com.trolltech.qt.core
Class QUuid

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QUuid
All Implemented Interfaces:
QtJambiInterface, java.lang.Cloneable, java.lang.Comparable

public class QUuid
extends QtJambiObject
implements java.lang.Comparable, java.lang.Cloneable

The QUuid class stores a Universally Unique Identifier (UUID). Using Universally Unique IDentifiers (UUID) is a standard way to uniquely identify entities in a distributed computing environment. A UUID is a 16-byte (128-bit) number generated by some algorithm that is meant to guarantee that the UUID will be unique in the distributed computing environment where it is used. The acronym GUID is often used instead, Globally Unique IDentifiers, but it refers to the same thing. Actually, the GUID is one variant of UUID. Multiple variants are in use. Each UUID contains a bit field that specifies which type (variant) of UUID it is. Call variant() to discover which type of UUID an instance of QUuid contains. It extracts the three most signifcant bits of byte 8 of the 16 bytes. In QUuid, byte 8 is QUuid::data4[0]. If you create instances of QUuid using the constructor that accepts all the numeric values as parameters, use the following table to set the three most significant bits of parameter b1, which becomes QUuid::data4[0] and contains the variant field in its three most significant bits. In the table, 'x' means don't care.

msb0
msb1
msb2
Variant
0 x x NCS (Network Computing System)
1 0 x DCE (Distributed Computing Environment)
1 1 0 Microsoft (GUID)
1 1 1 Reserved for future expansion
If variant() returns QUuid::DCE , the UUID also contains a version field in the four most significant bits of QUuid::data3, and you can call version() to discover which version your QUuid contains. If you create instances of QUuid using the constructor that accepts all the numeric values as parameters, use the following table to set the four most significant bits of parameter w2, which becomes QUuid::data3 and contains the version field in its four most significant bits.
msb0
msb1
msb2
msb3
Version
0 0 0 1 Time
0 0 1 0 Embedded POSIX
0 0 1 1 Name
0 1 0 0 Random
The field layouts for the DCE versions listed in the table above are specified in the Network Working Group UUID Specification.

Most platforms provide a tool for generating new UUIDs, e.g. uuidgen and guidgen. You can also use createUuid(). UUIDs generated by createUuid() are of the random type. Their QUuid::Version bits are set to QUuid::Random , and their QUuid::Variant bits are set to QUuid::DCE . The rest of the UUID is composed of random numbers. Theoretically, this means there is a small chance that a UUID generated by createUuid() will not be unique. But it is a very small chance.

UUIDs can be constructed from numeric values or from strings, or using the static createUuid() function. They can be converted to a string with toString(). UUIDs have a variant() and a version(), and null UUIDs return true from isNull().


Nested Class Summary
static class QUuid.Variant
          This enum defines the values used in the variant field of the UUID.
static class QUuid.Version
          This enum defines the values used in the version field of the UUID.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QUuid()
          Creates the null UUID.
QUuid(int l, char w1, char w2, byte b1, byte b2, byte b3, byte b4, byte b5, byte b6, byte b7, byte b8)
          Creates a UUID with the value specified by the parameters, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8.
QUuid(java.lang.String arg__1)
          Creates a QUuid object from the string text, which must be formatted as five hex fields separated by '-', e.
 
Method Summary
 QUuid clone()
          This method is reimplemented for internal reasons
static QUuid createUuid()
          On any platform other than Windows, this function returns a new UUID with variant QUuid::DCE and version QUuid::Random .
 int data1()
          Returns the data of this QUuid.
 char data2()
          Returns the data of this QUuid.
 char data3()
          Returns the data of this QUuid.
 byte[] data4()
           
 boolean isNull()
          Returns true if this is the null UUID {00000000-0000-0000-0000-000000000000}; otherwise returns false.
 void readFrom(QDataStream arg__1)
          Reads a QUuid
 void setData1(int data1)
          Sets the data of this QUuid to data1.
 void setData2(char data2)
          Sets the data of this QUuid to data2.
 void setData3(char data3)
          Sets the data of this QUuid to data3.
 void setData4(byte[] data4)
           
 java.lang.String toString()
          Returns a string representation of the this QUuid.
 QUuid.Variant variant()
          Returns the value in the variant field of the UUID.
 QUuid.Version version()
          Returns the version field of the UUID, if the UUID's variant field is QUuid::DCE .
 void writeTo(QDataStream arg__1)
          Writes thisQUuid
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.lang.Comparable
compareTo
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QUuid

public QUuid()
Creates the null UUID. toString() will output the null UUID as "{00000000-0000-0000-0000-000000000000}".


QUuid

public QUuid(java.lang.String arg__1)
Creates a QUuid object from the string text, which must be formatted as five hex fields separated by '-', e. ., "{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}" where 'x' is a hex digit. The curly braces shown here are optional, but it is normal to include them. If the conversion fails, a null UUID is created. See toString() for an explanation of how the five hex fields map to the public data members in QUuid.

See also:
toString(), and QUuid().


QUuid

public QUuid(int l,
             char w1,
             char w2,
             byte b1,
             byte b2,
             byte b3,
             byte b4,
             byte b5,
             byte b6,
             byte b7,
             byte b8)
Creates a UUID with the value specified by the parameters, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8.

Example:

Missing snippet: doc/src/snippets/code/src_corelib_plugin.quuid.cpp.

Method Detail

isNull

public final boolean isNull()
Returns true if this is the null UUID {00000000-0000-0000-0000-000000000000}; otherwise returns false.


writeTo

public final void writeTo(QDataStream arg__1)
Writes thisQUuid


readFrom

public final void readFrom(QDataStream arg__1)
Reads a QUuid


toString

public final java.lang.String toString()
Returns a string representation of the this QUuid.

Overrides:
toString in class java.lang.Object

variant

public final QUuid.Variant variant()
Returns the value in the variant field of the UUID. If the return value is QUuid::DCE , call version() to see which layout it uses. The null UUID is considered to be of an unknown variant.

See also:
version().


version

public final QUuid.Version version()
Returns the version field of the UUID, if the UUID's variant field is QUuid::DCE . Otherwise it returns QUuid::VerUnknown .

See also:
variant().


createUuid

public static QUuid createUuid()
On any platform other than Windows, this function returns a new UUID with variant QUuid::DCE and version QUuid::Random . The random numbers used to construct the UUID are obtained from the local pseudo-random generator, which is usually not a cryptographic quality random number generator. Therefore, a UUID generated by this function can't be guaranteed to be unique.

On a Windows platform, a GUID is generated, which almost certainly will be unique, on this or any other system, networked or not.

See also:
variant(), and version().


setData1

public final void setData1(int data1)
Sets the data of this QUuid to data1.


data1

public final int data1()
Returns the data of this QUuid.


setData2

public final void setData2(char data2)
Sets the data of this QUuid to data2.


data2

public final char data2()
Returns the data of this QUuid.


setData3

public final void setData3(char data3)
Sets the data of this QUuid to data3.


data3

public final char data3()
Returns the data of this QUuid.


setData4

public final void setData4(byte[] data4)

data4

public final byte[] data4()

clone

public QUuid clone()
This method is reimplemented for internal reasons

Overrides:
clone in class java.lang.Object