com.fr.third.jgroups.fork

类 ForkChannel

java.lang.Object

com.fr.third.jgroups.Channel

com.fr.third.jgroups.JChannel

com.fr.third.jgroups.fork.ForkChannel

所有已实现的接口:

ChannelListener, java.io.Closeable, java.lang.AutoCloseable

public class ForkChannel
extends JChannel
implements ChannelListener

Implementation of a ForkChannel, which is a light-weight channel. Not all methods are supported, UnsupportedOperationExceptions will be thrown if an unsupported operation is called. See doc/design/FORK.txt for details

从以下版本开始:

3.4

作者:

Bela Ban

嵌套类概要

从类继承的嵌套类/接口 com.fr.third.jgroups.Channel

Channel.State

字段概要

字段

限定符和类型	字段和说明
protected static java.lang.reflect.Field[]	copied_fields
protected java.lang.String	fork_channel_id
protected Channel	main_channel

从类继承的字段 com.fr.third.jgroups.JChannel

address_generators, cluster_name, config, DEFAULT_PROTOCOL_STACK, flush_supported, local_addr, my_view, name, probe_handler, prot_stack, received_bytes, received_msgs, sent_bytes, sent_msgs, state_promise, state_transfer_supported, stats

从类继承的字段 com.fr.third.jgroups.Channel

channel_listeners, discard_own_messages, log, receiver, socket_factory, state, up_handler

构造器概要

构造器

构造器和说明
ForkChannel(Channel main_channel, java.lang.String fork_stack_id, java.lang.String fork_channel_id, boolean create_fork_if_absent, int position, java.lang.Class<? extends Protocol> neighbor, Protocol... protocols) Creates a new fork-channel from a main-channel.
ForkChannel(Channel main_channel, java.lang.String fork_stack_id, java.lang.String fork_channel_id, Protocol... protocols) Creates a new fork-channel from a main-channel.

方法概要

方法

限定符和类型	方法和说明
void	addAddressGenerator(AddressGenerator address_generator) Sets the new AddressGenerator.
void	channelClosed(Channel channel) Channel has been closed notification callback
void	channelConnected(Channel channel) Channel has been connected notification callback
void	channelDisconnected(Channel channel) Channel has been disconnected notification callback
void	close() Closes the fork-channel, essentially setting its state to CLOSED.
void	connect(java.lang.String cluster_name) Connects the fork-channel, which will be operational after this.
void	connect(java.lang.String cluster_name, Address target, long timeout) Connects this channel to a group and gets a state from a specified state provider.
protected void	copyFields() Copies state from main-channel to this fork-channel
void	disconnect() Removes the fork-channel from the fork-stack's hashmap and resets its state.
java.lang.Object	down(Event evt) Sends an event down the protocol stack.
protected static FORK	getFORK(Channel ch, int position, java.lang.Class<? extends Protocol> neighbor, boolean create_fork_if_absent)
protected static ForkProtocolStack	getForkStack(Protocol prot)
void	getState(Address target, long timeout) Retrieves the full state from the target member.
JChannel	name(java.lang.String name) Names a channel, same as Channel.setName(String)
protected void	nullFields()
void	send(Message msg) Sends a message.
protected void	setHeader(Message msg)
protected void	setLocalAddress(Address local_addr)
void	setName(java.lang.String name) Sets the logical name for the channel.
void	startFlush(boolean automatic_resume) Performs the flush of the cluster, ie. all pending application messages are flushed out of the cluster and all members ack their reception.
void	startFlush(java.util.List<Address> flushParticipants, boolean automatic_resume) Performs the flush of the cluster but only for the specified flush participants.
void	stopFlush() Stops the current flush of the cluster.
void	stopFlush(java.util.List<Address> flushParticipants) Stops the current flush of the cluster for the specified flush participants.

从类继承的方法 com.fr.third.jgroups.JChannel

_close, _connect, _preConnect, checkClosed, checkClosedOrNotConnected, connect, connect, dumpChannelStats, dumpStats, dumpStats, dumpStats, dumpTimerQueue, enableStats, flushSupported, generateAddress, getAddress, getAddressAsString, getAddressAsUUID, getAddressGenerator, getClusterName, getName, getName, getNumberOfTasksInTimer, getProperties, getProtocolStack, getReceivedBytes, getReceivedMessages, getSentBytes, getSentMessages, getState, getState, getTimer, getTimerThreads, getVersion, getView, getViewAsString, init, init, init, invokeCallback, printProtocolSpec, receiver, removeAddressGenerator, resetStats, send, send, send, setAddress, setAddressGenerator, setProtocolStack, startStack, statsEnabled, stopStack, toString, up, up

从类继承的方法 com.fr.third.jgroups.Channel

addChannelListener, clearChannelListeners, getDiscardOwnMessages, getReceiver, getSocketFactory, getState, getUpHandler, isClosed, isConnected, isConnecting, isOpen, notifyChannelClosed, notifyChannelConnected, notifyChannelDisconnected, removeChannelListener, setDiscardOwnMessages, setReceiver, setSocketFactory, setUpHandler

从类继承的方法 java.lang.Object

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

字段详细资料

main_channel

protected final Channel main_channel

fork_channel_id

protected final java.lang.String fork_channel_id

copied_fields

protected static final java.lang.reflect.Field[] copied_fields

构造器详细资料

ForkChannel

public ForkChannel(Channel main_channel,
           java.lang.String fork_stack_id,
           java.lang.String fork_channel_id,
           boolean create_fork_if_absent,
           int position,
           java.lang.Class<? extends Protocol> neighbor,
           Protocol... protocols)
            throws java.lang.Exception

Creates a new fork-channel from a main-channel. The channel is unconnected and connect(String) needs to be called to send and receive messages.

参数:

main_channel - The main-channel. The lifetime of the newly created channel will be less than or equal to the main-channel

fork_stack_id - The ID to associate the fork-stack with in FORK

fork_channel_id - The ID used to map fork-channel IDs to ForkChannels in the fork-channels protocol stack

create_fork_if_absent - If true, and FORK doesn't exist, a new FORK protocol will be created and inserted into the main-stack at the given position. If false, and FORK doesn't exist, an exception will be thrown

position - The position at which the newly created FORK will be inserted. ProtocolStack.ABOVE or ProtocolStack.BELOW are accepted. Ignored if create_fork_if_absent is false.

neighbor - The class of the neighbor protocol below or above which the newly created FORK protocol will be inserted. Ignored if create_fork_if_absent is false.

protocols - A list of protocols (from bottom to top !) to insert as the fork_stack in FORK under the given fork_stack_id. If the fork-stack with fork_stack_id already exists, an exception will be thrown. Can be null if no protocols should be added. This may be the case when an app only wants to use a ForkChannel to mux/demux messages, but doesn't need a different protocol stack.

抛出:

java.lang.Exception

ForkChannel

public ForkChannel(Channel main_channel,
           java.lang.String fork_stack_id,
           java.lang.String fork_channel_id,
           Protocol... protocols)
            throws java.lang.Exception

Creates a new fork-channel from a main-channel. The channel is unconnected and connect(String) needs to be called to send and receive messages. If FORK is not found in the stack, an exception will be thrown.

参数:

main_channel - The main-channel. The lifetime of the newly created channel will be less than or equal to the main-channel

fork_stack_id - The ID to associate the fork-stack with in FORK

fork_channel_id - The ID used to map fork-channel IDs to ForkChannels in the fork-channels protocol stack

protocols - A list of protocols (from bottom to top !) to insert as the fork_stack in FORK under the given fork_stack_id. If the fork-stack with fork_stack_id already exists, an exception will be thrown. Can be null if no protocols should be added. This may be the case when an app only wants to use a ForkChannel to mux/demux messages, but doesn't need a different protocol stack.

抛出:

java.lang.Exception

方法详细资料

setName

public void setName(java.lang.String name)

从类复制的说明: Channel

Sets the logical name for the channel. The name will stay associated with this channel for the channel's lifetime (until close() is called). This method should be called before calling connect().

覆盖:

setName 在类中 JChannel

name

public JChannel name(java.lang.String name)

从类复制的说明: Channel

Names a channel, same as Channel.setName(String)

覆盖:

name 在类中 JChannel

channelConnected

public void channelConnected(Channel channel)

从接口复制的说明: ChannelListener

Channel has been connected notification callback

指定者:

channelConnected 在接口中 ChannelListener

参数:

channel - the channel that has been connected

channelDisconnected

public void channelDisconnected(Channel channel)

从接口复制的说明: ChannelListener

Channel has been disconnected notification callback

指定者:

channelDisconnected 在接口中 ChannelListener

参数:

channel - the disconnected channel

channelClosed

public void channelClosed(Channel channel)

从接口复制的说明: ChannelListener

Channel has been closed notification callback

指定者:

channelClosed 在接口中 ChannelListener

参数:

channel - the closed channel

connect

public void connect(java.lang.String cluster_name)
             throws java.lang.Exception

Connects the fork-channel, which will be operational after this. Note that the fork-channel will have the same state as the main-channel, ie. if the main-channel is disconnected, so will the fork-channel be, even if connect() was called. This connect() method essentially adds the fork-channel to the fork-stack's hashmap, ready to send/receive messages as soon as the main-channel has been connected.

This method does not affect the main-channel.

覆盖:

connect 在类中 JChannel

参数:

cluster_name - Ignored, will be the same as the main-channel's cluster name

抛出:

java.lang.Exception

java.lang.IllegalStateException - The channel is closed

connect

public void connect(java.lang.String cluster_name,
           Address target,
           long timeout)
             throws java.lang.Exception

从类复制的说明: Channel

Connects this channel to a group and gets a state from a specified state provider.

This method essentially invokes connect and getState methods successively. If FLUSH protocol is in channel's stack definition only one flush is executed for both connecting and fetching state rather than two flushes if we invoke connect and getState in succession.

If the channel is closed an exception will be thrown.

覆盖:

connect 在类中 JChannel

参数:

cluster_name - the cluster name to connect to. Cannot be null.

target - the state provider. If null state will be fetched from coordinator, unless this channel is coordinator.

timeout - the timeout for state transfer.

抛出:

java.lang.Exception - Connecting to the cluster or state transfer was not successful

java.lang.IllegalStateException - The channel is closed and therefore cannot be used

disconnect

public void disconnect()

Removes the fork-channel from the fork-stack's hashmap and resets its state. Does not affect the main-channel

覆盖:

disconnect 在类中 JChannel

另请参阅:

Channel.connect(String)

close

public void close()

Closes the fork-channel, essentially setting its state to CLOSED. Note that - contrary to a regular channel - a closed fork-channel can be connected again: this means re-attaching the fork-channel to the main-channel

指定者:

close 在接口中 java.io.Closeable

指定者:

close 在接口中 java.lang.AutoCloseable

覆盖:

close 在类中 JChannel

down

public java.lang.Object down(Event evt)

从类复制的说明: JChannel

Sends an event down the protocol stack. Note that - contrary to JChannel.send(Message), if the event is a message, no checks are performed whether the channel is closed or disconnected.

覆盖:

down 在类中 JChannel

参数:

evt - the message to send down, encapsulated in an event

返回:

a response from a particular protocol layer targeted by Event parameter

send

public void send(Message msg)
          throws java.lang.Exception

从类复制的说明: Channel

Sends a message. The message contains

1. a destination address (Address). A null address sends the message to all group members.
2. a source address. Can be left empty as it will be assigned automatically
3. a byte buffer. The message contents.
4. several additional fields. They can be used by application programs (or patterns). E.g. a message ID, flags etc

覆盖:

send 在类中 JChannel

参数:

msg - The message to be sent. Destination and buffer should be set. A null destination means to send to all group members.

抛出:

java.lang.IllegalStateException - thrown if the channel is disconnected or closed

java.lang.Exception

startFlush

public void startFlush(java.util.List<Address> flushParticipants,
              boolean automatic_resume)
                throws java.lang.Exception

从类复制的说明: Channel

Performs the flush of the cluster but only for the specified flush participants.

All pending messages are flushed out but only for the flush participants. The remaining members in the cluster are not included in the flush. The list of flush participants should be a proper subset of the current view.

If this flush is not automatically resumed it is an obligation of the application to invoke the matching Channel.stopFlush(List) method with the same list of members used in Channel.startFlush(List, boolean).

覆盖:

startFlush 在类中 JChannel

automatic_resume - if true call Channel.stopFlush() after the flush

抛出:

java.lang.Exception

另请参阅:

Channel.startFlush(boolean), Util.startFlush(Channel, List, int, long, long)

startFlush

public void startFlush(boolean automatic_resume)
                throws java.lang.Exception

从类复制的说明: Channel

Performs the flush of the cluster, ie. all pending application messages are flushed out of the cluster and all members ack their reception. After this call returns, no member will be allowed to send any messages until Channel.stopFlush() is called.

In the case of flush collisions (another member attempts flush at roughly the same time) start flush will fail by throwing an Exception. Applications can re-attempt flushing after certain back-off period.

JGroups provides a helper random sleep time backoff algorithm for flush using Util class.

覆盖:

startFlush 在类中 JChannel

参数:

automatic_resume - if true call Channel.stopFlush() after the flush

抛出:

java.lang.Exception

另请参阅:

Util.startFlush(Channel, List, int, long, long)

stopFlush

public void stopFlush()

从类复制的说明: Channel

Stops the current flush of the cluster. Cluster members are unblocked and allowed to send new and pending messages.

覆盖:

stopFlush 在类中 JChannel

另请参阅:

Channel.startFlush(boolean), Channel.startFlush(List, boolean)

stopFlush

public void stopFlush(java.util.List<Address> flushParticipants)

从类复制的说明: Channel

Stops the current flush of the cluster for the specified flush participants. Flush participants are unblocked and allowed to send new and pending messages.

It is an obligation of the application to invoke the matching Channel.startFlush(List, boolean) method with the same list of members prior to invocation of this method.

覆盖:

stopFlush 在类中 JChannel

参数:

flushParticipants - the flush participants

getState

public void getState(Address target,
            long timeout)
              throws java.lang.Exception

从类复制的说明: Channel

Retrieves the full state from the target member.

State transfer is initiated by invoking getState on this channel. The state provider in turn invokes MessageListener.getState(java.io.OutputStream) callback and sends a state to this node, the state receiver. After the state arrives to the state receiver MessageListener.setState(java.io.InputStream) callback is invoked to install the state.

覆盖:

getState 在类中 JChannel

参数:

target - The state provider. If null the coordinator is used by default

timeout - The number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received

抛出:

java.lang.IllegalStateException - The channel was closed or disconnected, or the flush (if present) failed

StateTransferException - raised if there was a problem during the state transfer

java.lang.Exception

另请参阅:

MessageListener.getState(java.io.OutputStream), MessageListener.setState(java.io.InputStream)

addAddressGenerator

public void addAddressGenerator(AddressGenerator address_generator)

从类复制的说明: JChannel

Sets the new AddressGenerator. New addresses will be generated using the new generator. This should not be done while a channel is connected, but before connecting.

覆盖:

addAddressGenerator 在类中 JChannel

setLocalAddress

protected void setLocalAddress(Address local_addr)

getFORK

protected static FORK getFORK(Channel ch,
           int position,
           java.lang.Class<? extends Protocol> neighbor,
           boolean create_fork_if_absent)
                       throws java.lang.Exception

抛出:

java.lang.Exception

getForkStack

protected static ForkProtocolStack getForkStack(Protocol prot)

setHeader

protected void setHeader(Message msg)

copyFields

protected void copyFields()

Copies state from main-channel to this fork-channel

nullFields

protected void nullFields()