org.jboss.netty.handler.queue

类 BlockingReadHandler<E>

java.lang.Object

org.jboss.netty.channel.SimpleChannelUpstreamHandler

org.jboss.netty.handler.queue.BlockingReadHandler<E>

类型参数:

E - the type of the received messages

所有已实现的接口:

ChannelHandler, ChannelUpstreamHandler

public class BlockingReadHandler<E>
extends SimpleChannelUpstreamHandler

Emulates blocking read operation. This handler stores all received messages into a BlockingQueue and returns the received messages when read(), read(long, TimeUnit), readEvent(), or readEvent(long, TimeUnit) method is called.

Please note that this handler is only useful for the cases where there are very small number of connections, such as testing and simple client-side application development.

Also, any handler placed after this handler will never receive messageReceived, exceptionCaught, and channelClosed events, hence it should be placed in the last place in a pipeline.

Here is an example that demonstrates the usage:

 BlockingReadHandler<ChannelBuffer> reader =
         new BlockingReadHandler<ChannelBuffer>();
 ChannelPipeline p = ...;
 p.addLast("reader", reader);

 ...

 // Read a message from a channel in a blocking manner.
 try {
     ChannelBuffer buf = reader.read(60, TimeUnit.SECONDS);
     if (buf == null) {
         // Connection closed.
     } else {
         // Handle the received message here.
     }
 } catch (BlockingReadTimeoutException e) {
     // Read timed out.
 } catch (IOException e) {
     // Other read errors
 }
 

嵌套类概要

从接口继承的嵌套类/接口 org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

构造器概要

构造器

构造器和说明
BlockingReadHandler() Creates a new instance with LinkedBlockingQueue
BlockingReadHandler(java.util.concurrent.BlockingQueue<ChannelEvent> queue) Creates a new instance with the specified BlockingQueue.

方法概要

方法

限定符和类型	方法和说明
void	channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) Invoked when a Channel was closed and all its related resources were released.
void	exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) Invoked when an exception was raised by an I/O thread or a ChannelHandler.
protected java.util.concurrent.BlockingQueue<ChannelEvent>	getQueue() Returns the queue which stores the received messages.
boolean	isClosed() Returns true if and only if the Channel associated with this handler has been closed.
void	messageReceived(ChannelHandlerContext ctx, MessageEvent e) Invoked when a message object (e.g: ChannelBuffer) was received from a remote peer.
E	read() Waits until a new message is received or the associated Channel is closed.
E	read(long timeout, java.util.concurrent.TimeUnit unit) Waits until a new message is received or the associated Channel is closed.
ChannelEvent	readEvent() Waits until a new ChannelEvent is received or the associated Channel is closed.
ChannelEvent	readEvent(long timeout, java.util.concurrent.TimeUnit unit) Waits until a new ChannelEvent is received or the associated Channel is closed.

从类继承的方法 org.jboss.netty.channel.SimpleChannelUpstreamHandler

channelBound, channelConnected, channelDisconnected, channelInterestChanged, channelOpen, channelUnbound, childChannelClosed, childChannelOpen, handleUpstream, writeComplete

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

BlockingReadHandler

public BlockingReadHandler()

Creates a new instance with LinkedBlockingQueue

BlockingReadHandler

public BlockingReadHandler(java.util.concurrent.BlockingQueue<ChannelEvent> queue)

Creates a new instance with the specified BlockingQueue.

方法详细资料

getQueue

protected java.util.concurrent.BlockingQueue<ChannelEvent> getQueue()

Returns the queue which stores the received messages. The default implementation returns the queue which was specified in the constructor.

isClosed

public boolean isClosed()

Returns true if and only if the Channel associated with this handler has been closed.

抛出:

java.lang.IllegalStateException - if this handler was not added to a ChannelPipeline yet

read

public E read()
       throws java.io.IOException,
              java.lang.InterruptedException

Waits until a new message is received or the associated Channel is closed.

返回:

the received message or null if the associated Channel has been closed

抛出:

java.io.IOException - if failed to receive a new message

java.lang.InterruptedException - if the operation has been interrupted

read

public E read(long timeout,
     java.util.concurrent.TimeUnit unit)
       throws java.io.IOException,
              java.lang.InterruptedException

Waits until a new message is received or the associated Channel is closed.

参数:

timeout - the amount time to wait until a new message is received. If no message is received within the timeout, BlockingReadTimeoutException is thrown.

unit - the unit of timeout

返回:

the received message or null if the associated Channel has been closed

抛出:

BlockingReadTimeoutException - if no message was received within the specified timeout

java.io.IOException - if failed to receive a new message

java.lang.InterruptedException - if the operation has been interrupted

readEvent

public ChannelEvent readEvent()
                       throws java.lang.InterruptedException

Waits until a new ChannelEvent is received or the associated Channel is closed.

返回:

a MessageEvent or an ExceptionEvent. null if the associated Channel has been closed

抛出:

java.lang.InterruptedException - if the operation has been interrupted

readEvent

public ChannelEvent readEvent(long timeout,
                     java.util.concurrent.TimeUnit unit)
                       throws java.lang.InterruptedException,
                              BlockingReadTimeoutException

Waits until a new ChannelEvent is received or the associated Channel is closed.

参数:

timeout - the amount time to wait until a new ChannelEvent is received. If no message is received within the timeout, BlockingReadTimeoutException is thrown.

unit - the unit of timeout

返回:

a MessageEvent or an ExceptionEvent. null if the associated Channel has been closed

抛出:

BlockingReadTimeoutException - if no event was received within the specified timeout

java.lang.InterruptedException - if the operation has been interrupted

messageReceived

public void messageReceived(ChannelHandlerContext ctx,
                   MessageEvent e)
                     throws java.lang.Exception

从类复制的说明: SimpleChannelUpstreamHandler

Invoked when a message object (e.g: ChannelBuffer) was received from a remote peer.

覆盖:

messageReceived 在类中 SimpleChannelUpstreamHandler

抛出:

java.lang.Exception

exceptionCaught

public void exceptionCaught(ChannelHandlerContext ctx,
                   ExceptionEvent e)
                     throws java.lang.Exception

从类复制的说明: SimpleChannelUpstreamHandler

Invoked when an exception was raised by an I/O thread or a ChannelHandler.

覆盖:

exceptionCaught 在类中 SimpleChannelUpstreamHandler

抛出:

java.lang.Exception

channelClosed

public void channelClosed(ChannelHandlerContext ctx,
                 ChannelStateEvent e)
                   throws java.lang.Exception

从类复制的说明: SimpleChannelUpstreamHandler

Invoked when a Channel was closed and all its related resources were released.

覆盖:

channelClosed 在类中 SimpleChannelUpstreamHandler

抛出:

java.lang.Exception