Pipe定义

Channel接口定义：http://donald-draper.iteye.com/blog/2369111
AbstractInterruptibleChannel接口定义：http://donald-draper.iteye.com/blog/2369238
SelectableChannel接口定义:http://donald-draper.iteye.com/blog/2369317
SelectionKey定义：http://donald-draper.iteye.com/blog/2369499
SelectorProvider定义：http://donald-draper.iteye.com/blog/2369615
AbstractSelectableChannel定义：http://donald-draper.iteye.com/blog/2369742
NetworkChannel接口定义：http://donald-draper.iteye.com/blog/2369773
Selector定义：http://donald-draper.iteye.com/blog/2370015
AbstractSelector定义：http://donald-draper.iteye.com/blog/2370138
SelectorImpl分析 :http://donald-draper.iteye.com/blog/2370519
WindowsSelectorImpl解析一（FdMap，PollArrayWrapper）：
http://donald-draper.iteye.com/blog/2370811
WindowsSelectorImpl解析二（选择操作，通道注册，通道反注册，选择器关闭等）：
http://donald-draper.iteye.com/blog/2370862
ByteChannel，分散聚集通道接口的定义（SocketChannel）:
http://donald-draper.iteye.com/blog/2371065
NIO-Pipe示例：http://donald-draper.iteye.com/blog/2373535
前面一篇文章我们看了一个管道实例，今天来看一下管道的定义

package java.nio.channels;
import java.io.IOException;
import java.nio.channels.spi.*;


/**
 * A pair of channels that implements a unidirectional pipe.
 *Pipe是一对单向通道的实现
 *  A pipe consists of a pair of channels: A writable {@link
 * Pipe.SinkChannel </code>sink<code>} channel and a readable {@link
 * Pipe.SourceChannel </code>source<code>} channel.  Once some bytes are
 * written to the sink channel they can be read from source channel in exactly
 * the order in which they were written.
 *管道Pipe包括一对通道，一个可写的SinkChannel，一个可读的SourceChannel。只要有字节序列
 写到sink通道，那么source通道可以按字节写的顺序读取字节序列。
 *  Whether or not a thread writing bytes to a pipe will block until another
 * thread reads those bytes, or some previously-written bytes, from the pipe is
 * system-dependent and therefore unspecified.  Many pipe implementations will
 * buffer up to a certain number of bytes between the sink and source channels,
 * but such buffering should not be assumed.  

 *一个线程是否可以写字节序列到管道，取决于是否有其他线程从依赖于系统的管道，
 读取这些字节序列或先前已写到管道的字节序列，因此是不确定的。许多管道的实现将会
 把一定数量的字节序列在sink与source通道之前缓存起来，但这种缓存不应该assumed。
 *
 * @author Mark Reinhold
 * @author JSR-51 Expert Group
 * @since 1.4
 */

public abstract class Pipe {

    /**
     * A channel representing the readable end of a {@link Pipe}.  
     *SourceChannel表示管道的可读端
     * @since 1.4
     */
    public static abstract class SourceChannel
        extends AbstractSelectableChannel
        implements ReadableByteChannel, ScatteringByteChannel
    {
        /**
         * Constructs a new instance of this class.
         */
        protected SourceChannel(SelectorProvider provider) {
            super(provider);
        }

        /**
         * Returns an operation set identifying this channel's supported
         * operations.
         *返回通道支持的操作事件
         *  Pipe-source channels only support reading, so this method
         * returns {@link SelectionKey#OP_READ}.  

         *由于管道的Source通道只支持读操作，所以此方只返回SelectionKey#OP_READ
         * @return  The valid-operation set
         */
        public final int validOps() {
            return SelectionKey.OP_READ;
        }

    }

    /**
     * A channel representing the writable end of a {@link Pipe}.  </p>
     * SinkChannel表示管道的可写端
     * @since 1.4
     */
    public static abstract class SinkChannel
        extends AbstractSelectableChannel
        implements WritableByteChannel, GatheringByteChannel
    {
        /**
         * Initializes a new instance of this class.
         */
        protected SinkChannel(SelectorProvider provider) {
            super(provider);
        }

        /**
         * Returns an operation set identifying this channel's supported
         * operations.
         *返回通道支持的操作事件
         *  Pipe-sink channels only support writing, so this method returns
         * {@link SelectionKey#OP_WRITE}.  

         *由于管道的Sink通道只支持写操作，所以此方只返回SelectionKey#OP_WRITE
         * @return  The valid-operation set
         */
        public final int validOps() {
            return SelectionKey.OP_WRITE;
        }

    }

    /**
     * Initializes a new instance of this class.
     */
    protected Pipe() { }

    /**
     * Returns this pipe's source channel.  </p>
     *获取管道的source通道
     * @return  This pipe's source channel
     */
    public abstract SourceChannel source();

    /**
     * Returns this pipe's sink channel.  </p>
     *获取管道的sink通道
     * @return  This pipe's sink channel
     */
    public abstract SinkChannel sink();

    /**
     * Opens a pipe.
     *打开一个管道
     *  The new pipe is created by invoking the {@link
     * java.nio.channels.spi.SelectorProvider#openPipe openPipe} method of the
     * system-wide default {@link java.nio.channels.spi.SelectorProvider}
     * object.  

     *
     * @return  A new pipe
     *
     * @throws  IOException
     *          If an I/O error occurs
     */
    public static Pipe open() throws IOException {
        return SelectorProvider.provider().openPipe();
    }
}

总结：
Pipe中包含一个可写通道SinkChannel和一个可读通道SourceChannel。sink向管道写字节序序列，source从管道读取字节序列。
PipeImpl解析：http://donald-draper.iteye.com/blog/2373628