File	Doc	Category	Size	Date	Package
DatagramChannel.java	API Doc	Java SE 5 API	17402	Fri Aug 26 14:57:10 BST 2005	java.nio.channels

DatagramChannel

• java.lang.Object
  • java.nio.channels.spi.AbstractInterruptibleChannel
    • java.nio.channels.SelectableChannel
      • java.nio.channels.spi.AbstractSelectableChannel

Fields Summary

Constructors Summary
protected DatagramChannel(SelectorProvider provider) Initializes a new instance of this class. super(provider);

Methods Summary
public abstract java.nio.channels.DatagramChannel	connect(java.net.SocketAddress remote) Connects this channel's socket. 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 {@link java.net.DatagramSocket#connect connect} method of the {@link java.net.DatagramSocket} class. That is, if a security manager has been installed then this method verifies that its {@link java.lang.SecurityManager#checkAccept checkAccept} and {@link java.lang.SecurityManager#checkConnect 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. param remote The remote address to which this channel is to be connected return This datagram channel throws ClosedChannelException If this channel is closed throws AsynchronousCloseException If another thread closes this channel while the connect operation is in progress throws 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 throws SecurityException If a security manager has been installed and it does not permit access to the given remote address throws IOException If some other I/O error occurs
public abstract java.nio.channels.DatagramChannel	disconnect() Disconnects this channel's socket. 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. return This datagram channel throws IOException If some other I/O error occurs
public abstract boolean	isConnected() Tells whether or not this channel's socket is connected. return true if, and only if, this channel's socket is connected
public static java.nio.channels.DatagramChannel	open() Opens a datagram channel. The new channel is created by invoking the {@link java.nio.channels.spi.SelectorProvider#openDatagramChannel() openDatagramChannel} method of the system-wide default {@link java.nio.channels.spi.SelectorProvider} object. The channel will not be connected. return A new datagram channel throws IOException If an I/O error occurs return SelectorProvider.provider().openDatagramChannel();
public abstract int	read(java.nio.ByteBuffer dst) Reads a datagram from this channel. 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 {@link ReadableByteChannel} interface. throws NotYetConnectedException If this channel's socket is not connected
public abstract long	read(java.nio.ByteBuffer[] dsts, int offset, int length) Reads a datagram from this channel. 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 {@link ScatteringByteChannel} interface. throws NotYetConnectedException If this channel's socket is not connected
public final long	read(java.nio.ByteBuffer[] dsts) Reads a datagram from this channel. 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 {@link ScatteringByteChannel} interface. throws NotYetConnectedException If this channel's socket is not connected return read(dsts, 0, dsts.length);
public abstract java.net.SocketAddress	receive(java.nio.ByteBuffer dst) Receives a datagram via this channel. 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 {@link ReadableByteChannel#read(java.nio.ByteBuffer) 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 {@link java.net.DatagramSocket#receive receive} method of the {@link java.net.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 {@link java.lang.SecurityManager#checkAccept checkAccept} method. The overhead of this security check can be avoided by first connecting the socket via the {@link #connect 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. param dst The buffer into which the datagram is to be transferred return The datagram's source address, or null if this channel is in non-blocking mode and no datagram was immediately available throws ClosedChannelException If this channel is closed throws AsynchronousCloseException If another thread closes this channel while the read operation is in progress throws 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 throws SecurityException If a security manager has been installed and it does not permit datagrams to be accepted from the datagram's sender throws IOException If some other I/O error occurs
public abstract int	send(java.nio.ByteBuffer src, java.net.SocketAddress target) Sends a datagram via this channel. 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 {@link WritableByteChannel#write(java.nio.ByteBuffer) write} operation. This method performs exactly the same security checks as the {@link java.net.DatagramSocket#send send} method of the {@link java.net.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 {@link java.lang.SecurityManager#checkConnect checkConnect} method. The overhead of this security check can be avoided by first connecting the socket via the {@link #connect 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. param src The buffer containing the datagram to be sent param target The address to which the datagram is to be sent return The number of bytes sent, which will be either the number of bytes that were remaining in the source buffer when this method was invoked or, if this channel is non-blocking, may be zero if there was insufficient room for the datagram in the underlying output buffer throws ClosedChannelException If this channel is closed throws AsynchronousCloseException If another thread closes this channel while the read operation is in progress throws 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 throws SecurityException If a security manager has been installed and it does not permit datagrams to be sent to the given address throws IOException If some other I/O error occurs
public abstract java.net.DatagramSocket	socket() Retrieves a datagram socket associated with this channel. The returned object will not declare any public methods that are not declared in the {@link java.net.DatagramSocket} class. return A datagram socket associated with this channel
public final int	validOps() Returns an operation set identifying this channel's supported operations. Datagram channels support reading and writing, so this method returns ({@link SelectionKey#OP_READ} | {@link SelectionKey#OP_WRITE}). return The valid-operation set return (SelectionKey.OP_READ | SelectionKey.OP_WRITE);
public abstract int	write(java.nio.ByteBuffer src) Writes a datagram to this channel. 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 {@link WritableByteChannel} interface. throws NotYetConnectedException If this channel's socket is not connected
public abstract long	write(java.nio.ByteBuffer[] srcs, int offset, int length) Writes a datagram to this channel. 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 {@link GatheringByteChannel} interface. return The number of bytes sent, which will be either the number of bytes that were remaining in the source buffer when this method was invoked or, if this channel is non-blocking, may be zero if there was insufficient room for the datagram in the underlying output buffer throws NotYetConnectedException If this channel's socket is not connected
public final long	write(java.nio.ByteBuffer[] srcs) Writes a datagram to this channel. 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 {@link GatheringByteChannel} interface. return The number of bytes sent, which will be either the number of bytes that were remaining in the source buffer when this method was invoked or, if this channel is non-blocking, may be zero if there was insufficient room for the datagram in the underlying output buffer throws NotYetConnectedException If this channel's socket is not connected return write(srcs, 0, srcs.length);