224  * be examined in order to determine the operations for which each channel is
225  * ready.  From each key one can retrieve the corresponding channel in order to
226  * perform whatever I/O operations are required.
227  *
228  * <p> That a selection key indicates that its channel is ready for some operation
229  * is a hint, but not a guarantee, that such an operation can be performed by a
230  * thread without causing the thread to block.  It is imperative that code that
231  * performs multiplexed I/O be written so as to ignore these hints when they prove
232  * to be incorrect.
233  *
234  * <p> This package defines selectable-channel classes corresponding to the {@link
235  * java.net.DatagramSocket}, {@link java.net.ServerSocket}, and {@link
236  * java.net.Socket} classes defined in the {@link java.net} package.
237  * Minor changes to these classes have been made in order to support sockets that
238  * are associated with channels.  This package also defines a simple class that
239  * implements unidirectional pipes.  In all cases, a new selectable channel is
240  * created by invoking the static {@code open} method of the corresponding class.
241  * If a channel needs an associated socket then a socket will be created as a side
242  * effect of this operation.
243  *






















244  * <p> The implementation of selectors, selectable channels, and selection keys
245  * can be replaced by "plugging in" an alternative definition or instance of the
246  * {@link java.nio.channels.spi.SelectorProvider} class defined in the {@link
247  * java.nio.channels.spi} package.  It is not expected that many developers
248  * will actually make use of this facility; it is provided primarily so that
249  * sophisticated users can take advantage of operating-system-specific
250  * I/O-multiplexing mechanisms when very high performance is required.
251  *
252  * <p> Much of the bookkeeping and synchronization required to implement the
253  * multiplexed-I/O abstractions is performed by the {@link
254  * java.nio.channels.spi.AbstractInterruptibleChannel}, {@link
255  * java.nio.channels.spi.AbstractSelectableChannel}, {@link
256  * java.nio.channels.spi.AbstractSelectionKey}, and {@link
257  * java.nio.channels.spi.AbstractSelector} classes in the {@link
258  * java.nio.channels.spi} package.  When defining a custom selector provider,
259  * only the {@link java.nio.channels.spi.AbstractSelector} and {@link
260  * java.nio.channels.spi.AbstractSelectionKey} classes should be subclassed
261  * directly; custom channel classes should extend the appropriate {@link
262  * java.nio.channels.SelectableChannel} subclasses defined in this package.
263  *

224  * be examined in order to determine the operations for which each channel is
225  * ready.  From each key one can retrieve the corresponding channel in order to
226  * perform whatever I/O operations are required.
227  *
228  * <p> That a selection key indicates that its channel is ready for some operation
229  * is a hint, but not a guarantee, that such an operation can be performed by a
230  * thread without causing the thread to block.  It is imperative that code that
231  * performs multiplexed I/O be written so as to ignore these hints when they prove
232  * to be incorrect.
233  *
234  * <p> This package defines selectable-channel classes corresponding to the {@link
235  * java.net.DatagramSocket}, {@link java.net.ServerSocket}, and {@link
236  * java.net.Socket} classes defined in the {@link java.net} package.
237  * Minor changes to these classes have been made in order to support sockets that
238  * are associated with channels.  This package also defines a simple class that
239  * implements unidirectional pipes.  In all cases, a new selectable channel is
240  * created by invoking the static {@code open} method of the corresponding class.
241  * If a channel needs an associated socket then a socket will be created as a side
242  * effect of this operation.
243  *
244  * <p> {@link java.nio.channels.DatagramChannel},
245  * {@link java.nio.channels.SocketChannel} and
246  * {@link java.nio.channels.ServerSocketChannel}s can be created
247  * with different {@link java.net.ProtocolFamily protocol families}. The standard
248  * family types are specified in {@link java.net.StandardProtocolFamily}.
249  *
250  * <p> Channels for <i>Internet Protocol</i> sockets are created using the
251  * {@link java.net.StandardProtocolFamily#INET INET} or {@link
252  * java.net.StandardProtocolFamily#INET6 INET6} protocol families. <i>Internet
253  * Protocol</i> sockets support network communication using TCP and UDP and are
254  * addressed using {@link java.net.InetSocketAddress}es which encapsulate an IP
255  * address and port number. <i>Internet Protocol</i> sockets are also the default
256  * type created, when a protocol family is not specified in the channel factory
257  * creation method.
258  *
259  * <p> Channels for <a id="unixdomain"></a><i>Unix Domain</i> sockets are created
260  * using the {@link java.net.StandardProtocolFamily#UNIX UNIX} protocol family.
261  * <i>Unix Domain</i> sockets support local inter-process
262  * communication on the same host, and are addressed using {@link
263  * java.net.UnixDomainSocketAddress}es which encapsulate a filesystem pathname
264  * on the local system.
265  *
266  * <p> The implementation of selectors, selectable channels, and selection keys
267  * can be replaced by "plugging in" an alternative definition or instance of the
268  * {@link java.nio.channels.spi.SelectorProvider} class defined in the {@link
269  * java.nio.channels.spi} package.  It is not expected that many developers
270  * will actually make use of this facility; it is provided primarily so that
271  * sophisticated users can take advantage of operating-system-specific
272  * I/O-multiplexing mechanisms when very high performance is required.
273  *
274  * <p> Much of the bookkeeping and synchronization required to implement the
275  * multiplexed-I/O abstractions is performed by the {@link
276  * java.nio.channels.spi.AbstractInterruptibleChannel}, {@link
277  * java.nio.channels.spi.AbstractSelectableChannel}, {@link
278  * java.nio.channels.spi.AbstractSelectionKey}, and {@link
279  * java.nio.channels.spi.AbstractSelector} classes in the {@link
280  * java.nio.channels.spi} package.  When defining a custom selector provider,
281  * only the {@link java.nio.channels.spi.AbstractSelector} and {@link
282  * java.nio.channels.spi.AbstractSelectionKey} classes should be subclassed
283  * directly; custom channel classes should extend the appropriate {@link
284  * java.nio.channels.SelectableChannel} subclasses defined in this package.
285  *