< prev index next >
src/java.base/share/classes/java/nio/channels/ServerSocketChannel.java
Print this page
@@ -24,31 +24,37 @@
*/
package java.nio.channels;
import java.io.IOException;
+import java.net.NetPermission;
import java.net.ProtocolFamily;
import java.net.ServerSocket;
import java.net.SocketOption;
import java.net.SocketAddress;
+import java.net.UnixDomainSocketAddress;
import java.nio.channels.spi.AbstractSelectableChannel;
import java.nio.channels.spi.SelectorProvider;
import static java.util.Objects.requireNonNull;
/**
* A selectable channel for stream-oriented listening sockets.
*
- * <p> A server-socket channel is created by invoking the {@link #open() open}
- * method of this class. It is not possible to create a channel for an arbitrary,
- * pre-existing {@link ServerSocket}. A newly-created server-socket channel is
- * open but not yet bound. An attempt to invoke the {@link #accept() accept}
- * method of an unbound server-socket channel will cause a {@link NotYetBoundException}
+ * <p> A server-socket channel is created by invoking one of the {@code open}
+ * methods of this class. The no-arg {@link #open() open} method opens a server-socket
+ * channel for an <i>Internet protocol</i> socket. The {@link #open(ProtocolFamily)}
+ * method is used to open a server-socket channel for a socket of a specified
+ * protocol family. It is not possible to create a channel for an arbitrary,
+ * pre-existing socket. A newly-created server-socket channel is open but not yet
+ * bound. An attempt to invoke the {@link #accept() accept} method of an
+ * unbound server-socket channel will cause a {@link NotYetBoundException}
* to be thrown. A server-socket channel can be bound by invoking one of the
- * {@link #bind(java.net.SocketAddress,int) bind} methods defined by this class.
+ * {@link #bind(java.net.SocketAddress, int) bind} methods defined by this class.
*
* <p> Socket options are configured using the {@link #setOption(SocketOption,Object)
- * setOption} method. Server-socket channels support the following options:
+ * setOption} method. Server-socket channels for <i>Internet protocol</i> sockets
+ * support the following options:
* <blockquote>
* <table class="striped">
* <caption style="display:none">Socket options</caption>
* <thead>
* <tr>
@@ -66,11 +72,31 @@
* <td> Re-use address </td>
* </tr>
* </tbody>
* </table>
* </blockquote>
- * Additional (implementation specific) options may also be supported.
+ *
+ * <p> Server-socket channels for <i>Unix domain</i> sockets support:
+ * <blockquote>
+ * <table class="striped">
+ * <caption style="display:none">Socket options</caption>
+ * <thead>
+ * <tr>
+ * <th scope="col">Option Name</th>
+ * <th scope="col">Description</th>
+ * </tr>
+ * </thead>
+ * <tbody>
+ * <tr>
+ * <th scope="row"> {@link java.net.StandardSocketOptions#SO_RCVBUF SO_RCVBUF} </th>
+ * <td> The size of the socket receive buffer </td>
+ * </tr>
+ * </tbody>
+ * </table>
+ * </blockquote>
+ *
+ * <p> Additional (implementation specific) options may also be supported.
*
* <p> Server-socket channels are safe for use by multiple concurrent threads.
* </p>
*
* @author Mark Reinhold
@@ -92,11 +118,11 @@
protected ServerSocketChannel(SelectorProvider provider) {
super(provider);
}
/**
- * Opens a server-socket channel.
+ * Opens a server-socket channel for an <i>Internet protocol</i> socket.
*
* <p> The new channel is created by invoking the {@link
* java.nio.channels.spi.SelectorProvider#openServerSocketChannel
* openServerSocketChannel} method of the system-wide default {@link
* java.nio.channels.spi.SelectorProvider} object.
@@ -108,17 +134,20 @@
*
* @return A new socket channel
*
* @throws IOException
* If an I/O error occurs
+ *
+ * @see <a href="../../net/doc-files/net-properties.html#Ipv4IPv6">
+ * java.net.preferIPv4Stack</a> system property
*/
public static ServerSocketChannel open() throws IOException {
return SelectorProvider.provider().openServerSocketChannel();
}
/**
- * Opens a server-socket channel.The {@code family} parameter specifies the
+ * Opens a server-socket channel. The {@code family} parameter specifies the
* {@link ProtocolFamily protocol family} of the channel's socket.
*
* <p> The new channel is created by invoking the {@link
* java.nio.channels.spi.SelectorProvider#openServerSocketChannel(ProtocolFamily)
* openServerSocketChannel(ProtocolFamily)} method of the system-wide default {@link
@@ -135,10 +164,13 @@
* java.net.StandardProtocolFamily#INET6 StandardProtocolFamily.INET6}
* but IPv6 is not enabled on the platform.
* @throws IOException
* If an I/O error occurs
*
+ * @see <a href="../../net/doc-files/net-properties.html#Ipv4IPv6">
+ * java.net.preferIPv4Stack</a> system property
+ *
* @since 15
*/
public static ServerSocketChannel open(ProtocolFamily family) throws IOException {
return SelectorProvider.provider().openServerSocketChannel(requireNonNull(family));
}
@@ -178,12 +210,11 @@
* @throws AlreadyBoundException {@inheritDoc}
* @throws UnsupportedAddressTypeException {@inheritDoc}
* @throws ClosedChannelException {@inheritDoc}
* @throws IOException {@inheritDoc}
* @throws SecurityException
- * If a security manager has been installed and its {@link
- * SecurityManager#checkListen checkListen} method denies the
+ * If a security manager has been installed and it denies the
* operation
*
* @since 1.7
*/
public final ServerSocketChannel bind(SocketAddress local)
@@ -195,23 +226,39 @@
/**
* Binds the channel's socket to a local address and configures the socket to
* listen for connections.
*
* <p> This method is used to establish an association between the socket and
- * a local address. Once an association is established then the socket remains
- * bound until the channel is closed.
+ * a local address. For <i>Internet protocol</i> sockets, once an association
+ * is established then the socket remains bound until the channel is closed.
*
* <p> The {@code backlog} parameter is the maximum number of pending
* connections on the socket. Its exact semantics are implementation specific.
* In particular, an implementation may impose a maximum length or may choose
* to ignore the parameter altogther. If the {@code backlog} parameter has
* the value {@code 0}, or a negative value, then an implementation specific
* default is used.
*
+ * @apiNote
+ * Binding a server socket channel for a <i>Unix Domain</i> socket, creates a
+ * file corresponding to the file path in the {@link UnixDomainSocketAddress}.
+ * This file persists after the channel is closed, and must be removed before
+ * another socket can bind to the same name. Binding to a {@code null} address
+ * causes the socket to be <i>automatically</i> bound to some unique file
+ * in a system temporary location. The associated socket file also persists
+ * after the channel is closed. Its name can be obtained from the channel's
+ * local socket address.
+ *
+ * @implNote
+ * Each platform enforces an implementation specific, maximum length for the
+ * name of a <i>Unix Domain</i> socket. This limitation is enforced when a
+ * channel is bound. The maximum length is typically close to and generally
+ * not less than 100 bytes.
+ *
* @param local
- * The address to bind the socket, or {@code null} to bind to an
- * automatically assigned socket address
+ * The address to bind the socket, or {@code null} to bind to
+ * an automatically assigned socket address
* @param backlog
* The maximum number of pending connections
*
* @return This channel
*
@@ -223,12 +270,14 @@
* If this channel is closed
* @throws IOException
* If some other I/O error occurs
* @throws SecurityException
* If a security manager has been installed and its {@link
- * SecurityManager#checkListen checkListen} method denies the
- * operation
+ * SecurityManager#checkListen checkListen} method denies
+ * the operation for an <i>Internet protocol</i> socket address,
+ * or for a <i>Unix domain</i> socket address if it denies
+ * {@link NetPermission}{@code("accessUnixDomainSocket")}.
*
* @since 1.7
*/
public abstract ServerSocketChannel bind(SocketAddress local, int backlog)
throws IOException;
@@ -249,10 +298,13 @@
*
* <p> The returned object will not declare any public methods that are not
* declared in the {@link java.net.ServerSocket} class. </p>
*
* @return A server socket associated with this channel
+ *
+ * @throws UnsupportedOperationException
+ * If the channel's socket is not an <i>Internet protocol</i> socket
*/
public abstract ServerSocket socket();
/**
* Accepts a connection made to this channel's socket.
@@ -263,17 +315,19 @@
* or an I/O error occurs.
*
* <p> The socket channel returned by this method, if any, will be in
* blocking mode regardless of the blocking mode of this channel.
*
- * <p> This method performs exactly the same security checks as the {@link
- * java.net.ServerSocket#accept accept} method of the {@link
- * java.net.ServerSocket} class. That is, if a security manager has been
- * installed then for each new connection this method verifies that the
- * address and port number of the connection's remote endpoint are
- * permitted by the security manager's {@link
- * java.lang.SecurityManager#checkAccept checkAccept} method. </p>
+ * <p> If bound to an <i>Internet protocol</i> socket address, this method
+ * performs exactly the same security checks as the {@link
+ * java.net.ServerSocket#accept accept} method of the {@link java.net.ServerSocket}
+ * class. That is, if a security manager has been installed then for each
+ * new connection this method verifies that the address and port number
+ * of the connection's remote endpoint are permitted by the security
+ * manager's {@link java.lang.SecurityManager#checkAccept checkAccept}
+ * method. If bound to a <i>Unix Domain</i> socket address, this method checks
+ * {@link NetPermission}{@code ("accessUnixDomainSocket")}.
*
* @return The socket channel for the new connection,
* or {@code null} if this channel is in non-blocking mode
* and no connection is available to be accepted
*
@@ -303,25 +357,31 @@
*/
public abstract SocketChannel accept() throws IOException;
/**
* {@inheritDoc}
- * <p>
+ *
* If there is a security manager set, its {@code checkConnect} method is
* called with the local address and {@code -1} as its arguments to see
* if the operation is allowed. If the operation is not allowed,
* a {@code SocketAddress} representing the
* {@link java.net.InetAddress#getLoopbackAddress loopback} address and the
* local port of the channel's socket is returned.
*
+ * <p> Where the channel is bound to a <i>Unix Domain</i> socket address, the socket
+ * address is a {@link UnixDomainSocketAddress}. If there is a security manager
+ * set, its {@link SecurityManager#checkPermission(java.security.Permission)
+ * checkPermission} method is called with {@link NetPermission}{@code
+ * ("accessUnixDomainSocket")}. If the operation is not allowed an unnamed
+ * {@link UnixDomainSocketAddress} is returned.
+ *
* @return The {@code SocketAddress} that the socket is bound to, or the
- * {@code SocketAddress} representing the loopback address if
- * denied by the security manager, or {@code null} if the
+ * {@code SocketAddress} representing the loopback address or empty
+ * path if denied by the security manager, or {@code null} if the
* channel's socket is not bound
*
* @throws ClosedChannelException {@inheritDoc}
* @throws IOException {@inheritDoc}
*/
@Override
public abstract SocketAddress getLocalAddress() throws IOException;
-
}
< prev index next >