_URL

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Constant Field Values

NAMESPACE_OID

public static final java.lang.String NAMESPACE_OID

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Constant Field Values

NAMESPACE_X500

public static final java.lang.String NAMESPACE_X500

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Constant Field Values

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Checking equality of UUIDs is easy; just compare the 128-bit number.

Overrides:

equals in class java.lang.Object