Back to index...

	/*
	* Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.net;

	import java.io.FileDescriptor;
	import java.io.IOException;
	import java.util.Set;

	/**
	* Abstract datagram and multicast socket implementation base class.
	* @author Pavani Diwanji
	* @since 1.1
	*/

	public abstract class DatagramSocketImpl implements SocketOptions {

	/**
	* The local port number.
	*/
	protected int localPort;

	/**
	* The file descriptor object.
	*/
	protected FileDescriptor fd;

	/**
	* The DatagramSocket or MulticastSocket
	* that owns this impl
	*/
	DatagramSocket socket;

	void setDatagramSocket(DatagramSocket socket) {
	this.socket = socket;
	}

	DatagramSocket getDatagramSocket() {
	return socket;
	}

	int dataAvailable() {
	// default impl returns zero, which disables the calling
	// functionality
	return 0;
	}

	/**
	* Creates a datagram socket.
	* @exception SocketException if there is an error in the
	* underlying protocol, such as a TCP error.
	*/
	protected abstract void create() throws SocketException;

	/**
	* Binds a datagram socket to a local port and address.
	* @param lport the local port
	* @param laddr the local address
	* @exception SocketException if there is an error in the
	* underlying protocol, such as a TCP error.
	*/
	protected abstract void bind(int lport, InetAddress laddr) throws SocketException;

	/**
	* Sends a datagram packet. The packet contains the data and the
	* destination address to send the packet to.
	* @param p the packet to be sent.
	* @exception IOException if an I/O exception occurs while sending the
	* datagram packet.
	* @exception PortUnreachableException may be thrown if the socket is connected
	* to a currently unreachable destination. Note, there is no guarantee that
	* the exception will be thrown.
	*/
	protected abstract void send(DatagramPacket p) throws IOException;

	/**
	* Connects a datagram socket to a remote destination. This associates the remote
	* address with the local socket so that datagrams may only be sent to this destination
	* and received from this destination. This may be overridden to call a native
	* system connect.
	*
	* <p>If the remote destination to which the socket is connected does not
	* exist, or is otherwise unreachable, and if an ICMP destination unreachable
	* packet has been received for that address, then a subsequent call to
	* send or receive may throw a PortUnreachableException.
	* Note, there is no guarantee that the exception will be thrown.
	* @param address the remote InetAddress to connect to
	* @param port the remote port number
	* @exception SocketException may be thrown if the socket cannot be
	* connected to the remote destination
	* @since 1.4
	*/
	protected void connect(InetAddress address, int port) throws SocketException {}

	/**
	* Disconnects a datagram socket from its remote destination.
	* @since 1.4
	*/
	protected void disconnect() {}

	/**
	* Peek at the packet to see who it is from. Updates the specified {@code InetAddress}
	* to the address which the packet came from.
	* @param i an InetAddress object
	* @return the port number which the packet came from.
	* @exception IOException if an I/O exception occurs
	* @exception PortUnreachableException may be thrown if the socket is connected
	* to a currently unreachable destination. Note, there is no guarantee that the
	* exception will be thrown.
	*/
	protected abstract int peek(InetAddress i) throws IOException;

	/**
	* Peek at the packet to see who it is from. The data is copied into the specified
	* {@code DatagramPacket}. The data is returned,
	* but not consumed, so that a subsequent peekData/receive operation
	* will see the same data.
	* @param p the Packet Received.
	* @return the port number which the packet came from.
	* @exception IOException if an I/O exception occurs
	* @exception PortUnreachableException may be thrown if the socket is connected
	* to a currently unreachable destination. Note, there is no guarantee that the
	* exception will be thrown.
	* @since 1.4
	*/
	protected abstract int peekData(DatagramPacket p) throws IOException;
	/**
	* Receive the datagram packet.
	* @param p the Packet Received.
	* @exception IOException if an I/O exception occurs
	* while receiving the datagram packet.
	* @exception PortUnreachableException may be thrown if the socket is connected
	* to a currently unreachable destination. Note, there is no guarantee that the
	* exception will be thrown.
	*/
	protected abstract void receive(DatagramPacket p) throws IOException;

	/**
	* Set the TTL (time-to-live) option.
	* @param ttl a byte specifying the TTL value
	*
	* @deprecated use setTimeToLive instead.
	* @exception IOException if an I/O exception occurs while setting
	* the time-to-live option.
	* @see #getTTL()
	*/
	@Deprecated
	protected abstract void setTTL(byte ttl) throws IOException;

	/**
	* Retrieve the TTL (time-to-live) option.
	*
	* @exception IOException if an I/O exception occurs
	* while retrieving the time-to-live option
	* @deprecated use getTimeToLive instead.
	* @return a byte representing the TTL value
	* @see #setTTL(byte)
	*/
	@Deprecated
	protected abstract byte getTTL() throws IOException;

	/**
	* Set the TTL (time-to-live) option.
	* @param ttl an {@code int} specifying the time-to-live value
	* @exception IOException if an I/O exception occurs
	* while setting the time-to-live option.
	* @see #getTimeToLive()
	*/
	protected abstract void setTimeToLive(int ttl) throws IOException;

	/**
	* Retrieve the TTL (time-to-live) option.
	* @exception IOException if an I/O exception occurs
	* while retrieving the time-to-live option
	* @return an {@code int} representing the time-to-live value
	* @see #setTimeToLive(int)
	*/
	protected abstract int getTimeToLive() throws IOException;

	/**
	* Join the multicast group.
	* @param inetaddr multicast address to join.
	* @exception IOException if an I/O exception occurs
	* while joining the multicast group.
	*/
	protected abstract void join(InetAddress inetaddr) throws IOException;

	/**
	* Leave the multicast group.
	* @param inetaddr multicast address to leave.
	* @exception IOException if an I/O exception occurs
	* while leaving the multicast group.
	*/
	protected abstract void leave(InetAddress inetaddr) throws IOException;

	/**
	* Join the multicast group.
	* @param mcastaddr address to join.
	* @param netIf specifies the local interface to receive multicast
	* datagram packets
	* @throws IOException if an I/O exception occurs while joining
	* the multicast group
	* @since 1.4
	*/
	protected abstract void joinGroup(SocketAddress mcastaddr,
	NetworkInterface netIf)
	throws IOException;

	/**
	* Leave the multicast group.
	* @param mcastaddr address to leave.
	* @param netIf specified the local interface to leave the group at
	* @throws IOException if an I/O exception occurs while leaving
	* the multicast group
	* @since 1.4
	*/
	protected abstract void leaveGroup(SocketAddress mcastaddr,
	NetworkInterface netIf)
	throws IOException;

	/**
	* Close the socket.
	*/
	protected abstract void close();

	/**
	* Gets the local port.
	* @return an {@code int} representing the local port value
	*/
	protected int getLocalPort() {
	return localPort;
	}

	/**
	* Gets the datagram socket file descriptor.
	* @return a {@code FileDescriptor} object representing the datagram socket
	* file descriptor
	*/
	protected FileDescriptor getFileDescriptor() {
	return fd;
	}

	/**
	* Called to set a socket option.
	*
	* @param <T> The type of the socket option value
	* @param name The socket option
	*
	* @param value The value of the socket option. A value of {@code null}
	* may be valid for some options.
	*
	* @throws UnsupportedOperationException if the DatagramSocketImpl does not
	* support the option
	*
	* @throws NullPointerException if name is {@code null}
	* @throws IOException if an I/O problem occurs while attempting to set the option
	* @since 9
	*/
	protected <T> void setOption(SocketOption<T> name, T value) throws IOException {
	if (name == StandardSocketOptions.SO_SNDBUF) {
	setOption(SocketOptions.SO_SNDBUF, value);
	} else if (name == StandardSocketOptions.SO_RCVBUF) {
	setOption(SocketOptions.SO_RCVBUF, value);
	} else if (name == StandardSocketOptions.SO_REUSEADDR) {
	setOption(SocketOptions.SO_REUSEADDR, value);
	} else if (name == StandardSocketOptions.SO_REUSEPORT &&
	supportedOptions().contains(name)) {
	setOption(SocketOptions.SO_REUSEPORT, value);
	} else if (name == StandardSocketOptions.IP_TOS) {
	setOption(SocketOptions.IP_TOS, value);
	} else if (name == StandardSocketOptions.IP_MULTICAST_IF &&
	(getDatagramSocket() instanceof MulticastSocket)) {
	setOption(SocketOptions.IP_MULTICAST_IF2, value);
	} else if (name == StandardSocketOptions.IP_MULTICAST_TTL &&
	(getDatagramSocket() instanceof MulticastSocket)) {
	if (! (value instanceof Integer)) {
	throw new IllegalArgumentException("not an integer");
	}
	setTimeToLive((Integer)value);
	} else if (name == StandardSocketOptions.IP_MULTICAST_LOOP &&
	(getDatagramSocket() instanceof MulticastSocket)) {
	setOption(SocketOptions.IP_MULTICAST_LOOP, value);
	} else {
	throw new UnsupportedOperationException("unsupported option");
	}
	}

	/**
	* Called to get a socket option.
	*
	* @return the socket option
	* @param <T> The type of the socket option value
	* @param name The socket option
	*
	* @throws UnsupportedOperationException if the DatagramSocketImpl does not
	* support the option
	*
	* @throws NullPointerException if name is {@code null}
	* @throws IOException if an I/O problem occurs while attempting to set the option
	*
	* @since 9
	*/
	@SuppressWarnings("unchecked")
	protected <T> T getOption(SocketOption<T> name) throws IOException {
	if (name == StandardSocketOptions.SO_SNDBUF) {
	return (T) getOption(SocketOptions.SO_SNDBUF);
	} else if (name == StandardSocketOptions.SO_RCVBUF) {
	return (T) getOption(SocketOptions.SO_RCVBUF);
	} else if (name == StandardSocketOptions.SO_REUSEADDR) {
	return (T) getOption(SocketOptions.SO_REUSEADDR);
	} else if (name == StandardSocketOptions.SO_REUSEPORT &&
	supportedOptions().contains(name)) {
	return (T) getOption(SocketOptions.SO_REUSEPORT);
	} else if (name == StandardSocketOptions.IP_TOS) {
	return (T) getOption(SocketOptions.IP_TOS);
	} else if (name == StandardSocketOptions.IP_MULTICAST_IF &&
	(getDatagramSocket() instanceof MulticastSocket)) {
	return (T) getOption(SocketOptions.IP_MULTICAST_IF2);
	} else if (name == StandardSocketOptions.IP_MULTICAST_TTL &&
	(getDatagramSocket() instanceof MulticastSocket)) {
	Integer ttl = getTimeToLive();
	return (T)ttl;
	} else if (name == StandardSocketOptions.IP_MULTICAST_LOOP &&
	(getDatagramSocket() instanceof MulticastSocket)) {
	return (T) getOption(SocketOptions.IP_MULTICAST_LOOP);
	} else {
	throw new UnsupportedOperationException("unsupported option");
	}
	}

	private static final Set<SocketOption<?>> dgSocketOptions;

	private static final Set<SocketOption<?>> mcSocketOptions;

	static {
	dgSocketOptions = Set.of(StandardSocketOptions.SO_SNDBUF,
	StandardSocketOptions.SO_RCVBUF,
	StandardSocketOptions.SO_REUSEADDR,
	StandardSocketOptions.IP_TOS);

	mcSocketOptions = Set.of(StandardSocketOptions.SO_SNDBUF,
	StandardSocketOptions.SO_RCVBUF,
	StandardSocketOptions.SO_REUSEADDR,
	StandardSocketOptions.IP_TOS,
	StandardSocketOptions.IP_MULTICAST_IF,
	StandardSocketOptions.IP_MULTICAST_TTL,
	StandardSocketOptions.IP_MULTICAST_LOOP);
	}

	/**
	* Returns a set of SocketOptions supported by this impl
	* and by this impl's socket (DatagramSocket or MulticastSocket)
	*
	* @return a Set of SocketOptions
	*
	* @since 9
	*/
	protected Set<SocketOption<?>> supportedOptions() {
	if (getDatagramSocket() instanceof MulticastSocket) {
	return mcSocketOptions;
	} else {
	return dgSocketOptions;
	}
	}
	}

Back to index...