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## com.trolltech.qt.core
Class QUuid

    java.lang.Object
      com.trolltech.qt.internal.QSignalEmitterInternal
          com.trolltech.qt.QSignalEmitter
              com.trolltech.qt.QtJambiObject
                  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.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`

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