public class ClientBootstrap extends Bootstrap
Channel
and makes a
connection attempt.
Options
are used to configure a channel:
For the detailed list of available options, please refer toClientBootstrap
b = ...; // Options for a new channel b.setOption("remoteAddress", newInetSocketAddress
("example.com", 8080)); b.setOption("tcpNoDelay", true); b.setOption("receiveBufferSize", 1048576);
ChannelConfig
and its sub-types.
ChannelPipeline
and you can configure it
in two ways.
The recommended approach is to specify a ChannelPipelineFactory
by
calling Bootstrap.setPipelineFactory(ChannelPipelineFactory)
.
ClientBootstrap
b = ...; b.setPipelineFactory(new MyPipelineFactory()); public class MyPipelineFactory implementsChannelPipelineFactory
{ publicChannelPipeline
getPipeline() throws Exception { // Create and configure a new pipeline for a new channel.ChannelPipeline
p =Channels
.pipeline(); p.addLast("encoder", new EncodingHandler()); p.addLast("decoder", new DecodingHandler()); p.addLast("logic", new LogicHandler()); return p; } }
The alternative approach, which works only in a certain situation, is to use the default pipeline and let the bootstrap to shallow-copy the default pipeline for each new channel:
Please note 'shallow-copy' here means that the addedClientBootstrap
b = ...;ChannelPipeline
p = b.getPipeline(); // Add handlers to the default pipeline. p.addLast("encoder", new EncodingHandler()); p.addLast("decoder", new DecodingHandler()); p.addLast("logic", new LogicHandler());
ChannelHandler
s
are not cloned but only their references are added to the new pipeline.
Therefore, you cannot use this approach if you are going to open more than
one Channel
s or run a server that accepts incoming connections to
create its child channels.
Channel
sClientBootstrap
is just a helper class. It neither allocates nor
manages any resources. What manages the resources is the
ChannelFactory
implementation you specified in the constructor of
ClientBootstrap
. Therefore, it is OK to create as many
ClientBootstrap
instances as you want with the same
ChannelFactory
to apply different settings for different
Channel
s.Constructor and Description |
---|
ClientBootstrap()
Creates a new instance with no
ChannelFactory set. |
ClientBootstrap(ChannelFactory channelFactory)
Creates a new instance with the specified initial
ChannelFactory . |
Modifier and Type | Method and Description |
---|---|
ChannelFuture |
bind(SocketAddress localAddress)
Attempts to bind a channel with the specified
localAddress . later the channel can
be connected to a remoteAddress by calling Channel.connect(SocketAddress) .This method
is useful where bind and connect need to be done in separate steps. |
ChannelFuture |
connect()
Attempts a new connection with the current
"remoteAddress" and
"localAddress" option. |
ChannelFuture |
connect(SocketAddress remoteAddress)
Attempts a new connection with the specified
remoteAddress and
the current "localAddress" option. |
ChannelFuture |
connect(SocketAddress remoteAddress,
SocketAddress localAddress)
Attempts a new connection with the specified
remoteAddress and
the specified localAddress . |
getFactory, getOption, getOptions, getPipeline, getPipelineAsMap, getPipelineFactory, releaseExternalResources, setFactory, setOption, setOptions, setPipeline, setPipelineAsMap, setPipelineFactory, shutdown
public ClientBootstrap()
ChannelFactory
set.
Bootstrap.setFactory(ChannelFactory)
must be called before any I/O
operation is requested.public ClientBootstrap(ChannelFactory channelFactory)
ChannelFactory
.public ChannelFuture connect()
"remoteAddress"
and
"localAddress"
option. If the "localAddress"
option is
not set, the local address of a new channel is determined automatically.
This method is similar to the following code:
ClientBootstrap
b = ...;
b.connect(b.getOption("remoteAddress"), b.getOption("localAddress"));
IllegalStateException
- if "remoteAddress"
option was not setClassCastException
- if "remoteAddress"
or "localAddress"
option's
value is neither a SocketAddress
nor null
ChannelPipelineException
- if this bootstrap's pipelineFactory
failed to create a new ChannelPipeline
public ChannelFuture connect(SocketAddress remoteAddress)
remoteAddress
and
the current "localAddress"
option. If the "localAddress"
option is not set, the local address of a new channel is determined
automatically. This method is identical with the following code:
ClientBootstrap
b = ...;
b.connect(remoteAddress, b.getOption("localAddress"));
ClassCastException
- if "localAddress"
option's value is
neither a SocketAddress
nor null
ChannelPipelineException
- if this bootstrap's pipelineFactory
failed to create a new ChannelPipeline
public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress)
remoteAddress
and
the specified localAddress
. If the specified local address is
null
, the local address of a new channel is determined
automatically.ChannelPipelineException
- if this bootstrap's pipelineFactory
failed to create a new ChannelPipeline
public ChannelFuture bind(SocketAddress localAddress)
localAddress
. later the channel can
be connected to a remoteAddress by calling Channel.connect(SocketAddress)
.This method
is useful where bind and connect need to be done in separate steps.
For an instance, a user can set an attachment to the Channel
via
Channel.setAttachment(Object)
before beginning a connection attempt so that the user can access
the attachment once the connection is established:
ChannelFuture bindFuture = bootstrap.bind(new InetSocketAddress("192.168.0.15", 0)); Channel channel = bindFuture.getChannel(); channel.setAttachment(dataObj); channel.connect(new InetSocketAddress("192.168.0.30", 8080));The attachment can be accessed then in the handler like the following:
public class YourHandler extends SimpleChannelUpstreamHandler { public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception { Object dataObject = ctx.getChannel().getAttachment(); } }
ChannelPipelineException
- if this bootstrap's pipelineFactory
failed to create a new ChannelPipeline
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