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java.lang.Objectcom.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.core.QObject
com.trolltech.qt.core.QIODevice
com.trolltech.qt.network.QAbstractSocket
public class QAbstractSocket
The QAbstractSocket class provides the base functionality common to all socket types. QAbstractSocket is the base class for QTcpSocket
and QUdpSocket
and contains all common functionality of these two classes. If you need a socket, you have two options:
QTcpSocket
or QUdpSocket
.setSocketDescriptor()
to wrap the native socket.QAbstractSocket's API unifies most of the differences between the two protocols. For example, although UDP is connectionless, connectToHost()
establishes a virtual connection for UDP sockets, enabling you to use QAbstractSocket in more or less the same way regardless of the underlying protocol. Internally, QAbstractSocket remembers the address and port passed to connectToHost()
, and functions like read()
and write()
use these values.
At any time, QAbstractSocket has a state (returned by state()
). The initial state is UnconnectedState
. After calling connectToHost()
, the socket first enters HostLookupState
. If the host is found, QAbstractSocket enters ConnectingState
and emits the hostFound()
signal. When the connection has been established, it enters ConnectedState
and emits connected()
. If an error occurs at any stage, error()
is emitted. Whenever the state changes, stateChanged()
is emitted. For convenience, isValid()
returns true if the socket is ready for reading and writing, but note that the socket's state must be ConnectedState
before reading and writing can occur.
Read or write data by calling read()
or write()
, or use the convenience functions readLine()
and readAll()
. QAbstractSocket also inherits getChar(), putChar(), and ungetChar() from QIODevice
, which work on single bytes. For every chunk of data that has been written to the socket, the bytesWritten()
signal is emitted.
The readyRead()
signal is emitted every time a new chunk of data has arrived. bytesAvailable() then returns the number of bytes that are available for reading. Typically, you would connect the readyRead()
signal to a slot and read all available data there. If you don't read all the data at once, the remaining data will still be available later, and any new incoming data will be appended to QAbstractSocket's internal read buffer. To limit the size of the read buffer, call setReadBufferSize()
.
To close the socket, call disconnectFromHost()
. QAbstractSocket enters QAbstractSocket::ClosingState
, then emits closing(). After all pending data has been written to the socket, QAbstractSocket actually closes the socket, enters QAbstractSocket::ClosedState, and emits disconnected()
. If you want to abort a connection immediately, discarding all pending data, call abort()
instead. If the remote host closes the connection, QAbstractSocket will emit error(QAbstractSocket::RemoteHostClosedError
), during which the socket state will still be ConnectedState
, and then the disconnected()
signal will be emitted.
The port and address of the connected peer is fetched by calling peerPort()
and peerAddress()
. peerName()
returns the host name of the peer, as passed to connectToHost()
. localPort()
and localAddress()
return the port and address of the local socket.
QAbstractSocket provides a set of functions that suspend the calling thread until certain signals are emitted. These functions can be used to implement blocking sockets:
waitForConnected()
blocks until a connection has been established.waitForBytesWritten()
blocks until one payload of data has been written to the socket.waitForDisconnected()
blocks until the connection has closed.int numRead = 0, numReadTotal = 0; byte buffer[] = new byte[50]; while (true) { numRead = socket.read(buffer); // do whatever with array numReadTotal += numRead; if (numRead == 0 && !socket.waitForReadyRead(1000)) break; }If
waitForReadyRead()
returns false, the connection has been closed or an error has occurred. Programming with a blocking socket is radically different from programming with a non-blocking socket. A blocking socket doesn't require an event loop and typically leads to simpler code. However, in a GUI application, blocking sockets should only be used in non-GUI threads, to avoid freezing the user interface. See the network/fortuneclient and network/blockingfortuneclient examples for an overview of both approaches.
QAbstractSocket can be used with QTextStream
and QDataStream
's stream operators (operator<<() and operator>>()). There is one issue to be aware of, though: You must make sure that enough data is available before attempting to read it using operator>>().
QFtp
, QHttp
, and QTcpServer
.
Nested Class Summary | |
---|---|
static class |
QAbstractSocket.NetworkLayerProtocol
This enum describes the network layer protocol values used in Qt. |
static class |
QAbstractSocket.SocketError
This enum describes the socket errors that can occur. |
static class |
QAbstractSocket.SocketState
This enum describes the different states in which a socket can be. |
static class |
QAbstractSocket.SocketType
This enum describes the transport layer protocol. |
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.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 | |
---|---|
QSignalEmitter.Signal0 |
connected
This signal is emitted after connectToHost() has been called and a connection has been successfully established. |
QSignalEmitter.Signal0 |
disconnected
This signal is emitted when the socket has been disconnected. |
QSignalEmitter.Signal1 |
error
This signal takes 1 generic argument(s). |
QSignalEmitter.Signal0 |
hostFound
This signal is emitted after connectToHost() has been called and the host lookup has succeeded. |
QSignalEmitter.Signal2 |
proxyAuthenticationRequired
This signal takes 2 generic argument(s). |
QSignalEmitter.Signal1 |
stateChanged
This signal takes 1 generic argument(s). |
Fields inherited from class com.trolltech.qt.core.QIODevice |
---|
aboutToClose, bytesWritten, readChannelFinished, readyRead |
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
---|
currentSender |
Constructor Summary | |
---|---|
QAbstractSocket(QAbstractSocket.SocketType socketType,
QObject parent)
Creates a new abstract socket of type socketType. |
Method Summary | |
---|---|
void |
abort()
Aborts the current connection and resets the socket. |
void |
connectToHost(QHostAddress host,
int port)
Attempts to make a connection to address on port port. |
void |
connectToHost(QHostAddress host,
int port,
QIODevice.OpenMode mode)
Attempts to make a connection to address on port port. |
void |
connectToHost(QHostAddress host,
int port,
QIODevice.OpenModeFlag[] mode)
Attempts to make a connection to address on port port. |
void |
connectToHost(java.lang.String host,
int port)
Attempts to make a connection to hostName on the given port. |
void |
connectToHost(java.lang.String host,
int port,
QIODevice.OpenMode mode)
Attempts to make a connection to hostName on the given port. |
void |
connectToHost(java.lang.String host,
int port,
QIODevice.OpenModeFlag[] mode)
Attempts to make a connection to hostName on the given port. |
void |
disconnectFromHost()
Attempts to close the socket. |
protected void |
disconnectFromHostImplementation()
Contains the implementation of disconnectFromHost() . |
QAbstractSocket.SocketError |
error()
Returns the type of error that last occurred. |
boolean |
flush()
This function writes as much as possible from the internal write buffer to the underlying network socket, without blocking. |
boolean |
isValid()
Returns true if the socket is valid and ready for use; otherwise returns false. |
QHostAddress |
localAddress()
Returns the host address of the local socket if available; otherwise returns QHostAddress::Null . |
int |
localPort()
Returns the host port number (in native byte order) of the local socket if available; otherwise returns 0. |
QHostAddress |
peerAddress()
Returns the address of the connected peer if the socket is in ConnectedState ; otherwise returns QHostAddress::Null . |
java.lang.String |
peerName()
Returns the name of the peer as specified by connectToHost() , or an empty QString if connectToHost() has not been called. |
int |
peerPort()
Returns the port of the connected peer if the socket is in ConnectedState; otherwise returns 0. |
QNetworkProxy |
proxy()
Returns the network proxy for this socket. |
long |
readBufferSize()
Returns the size of the internal read buffer. |
protected void |
setLocalAddress(QHostAddress address)
Sets the address on the local side of a connection to address. |
protected void |
setLocalPort(int port)
Sets the local port of this QAbstractSocket to port. |
protected void |
setPeerAddress(QHostAddress address)
Sets the address of the remote side of the connection to address. |
protected void |
setPeerName(java.lang.String name)
Sets the host name of the remote peer to name. |
protected void |
setPeerPort(int port)
Sets the peer port of this QAbstractSocket to port. |
void |
setProxy(QNetworkProxy networkProxy)
Sets the explicit network proxy for this socket to networkProxy. |
void |
setReadBufferSize(long size)
Sets the size of QAbstractSocket's internal read buffer to be size bytes. |
boolean |
setSocketDescriptor(int socketDescriptor)
Initializes QAbstractSocket with the native socket descriptor socketDescriptor. |
boolean |
setSocketDescriptor(int socketDescriptor,
QAbstractSocket.SocketState state)
Initializes QAbstractSocket with the native socket descriptor socketDescriptor. |
boolean |
setSocketDescriptor(int socketDescriptor,
QAbstractSocket.SocketState state,
QIODevice.OpenMode openMode)
Initializes QAbstractSocket with the native socket descriptor socketDescriptor. |
boolean |
setSocketDescriptor(int socketDescriptor,
QAbstractSocket.SocketState state,
QIODevice.OpenModeFlag[] openMode)
|
protected void |
setSocketError(QAbstractSocket.SocketError socketError)
Sets the type of error that last occurred to socketError. |
protected void |
setSocketState(QAbstractSocket.SocketState state)
Sets the state of the socket to state. |
int |
socketDescriptor()
Returns the native socket descriptor of the QAbstractSocket object if this is available; otherwise returns -1. |
QAbstractSocket.SocketType |
socketType()
Returns the socket type (TCP, UDP, or other). |
QAbstractSocket.SocketState |
state()
Returns the state of the socket. |
boolean |
waitForConnected()
Waits until the socket is connected, up to msecs milliseconds. |
boolean |
waitForConnected(int msecs)
Waits until the socket is connected, up to msecs milliseconds. |
boolean |
waitForDisconnected()
Waits until the socket has disconnected, up to msecs milliseconds. |
boolean |
waitForDisconnected(int msecs)
Waits until the socket has disconnected, up to msecs milliseconds. |
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 com.trolltech.qt.internal.QSignalEmitterInternal |
---|
__qt_signalInitialization |
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 |
Field Detail |
---|
public final QSignalEmitter.Signal0 connected
connectToHost()
has been called and a connection has been successfully established. connectToHost()
, and disconnected()
.
public final QSignalEmitter.Signal0 disconnected
Warning: If you need to delete the sender() of this signal in a slot connected to it, use the deleteLater() function.
connectToHost()
, disconnectFromHost()
, and abort()
.
public final QSignalEmitter.Signal1 error
This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.network.QAbstractSocket$SocketError(named: socketError)>:
This signal is emitted after an error occurred. The socketError parameter describes the type of error that occurred.
QAbstractSocket::SocketError
is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE.
error()
, and errorString()
.
public final QSignalEmitter.Signal0 hostFound
connectToHost()
has been called and the host lookup has succeeded. connected()
.
public final QSignalEmitter.Signal1 stateChanged
This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.network.QAbstractSocket$SocketState(named: socketState)>:
This signal is emitted whenever QAbstractSocket's state changes. The socketState parameter is the new state.
QAbstractSocket::SocketState
is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE.
state()
.
public QSignalEmitter.Signal2 proxyAuthenticationRequired
This signal takes 2 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.network.QNetworkProxy(named: proxy), com.trolltech.qt.network.QAuthenticator(named: authenticator)>:
This signal can be emitted when a proxy that requires authentication is used. The authenticator object can then be filled in with the required details to allow authentication and continue the connection.
Note: It is not possible to use a QueuedConnection to connect to this signal, as the connection will fail if the authenticator has not been filled in with new information when the signal returns.
QAuthenticator
, and QNetworkProxy
.
Constructor Detail |
---|
public QAbstractSocket(QAbstractSocket.SocketType socketType, QObject parent)
QObject
's constructor. socketType()
, QTcpSocket
, and QUdpSocket
.
Method Detail |
---|
public void abort()
disconnectFromHost()
, this function immediately closes the socket, discarding any pending data in the write buffer. disconnectFromHost()
, and close().
public final void disconnectFromHost()
ClosingState
and wait until all data has been written. Eventually, it will enter UnconnectedState
and emit the disconnected()
signal. connectToHost()
.
protected void disconnectFromHostImplementation()
disconnectFromHost()
.
public final QAbstractSocket.SocketError error()
state()
, and errorString()
.
public boolean flush()
Call this function if you need QAbstractSocket to start sending buffered data immediately. The number of bytes successfully written depends on the operating system. In most cases, you do not need to call this function, because QAbstractSocket will start sending data automatically once control goes back to the event loop. In the absence of an event loop, call waitForBytesWritten()
instead.
write()
, and waitForBytesWritten()
.
public final boolean isValid()
Note: The socket's state must be ConnectedState
before reading and writing can occur.
state()
.
public final QHostAddress localAddress()
QHostAddress::Null
. This is normally the main IP address of the host, but can be QHostAddress::LocalHost
(127.0.0.1) for connections to the local host.
localPort()
, peerAddress()
, and setLocalAddress()
.
public final QHostAddress peerAddress()
ConnectedState
; otherwise returns QHostAddress::Null
. peerName()
, peerPort()
, localAddress()
, and setPeerAddress()
.
public final java.lang.String peerName()
connectToHost()
, or an empty QString if connectToHost()
has not been called. peerAddress()
, peerPort()
, and setPeerName()
.
public final QNetworkProxy proxy()
QNetworkProxy::DefaultProxy
is used. setProxy()
, and QNetworkProxy
.
public final long readBufferSize()
read()
or readAll()
. A read buffer size of 0 (the default) means that the buffer has no size limit, ensuring that no data is lost.
setReadBufferSize()
, and read()
.
protected final void setLocalAddress(QHostAddress address)
You can call this function in a subclass of QAbstractSocket to change the return value of the localAddress()
function after a connection has been established. This feature is commonly used by proxy connections for virtual connection settings.
Note that this function does not bind the local address of the socket prior to a connection (e.g., QUdpSocket::bind()
).
localAddress()
, setLocalPort()
, and setPeerAddress()
.
protected final void setPeerAddress(QHostAddress address)
You can call this function in a subclass of QAbstractSocket to change the return value of the peerAddress()
function after a connection has been established. This feature is commonly used by proxy connections for virtual connection settings.
peerAddress()
, setPeerPort()
, and setLocalAddress()
.
protected final void setPeerName(java.lang.String name)
You can call this function in a subclass of QAbstractSocket to change the return value of the peerName()
function after a connection has been established. This feature is commonly used by proxy connections for virtual connection settings.
peerName()
.
public final void setProxy(QNetworkProxy networkProxy)
To disable the use of a proxy for this socket, use the QNetworkProxy::NoProxy
proxy type:
The following code example is written in c++.
socket->setProxy(QNetworkProxy::NoProxy);
proxy()
, and QNetworkProxy
.
public void setReadBufferSize(long size)
If the buffer size is limited to a certain size, QAbstractSocket won't buffer more than this size of data. Exceptionally, a buffer size of 0 means that the read buffer is unlimited and all incoming data is buffered. This is the default.
This option is useful if you only read the data at certain points in time (e.g., in a real-time streaming application) or if you want to protect your socket against receiving too much data, which may eventually cause your application to run out of memory.
Only QTcpSocket
uses QAbstractSocket's internal buffer; QUdpSocket
does not use any buffering at all, but rather relies on the implicit buffering provided by the operating system. Because of this, calling this function on QUdpSocket
has no effect.
readBufferSize()
, and read()
.
public final boolean setSocketDescriptor(int socketDescriptor, QAbstractSocket.SocketState state, QIODevice.OpenModeFlag[] openMode)
public final boolean setSocketDescriptor(int socketDescriptor, QAbstractSocket.SocketState state)
Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.
socketDescriptor()
.
public final boolean setSocketDescriptor(int socketDescriptor)
Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.
socketDescriptor()
.
public boolean setSocketDescriptor(int socketDescriptor, QAbstractSocket.SocketState state, QIODevice.OpenMode openMode)
Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.
socketDescriptor()
.
protected final void setSocketError(QAbstractSocket.SocketError socketError)
setSocketState()
, and setErrorString()
.
protected final void setSocketState(QAbstractSocket.SocketState state)
state()
.
public final int socketDescriptor()
If the socket is using QNetworkProxy
, the returned descriptor may not be usable with native socket functions.
The socket descriptor is not available when QAbstractSocket is in UnconnectedState
.
setSocketDescriptor()
.
public final QAbstractSocket.SocketType socketType()
QTcpSocket
, and QUdpSocket
.
public final QAbstractSocket.SocketState state()
error()
.
public final boolean waitForConnected()
error()
to determine the cause of the error. The following example waits up to one second for a connection to be established:
The following code example is written in c++.
socket->connectToHost("imap", 143); if (socket->waitForConnected(1000)) qDebug("Connected!");If msecs is -1, this function will not time out.
Note: This function may wait slightly longer than msecs, depending on the time it takes to complete the host lookup.
connectToHost()
, and connected()
.
public boolean waitForConnected(int msecs)
error()
to determine the cause of the error. The following example waits up to one second for a connection to be established:
The following code example is written in c++.
socket->connectToHost("imap", 143); if (socket->waitForConnected(1000)) qDebug("Connected!");If msecs is -1, this function will not time out.
Note: This function may wait slightly longer than msecs, depending on the time it takes to complete the host lookup.
connectToHost()
, and connected()
.
public final boolean waitForDisconnected()
error()
to determine the cause of the error. The following example waits up to one second for a connection to be closed:
The following code example is written in c++.
socket->disconnectFromHost(); if (socket->state() == QAbstractSocket::UnconnectedState || socket->waitForDisconnected(1000)) qDebug("Disconnected!");If msecs is -1, this function will not time out.
disconnectFromHost()
, and close().
public boolean waitForDisconnected(int msecs)
error()
to determine the cause of the error. The following example waits up to one second for a connection to be closed:
The following code example is written in c++.
socket->disconnectFromHost(); if (socket->state() == QAbstractSocket::UnconnectedState || socket->waitForDisconnected(1000)) qDebug("Disconnected!");If msecs is -1, this function will not time out.
disconnectFromHost()
, and close().
public final void connectToHost(java.lang.String host, int port, QIODevice.OpenMode mode)
The socket is opened in the given openMode and first enters HostLookupState
, then performs a host name lookup of hostName. If the lookup succeeds, hostFound()
is emitted and QAbstractSocket enters ConnectingState
. It then attempts to connect to the address or addresses returned by the lookup. Finally, if a connection is established, QAbstractSocket enters ConnectedState
and emits connected()
.
At any point, the socket can emit error()
to signal that an error occurred.
hostName may be an IP address in string form (e.g., "43.195.83.32"), or it may be a host name (e.g., "www.trolltech.com"). QAbstractSocket will do a lookup only if required. port is in native byte order.
state()
, peerName()
, peerAddress()
, peerPort()
, and waitForConnected()
.
public final void connectToHost(java.lang.String host, int port, QIODevice.OpenModeFlag[] mode)
The socket is opened in the given openMode and first enters HostLookupState
, then performs a host name lookup of hostName. If the lookup succeeds, hostFound()
is emitted and QAbstractSocket enters ConnectingState
. It then attempts to connect to the address or addresses returned by the lookup. Finally, if a connection is established, QAbstractSocket enters ConnectedState
and emits connected()
.
At any point, the socket can emit error()
to signal that an error occurred.
hostName may be an IP address in string form (e.g., "43.195.83.32"), or it may be a host name (e.g., "www.trolltech.com"). QAbstractSocket will do a lookup only if required. port is in native byte order.
state()
, peerName()
, peerAddress()
, peerPort()
, and waitForConnected()
.
public final void connectToHost(java.lang.String host, int port)
The socket is opened in the given openMode and first enters HostLookupState
, then performs a host name lookup of hostName. If the lookup succeeds, hostFound()
is emitted and QAbstractSocket enters ConnectingState
. It then attempts to connect to the address or addresses returned by the lookup. Finally, if a connection is established, QAbstractSocket enters ConnectedState
and emits connected()
.
At any point, the socket can emit error()
to signal that an error occurred.
hostName may be an IP address in string form (e.g., "43.195.83.32"), or it may be a host name (e.g., "www.trolltech.com"). QAbstractSocket will do a lookup only if required. port is in native byte order.
state()
, peerName()
, peerAddress()
, peerPort()
, and waitForConnected()
.
public final void connectToHost(QHostAddress host, int port, QIODevice.OpenMode mode)
public final void connectToHost(QHostAddress host, int port, QIODevice.OpenModeFlag[] mode)
public final void connectToHost(QHostAddress host, int port)
public final int localPort()
public final int peerPort()
protected final void setLocalPort(int port)
protected final void setPeerPort(int port)
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