java.lang.Object
java.nio.channels.spi.AbstractInterruptibleChannel
java.nio.channels.SelectableChannel
java.nio.channels.spi.AbstractSelectableChannel
java.nio.channels.DatagramChannel
public abstract class DatagramChannel
A selectable channel for datagram-oriented sockets.
Datagram channels are not a complete abstraction of network datagram sockets. Binding and the manipulation of socket options must be done through an associated DatagramSocket object obtained by invoking the socket method. It is not possible to create a channel for an arbitrary, pre-existing datagram socket, nor is it possible to specify the DatagramSocketImpl object to be used by a datagram socket associated with a datagram channel.
A datagram channel is created by invoking the open method of this class. A newly-created datagram channel is open but not connected. A datagram channel need not be connected in order for the send and receive methods to be used. A datagram channel may be connected, by invoking its connect method, in order to avoid the overhead of the security checks are otherwise performed as part of every send and receive operation. A datagram channel must be connected in order to use the read and write methods, since those methods do not accept or return socket addresses.
Once connected, a datagram channel remains connected until it is disconnected or closed. Whether or not a datagram channel is connected may be determined by invoking its isConnected method.
Datagram channels are safe for use by multiple concurrent threads. They support concurrent reading and writing, though at most one thread may be reading and at most one thread may be writing at any given time.
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait DatagramChannel
protected DatagramChannel(SelectorProvider provider)
public static DatagramChannel open()
throws IOException
The new channel is created by invoking the openDatagramChannel method of the system-wide default SelectorProvider object. The channel will not be connected.
IOException - If an I/O error occurs
public final int validOps()
Datagram channels support reading and writing, so this method returns (SelectionKey.OP_READ | SelectionKey.OP_WRITE).
validOps in class SelectableChannel
public abstract DatagramSocket socket()
The returned object will not declare any public methods that are not declared in the DatagramSocket class.
public abstract boolean isConnected()
public abstract DatagramChannel connect(SocketAddress remote)
throws IOException
The channel's socket is configured so that it only receives datagrams from, and sends datagrams to, the given remote peer address. Once connected, datagrams may not be received from or sent to any other address. A datagram socket remains connected until it is explicitly disconnected or until it is closed.
This method performs exactly the same security checks as the connect method of the DatagramSocket class. That is, if a security manager has been installed then this method verifies that its checkAccept and checkConnect methods permit datagrams to be received from and sent to, respectively, the given remote address.
This method may be invoked at any time. It will not have any effect on read or write operations that are already in progress at the moment that it is invoked.
remote - The remote address to which this channel is to be connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the connect operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the connect operation is in progress, thereby closing the channel and setting the current thread's interrupt status
SecurityException - If a security manager has been installed and it does not permit access to the given remote address
IOException - If some other I/O error occurs
public abstract DatagramChannel disconnect()
throws IOException
The channel's socket is configured so that it can receive datagrams from, and sends datagrams to, any remote address so long as the security manager, if installed, permits it.
This method may be invoked at any time. It will not have any effect on read or write operations that are already in progress at the moment that it is invoked.
If this channel's socket is not connected, or if the channel is closed, then invoking this method has no effect.
IOException - If some other I/O error occurs
public abstract SocketAddress receive(ByteBuffer dst)
throws IOException
If a datagram is immediately available, or if this channel is in blocking mode and one eventually becomes available, then the datagram is copied into the given byte buffer and its source address is returned. If this channel is in non-blocking mode and a datagram is not immediately available then this method immediately returns null.
The datagram is transferred into the given byte buffer starting at its current position, as if by a regular read operation. If there are fewer bytes remaining in the buffer than are required to hold the datagram then the remainder of the datagram is silently discarded.
This method performs exactly the same security checks as the receive method of the DatagramSocket class. That is, if the socket is not connected to a specific remote address and a security manager has been installed then for each datagram received this method verifies that the source's address and port number are permitted by the security manager's checkAccept method. The overhead of this security check can be avoided by first connecting the socket via the connect method.
This method may be invoked at any time. If another thread has already initiated a read operation upon this channel, however, then an invocation of this method will block until the first operation is complete.
dst - The buffer into which the datagram is to be transferred
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the read operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status
SecurityException - If a security manager has been installed and it does not permit datagrams to be accepted from the datagram's sender
IOException - If some other I/O error occurs
public abstract int send(ByteBuffer src,
SocketAddress target)
throws IOException
If this channel is in non-blocking mode and there is sufficient room in the underlying output buffer, or if this channel is in blocking mode and sufficient room becomes available, then the remaining bytes in the given buffer are transmitted as a single datagram to the given target address.
The datagram is transferred from the byte buffer as if by a regular write operation.
This method performs exactly the same security checks as the send method of the DatagramSocket class. That is, if the socket is not connected to a specific remote address and a security manager has been installed then for each datagram sent this method verifies that the target address and port number are permitted by the security manager's checkConnect method. The overhead of this security check can be avoided by first connecting the socket via the connect method.
This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.
src - The buffer containing the datagram to be sent
target - The address to which the datagram is to be sent
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the read operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status
SecurityException - If a security manager has been installed and it does not permit datagrams to be sent to the given address
IOException - If some other I/O error occurs
public abstract int read(ByteBuffer dst)
throws IOException
This method may only be invoked if this channel's socket is connected, and it only accepts datagrams from the socket's peer. If there are more bytes in the datagram than remain in the given buffer then the remainder of the datagram is silently discarded. Otherwise this method behaves exactly as specified in the ReadableByteChannel interface.
read in interface ReadableByteChannel
dst - The buffer into which bytes are to be transferred
NotYetConnectedException - If this channel's socket is not connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the read operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status
IOException - If some other I/O error occurs
public abstract long read(ByteBuffer[] dsts,
int offset,
int length)
throws IOException
This method may only be invoked if this channel's socket is connected, and it only accepts datagrams from the socket's peer. If there are more bytes in the datagram than remain in the given buffers then the remainder of the datagram is silently discarded. Otherwise this method behaves exactly as specified in the ScatteringByteChannel interface.
read in interface ScatteringByteChannel
dsts - The buffers into which bytes are to be transferred
offset - The offset within the buffer array of the first buffer into which bytes are to be transferred; must be non-negative and no larger than dsts.length
length - The maximum number of buffers to be accessed; must be non-negative and no larger than dsts.length - offset
NotYetConnectedException - If this channel's socket is not connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the read operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status
IOException - If some other I/O error occurs
public final long read(ByteBuffer[] dsts)
throws IOException
This method may only be invoked if this channel's socket is connected, and it only accepts datagrams from the socket's peer. If there are more bytes in the datagram than remain in the given buffers then the remainder of the datagram is silently discarded. Otherwise this method behaves exactly as specified in the ScatteringByteChannel interface.
read in interface ScatteringByteChannel
dsts - The buffers into which bytes are to be transferred
NotYetConnectedException - If this channel's socket is not connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the read operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the read operation is in progress, thereby closing the channel and setting the current thread's interrupt status
IOException - If some other I/O error occurs
public abstract int write(ByteBuffer src)
throws IOException
This method may only be invoked if this channel's socket is connected, in which case it sends datagrams directly to the socket's peer. Otherwise it behaves exactly as specified in the WritableByteChannel interface.
write in interface WritableByteChannel
src - The buffer from which bytes are to be retrieved
NotYetConnectedException - If this channel's socket is not connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the write operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
IOException - If some other I/O error occurs
public abstract long write(ByteBuffer[] srcs,
int offset,
int length)
throws IOException
This method may only be invoked if this channel's socket is connected, in which case it sends datagrams directly to the socket's peer. Otherwise it behaves exactly as specified in the GatheringByteChannel interface.
write in interface GatheringByteChannel
srcs - The buffers from which bytes are to be retrieved
offset - The offset within the buffer array of the first buffer from which bytes are to be retrieved; must be non-negative and no larger than srcs.length
length - The maximum number of buffers to be accessed; must be non-negative and no larger than srcs.length - offset
NotYetConnectedException - If this channel's socket is not connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the write operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
IOException - If some other I/O error occurs
public final long write(ByteBuffer[] srcs)
throws IOException
This method may only be invoked if this channel's socket is connected, in which case it sends datagrams directly to the socket's peer. Otherwise it behaves exactly as specified in the GatheringByteChannel interface.
write in interface GatheringByteChannel
srcs - The buffers from which bytes are to be retrieved
NotYetConnectedException - If this channel's socket is not connected
ClosedChannelException - If this channel is closed
AsynchronousCloseException - If another thread closes this channel while the write operation is in progress
ClosedByInterruptException - If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
IOException - If some other I/O error occurs
Copyright © 2004, 2010 Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4