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## com.trolltech.qt.core
Class QBuffer

    java.lang.Object
      com.trolltech.qt.QSignalEmitter
          com.trolltech.qt.QtJambiObject
              com.trolltech.qt.core.QObject
                  com.trolltech.qt.core.QIODevice
                      com.trolltech.qt.core.QBuffer

All Implemented Interfaces:
  QtJambiInterface

    public class QBuffer

extends QIODevice

The `QBuffer` class provides a `QIODevice` interface for a `QByteArray`. `QBuffer` allows you to access a `QByteArray` using the `QIODevice` interface. The `QByteArray` is treated just as a standard random-accessed file. Example:

        QBuffer buffer = new QBuffer();
        int b;

        buffer.open(QIODevice.OpenModeFlag.ReadWrite);
        buffer.write(new QByteArray("Qt rocks!"));
        buffer.seek(0);
        b = buffer.getByte();  // b == 'Q'
        b = buffer.getByte();  // b == 't'
        b = buffer.getByte();  // b == ' '
        b = buffer.getByte();  // b == 'r'

By default, an internal `QByteArray` buffer is created for you when you create a `QBuffer`. You can access this buffer directly by calling `buffer()`. You can also use `QBuffer` with an existing `QByteArray` by calling `setBuffer()`, or by passing your array to `QBuffer`'s constructor.

Call `open()` to open the buffer. Then call `write()` or putChar() to write to the buffer, and `read()`, `readLine()`, `readAll()`, or getChar() to read from it. `size()` returns the current size of the buffer, and you can seek to arbitrary positions in the buffer by calling `seek()`. When you are done with accessing the buffer, call `close()`.

The following code snippet shows how to write data to a `QByteArray` using `QDataStream` and `QBuffer`:

        QByteArray byteArray = new QByteArray();
        QBuffer buffer = new QBuffer(byteArray);
        buffer.open(QIODevice.OpenModeFlag.WriteOnly);

        QDataStream out = new QDataStream(buffer);
        out.writeString("Any string will do.");

Effectively, we convert the application's `QPalette` into a byte array. Here's how to read the data from the `QByteArray`:

        String string = "";
        QBuffer buffer = new QBuffer(byteArray);
        buffer.open(QIODevice.OpenModeFlag.ReadOnly);

        QDataStream in = new QDataStream(buffer);
        string = in.readString();

`QTextStream` and `QDataStream` also provide convenience constructors that take a `QByteArray` and that create a `QBuffer` behind the scenes.

`QBuffer` emits `readyRead()` when new data has arrived in the buffer. By connecting to this signal, you can use `QBuffer` to store temporary data before processing it. For example, you can pass the buffer to `QFtp` when downloading a file from an FTP server. Whenever a new payload of data has been downloaded, `readyRead()` is emitted, and you can process the data that just arrived. `QBuffer` also emits `bytesWritten()` every time new data has been written to the buffer.

See also:
  `QFile`, `QDataStream`, `QTextStream`, and `QByteArray`.

Nested Class Summary

Nested classes/interfaces inherited from class com.trolltech.qt.core.QIODevice
`QIODevice.OpenMode, QIODevice.OpenModeFlag`

Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
`QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9`

Field Summary

Fields inherited from class com.trolltech.qt.core.QIODevice
`aboutToClose, bytesWritten, readChannelFinished, readyRead`

Constructor Summary
`QBuffer()` Constructs an empty buffer with the given `parent`.
`QBuffer(QByteArray byteArray)` Constructs a new QByteArray of which contents will be equal to `byteArray`.
`QBuffer(QByteArray byteArray, QObject parent)` Constructs a QBuffer that uses the QByteArray pointed to by `byteArray` as its internal buffer, and with the given `parent`.
`QBuffer(QObject parent)` Constructs an empty buffer with the given `parent`.

Method Summary
`QByteArray` | `buffer()` Returns a reference to the `QBuffer`'s internal buffer.
`QByteArray` | `data()` Returns the data contained in the buffer.
`static QBuffer` | `fromNativePointer(QNativePointer nativePointer)` This method returns the QBuffer instance pointed to by `nativePointer`.
`void` | `setBuffer(QByteArray byteArray)` Makes the QBuffer use the `byteArray` as its internal buffer.
`void` | `setData(byte[] data)` Sets the contents of this QBuffer to `data`
`void` | `setData(QByteArray data)` Sets the contents of the internal buffer to be `data`.

Methods inherited from class com.trolltech.qt.core.QIODevice
`atEnd, bytesAvailable, bytesToWrite, canReadLine, close, errorString, getByte, isOpen, isReadable, isSequential, isTextModeEnabled, isWritable, open, open, openMode, peek, peek, pos, putByte, read, read, readAll, readData, readLine, readLine, readLine, readLineData, reset, seek, setErrorString, setOpenMode, setOpenMode, setTextModeEnabled, size, ungetByte, waitForBytesWritten, waitForReadyRead, write, write, writeData`

Methods inherited from class com.trolltech.qt.core.QObject
`childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty`

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 java.lang.Object
`clone, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Methods inherited from interface com.trolltech.qt.QtJambiInterface
`disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership`

Constructor Detail

### QBuffer

    public QBuffer()

  Constructs an empty buffer with the given `parent`. You can call `setData()` to fill the buffer with data, or you can open it in write mode and use `write()`.

See also:
  `open()`.

### QBuffer

    public QBuffer(QObject parent)

  Constructs an empty buffer with the given `parent`. You can call `setData()` to fill the buffer with data, or you can open it in write mode and use `write()`.

See also:
  `open()`.

### QBuffer

    public QBuffer(QByteArray byteArray,
                   QObject parent)

  Constructs a QBuffer that uses the QByteArray pointed to by `byteArray` as its internal buffer, and with the given `parent`. The caller is responsible for ensuring that `byteArray` remains valid until the QBuffer is destroyed, or until setBuffer() is called to change the buffer. QBuffer doesn't take ownership of the QByteArray.

  If you open the buffer in write-only mode or read-write mode and write something into the QBuffer, `byteArray` will be modified.

### QBuffer

    public QBuffer(QByteArray byteArray)

  Constructs a new QByteArray of which contents will be equal to `byteArray`.

Method Detail

### buffer

    public final QByteArray buffer()

  Returns a reference to the `QBuffer`'s internal buffer. You can use it to modify the `QByteArray` behind the `QBuffer`'s back.

See also:
  `setBuffer()`, and `data()`.

### data

    public final QByteArray data()

  Returns the data contained in the buffer.

  This is the same as `buffer()`.

See also:
  `setData()`, and `setBuffer()`.

### setData

    public final void setData(QByteArray data)

  Sets the contents of the internal buffer to be `data`. This is the same as assigning `data` to `buffer()`.

  Does nothing if `isOpen()` is true.

See also:
  `data()`, and `setBuffer()`.

### fromNativePointer

    public static QBuffer fromNativePointer(QNativePointer nativePointer)

  This method returns the QBuffer instance pointed to by `nativePointer`.

### setBuffer

    public final void setBuffer(QByteArray byteArray)

  Makes the QBuffer use the `byteArray` as its internal buffer.

  Does nothing if isOpen() is true.

  If you open the buffer in write-only mode or read-write mode and write something into the QBuffer, \a byteArray will be modified.

  If `byteArray` is null, the buffer creates its own internal QByteArray to work on. This byte array is initially empty.

### setData

    public final void setData(byte[] data)

  Sets the contents of this QBuffer to `data`

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