Class JChannel
- java.lang.Object
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- org.jgroups.Channel
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- org.jgroups.JChannel
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- All Implemented Interfaces:
Transport
- Direct Known Subclasses:
MuxChannel
public class JChannel extends Channel
JChannel is a pure Java implementation of Channel. When a JChannel object is instantiated it automatically sets up the protocol stack.Properties
Properties are used to configure a channel, and are accepted in several forms; the String form is described here. A property string consists of a number of properties separated by colons. For example:
"<prop1>(arg1=val1):<prop2>(arg1=val1;arg2=val2):<prop3>:<propn>"
Each property relates directly to a protocol layer, which is implemented as a Java class. When a protocol stack is to be created based on the above property string, the first property becomes the bottom-most layer, the second one will be placed on the first, etc.: the stack is created from the bottom to the top, as the string is parsed from left to right. Each property has to be the name of a Java class that resides in the
org.jgroups.protocols
package.Note that only the base name has to be given, not the fully specified class name (e.g., UDP instead of org.jgroups.protocols.UDP).
Each layer may have 0 or more arguments, which are specified as a list of name/value pairs in parentheses directly after the property. In the example above, the first protocol layer has 1 argument, the second 2, the third none. When a layer is created, these properties (if there are any) will be set in a layer by invoking the layer's setProperties() method
As an example the property string below instructs JGroups to create a JChannel with protocols UDP, PING, FD and GMS:
"UDP(mcast_addr=228.10.9.8;mcast_port=5678):PING:FD:GMS"
The UDP protocol layer is at the bottom of the stack, and it should use mcast address 228.10.9.8. and port 5678 rather than the default IP multicast address and port. The only other argument instructs FD to output debug information while executing. Property UDP refers to a class
UDP
, which is subsequently loaded and an instance of which is created as protocol layer. If any of these classes are not found, an exception will be thrown and the construction of the stack will be aborted.- Version:
- $Id: JChannel.java,v 1.158.2.25 2009/03/30 12:35:18 belaban Exp $
- Author:
- Bela Ban
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Field Summary
Fields Modifier and Type Field Description protected java.util.Map<java.lang.String,java.lang.Object>
additional_data
Provides storage for arbitrary objects.protected boolean
closed
protected org.jgroups.JChannel.CloserThread
closer
Thread responsible for closing a channel and potentially reconnecting to it (e.g., when shunned).protected boolean
connected
static java.lang.String
DEFAULT_PROTOCOL_STACK
The default protocol stack used by the default constructor.protected java.util.concurrent.ConcurrentMap<java.lang.String,java.lang.Object>
info
protected org.apache.commons.logging.Log
log
protected long
received_bytes
protected long
received_msgs
protected long
sent_bytes
protected long
sent_msgs
protected boolean
stats
Collect statistics-
Fields inherited from class org.jgroups.Channel
AUTO_GETSTATE, AUTO_RECONNECT, BLOCK, channel_listeners, GET_STATE_EVENTS, LOCAL, receiver, SUSPECT, up_handler, VIEW
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Constructor Summary
Constructors Modifier Constructor Description JChannel()
Constructs aJChannel
instance with the protocol stack specified by theDEFAULT_PROTOCOL_STACK
member.protected
JChannel(boolean no_op)
Used by subclass to create a JChannel without a protocol stack, don't use as application programmerJChannel(java.io.File properties)
Constructs aJChannel
instance with the protocol stack configuration contained by the specified file.JChannel(java.lang.Object properties)
Deprecated.Use the constructors with specific parameter types instead.JChannel(java.lang.String properties)
Constructs aJChannel
instance with the protocol stack configuration based upon the specified properties parameter.JChannel(java.net.URL properties)
Constructs aJChannel
instance with the protocol stack configuration indicated by the specified URL.JChannel(ProtocolStackConfigurator configurator)
Constructs aJChannel
instance with the protocol stack configuration contained by the protocol stack configurator parameter.JChannel(org.w3c.dom.Element properties)
Constructs aJChannel
instance with the protocol stack configuration contained by the specified XML element.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description protected void
_close(boolean disconnect, boolean close_mq)
Disconnects and closes the channel.void
blockOk()
Called to acknowledge a block() (callback inMembershipListener
orBlockEvent
received from call toreceive()
).protected void
checkClosed()
health check
throws a ChannelClosed exception if the channel is closedprotected void
checkClosedOrNotConnected()
void
close()
Destroys the channel.void
closeMessageQueue(boolean flush_entries)
void
connect(java.lang.String cluster_name)
Connects the channel to a group.void
connect(java.lang.String cluster_name, Address target, java.lang.String state_id, long timeout)
Connects this channel to a group and gets a state from a specified state provider.void
disconnect()
Disconnects the channel if it is connected.void
down(Event evt)
Sends a message through the protocol stack if the stack is availablejava.lang.Object
downcall(Event evt)
Can be used instead of down() when a return value is expected.protected java.util.Map<java.lang.String,java.lang.Long>
dumpChannelStats()
java.lang.String
dumpQueue()
java.util.Map<java.lang.String,java.lang.Object>
dumpStats()
Returns a map of statistics of the various protocols and of the channel itself.java.util.Map<java.lang.String,java.lang.Object>
dumpStats(java.lang.String protocol_name)
java.lang.String
dumpTimerQueue()
void
enableStats(boolean stats)
boolean
flushSupported()
boolean
getAllStates(java.util.Vector targets, long timeout)
Deprecated.Not really needed - we always want to get the state from a single member, usegetState(org.jgroups.Address, long)
insteadjava.lang.String
getChannelName()
Deprecated.UsegetClusterName()
insteadjava.lang.String
getClusterName()
Returns the cluster name of the group of which the channel is a member.java.util.Map<java.lang.String,java.lang.Object>
getInfo()
Address
getLocalAddress()
returns the local address of the channel returns null if the channel is closedjava.lang.String
getLocalAddressAsString()
protected org.apache.commons.logging.Log
getLog()
int
getNumberOfTasksInTimer()
int
getNumMessages()
Returns the number of messages that are waiting.java.lang.Object
getOpt(int option)
returns the value of an option.java.lang.String
getProperties()
returns the protocol stack configuration in string format.ProtocolStack
getProtocolStack()
Returns the protocol stack.long
getReceivedBytes()
long
getReceivedMessages()
long
getSentBytes()
long
getSentMessages()
boolean
getState(Address target, long timeout)
Retrieves a full state from the target member.boolean
getState(Address target, java.lang.String state_id, long timeout)
Retrieves a substate (or partial state) indicated by state_id from the target member.boolean
getState(Address target, java.lang.String state_id, long timeout, boolean useFlushIfPresent)
Retrieves a substate (or partial state) indicated by state_id from the target member.protected boolean
getState(Address target, java.lang.String state_id, long timeout, java.util.concurrent.Callable<java.lang.Boolean> flushInvoker)
Retrieves a substate (or partial state) indicated by state_id from the target member.int
getTimerThreads()
View
getView()
Returns the current view.protected void
init(ProtocolStackConfigurator configurator)
boolean
isConnected()
returns true if the Connect operation has been called successfullyboolean
isOpen()
returns true if the Open operation has been called successfullyvoid
open()
Opens the channel.java.lang.Object
peek(long timeout)
Just peeks at the next message, view or block.java.lang.String
printProtocolSpec(boolean include_properties)
Returns a pretty-printed form of all the protocols.java.lang.Object
receive(long timeout)
Deprecated.Use aReceiver
insteadvoid
resetStats()
void
returnState(byte[] state)
Called by the application is response to receiving agetState()
object when callingreceive()
.void
returnState(byte[] state, java.lang.String state_id)
Returns a substate as indicated by state_idvoid
send(Address dst, Address src, java.io.Serializable obj)
creates a new message with the destination address, and the source address and the object as the message valuevoid
send(Message msg)
Sends a message through the protocol stack.void
setInfo(java.lang.String key, java.lang.Object value)
void
setOpt(int option, java.lang.Object value)
Sets a channel option.void
shutdown()
Shuts down the channel without disconnectingboolean
startFlush(boolean automatic_resume)
Will perform a flush of the system, ie.boolean
startFlush(long timeout, boolean automatic_resume)
Will perform a flush of the system, ie.boolean
startFlush(java.util.List<Address> flushParticipants, boolean automatic_resume)
Performs a partial flush in a cluster for flush participants.boolean
statsEnabled()
void
stopFlush()
void
stopFlush(java.util.List<Address> flushParticipants)
protected void
stopStack(boolean disconnect, boolean destroy)
java.lang.String
toString(boolean details)
java.lang.Object
up(Event evt)
Callback method
Called by the ProtocolStack when a message is received.-
Methods inherited from class org.jgroups.Channel
addChannelListener, clearChannelListeners, getReceiver, notifyChannelClosed, notifyChannelConnected, notifyChannelDisconnected, notifyChannelReconnected, notifyChannelShunned, option2String, removeChannelListener, setChannelListener, setReceiver, setUpHandler
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Field Detail
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DEFAULT_PROTOCOL_STACK
public static final java.lang.String DEFAULT_PROTOCOL_STACK
The default protocol stack used by the default constructor.- See Also:
- Constant Field Values
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closer
protected org.jgroups.JChannel.CloserThread closer
Thread responsible for closing a channel and potentially reconnecting to it (e.g., when shunned).
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connected
protected volatile boolean connected
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closed
protected volatile boolean closed
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additional_data
protected final java.util.Map<java.lang.String,java.lang.Object> additional_data
Provides storage for arbitrary objects. Protocols can send up CONFIG events, and all key-value pairs of a CONFIG event will be added to additional_data. On reconnect, a CONFIG event will be sent down by the channel, containing all key-value pairs of additional_data
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info
protected final java.util.concurrent.ConcurrentMap<java.lang.String,java.lang.Object> info
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log
protected final org.apache.commons.logging.Log log
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stats
protected boolean stats
Collect statistics
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sent_msgs
protected long sent_msgs
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received_msgs
protected long received_msgs
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sent_bytes
protected long sent_bytes
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received_bytes
protected long received_bytes
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Constructor Detail
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JChannel
protected JChannel(boolean no_op)
Used by subclass to create a JChannel without a protocol stack, don't use as application programmer
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JChannel
public JChannel() throws ChannelException
Constructs aJChannel
instance with the protocol stack specified by theDEFAULT_PROTOCOL_STACK
member.- Throws:
ChannelException
- if problems occur during the initialization of the protocol stack.
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JChannel
public JChannel(java.io.File properties) throws ChannelException
Constructs aJChannel
instance with the protocol stack configuration contained by the specified file.- Parameters:
properties
- a file containing a JGroups XML protocol stack configuration.- Throws:
ChannelException
- if problems occur during the configuration or initialization of the protocol stack.
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JChannel
public JChannel(org.w3c.dom.Element properties) throws ChannelException
Constructs aJChannel
instance with the protocol stack configuration contained by the specified XML element.- Parameters:
properties
- a XML element containing a JGroups XML protocol stack configuration.- Throws:
ChannelException
- if problems occur during the configuration or initialization of the protocol stack.
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JChannel
public JChannel(java.net.URL properties) throws ChannelException
Constructs aJChannel
instance with the protocol stack configuration indicated by the specified URL.- Parameters:
properties
- a URL pointing to a JGroups XML protocol stack configuration.- Throws:
ChannelException
- if problems occur during the configuration or initialization of the protocol stack.
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JChannel
public JChannel(java.lang.String properties) throws ChannelException
Constructs aJChannel
instance with the protocol stack configuration based upon the specified properties parameter.- Parameters:
properties
- an old style property string, a string representing a system resource containing a JGroups XML configuration, a string representing a URL pointing to a JGroups XML XML configuration, or a string representing a file name that contains a JGroups XML configuration.- Throws:
ChannelException
- if problems occur during the configuration and initialization of the protocol stack.
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JChannel
public JChannel(ProtocolStackConfigurator configurator) throws ChannelException
Constructs aJChannel
instance with the protocol stack configuration contained by the protocol stack configurator parameter.All of the public constructors of this class eventually delegate to this method.
- Parameters:
configurator
- a protocol stack configurator containing a JGroups protocol stack configuration.- Throws:
ChannelException
- if problems occur during the initialization of the protocol stack.
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JChannel
public JChannel(java.lang.Object properties) throws ChannelException
Deprecated.Use the constructors with specific parameter types instead.Creates a new JChannel with the protocol stack as defined in the properties parameter. an example of this parameter is
"UDP:PING:FD:STABLE:NAKACK:UNICAST:FRAG:FLUSH:GMS:VIEW_ENFORCER:STATE_TRANSFER:QUEUE"
Other examples can be found in the ./conf directory- Parameters:
properties
- the protocol stack setup; if null, the default protocol stack will be used. The properties can also be a java.net.URL object or a string that is a URL spec. The JChannel will validate any URL object and String object to see if they are a URL. In case of the parameter being a url, the JChannel will try to load the xml from there. In case properties is a org.w3c.dom.Element, the ConfiguratorFactory will parse the DOM tree with the element as its root element.- Throws:
ChannelException
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Method Detail
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getProtocolStack
public ProtocolStack getProtocolStack()
Returns the protocol stack. Currently used by Debugger. Specific to JChannel, therefore not visible in Channel
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getProperties
public java.lang.String getProperties()
returns the protocol stack configuration in string format. an example of this property is
"UDP:PING:FD:STABLE:NAKACK:UNICAST:FRAG:FLUSH:GMS:VIEW_ENFORCER:STATE_TRANSFER:QUEUE"
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statsEnabled
public boolean statsEnabled()
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enableStats
public void enableStats(boolean stats)
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resetStats
public void resetStats()
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getSentMessages
public long getSentMessages()
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getSentBytes
public long getSentBytes()
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getReceivedMessages
public long getReceivedMessages()
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getReceivedBytes
public long getReceivedBytes()
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getNumberOfTasksInTimer
public int getNumberOfTasksInTimer()
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getTimerThreads
public int getTimerThreads()
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dumpTimerQueue
public java.lang.String dumpTimerQueue()
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printProtocolSpec
public java.lang.String printProtocolSpec(boolean include_properties)
Returns a pretty-printed form of all the protocols. If include_properties is set, the properties for each protocol will also be printed.
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connect
public void connect(java.lang.String cluster_name) throws ChannelException
Connects the channel to a group. If the channel is already connected, an error message will be printed to the error log. If the channel is closed a ChannelClosed exception will be thrown. This method starts the protocol stack by calling ProtocolStack.start, then it sends an Event.CONNECT event down the stack and waits for the return value. Once the call returns, the channel listeners are notified and the channel is considered connected.- Specified by:
connect
in classChannel
- Parameters:
cluster_name
- AString
denoting the group name. Cannot be null.- Throws:
ChannelException
- The protocol stack cannot be startedChannelClosedException
- The channel is closed and therefore cannot be used any longer. A new channel has to be created first.- See Also:
Channel.disconnect()
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connect
public void connect(java.lang.String cluster_name, Address target, java.lang.String state_id, long timeout) throws ChannelException
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 succesion. If the channel is already connected, an error message will be printed to the error log. If the channel is closed a ChannelClosed exception will be thrown.
- Specified by:
connect
in classChannel
- Parameters:
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.state_id
- the substate id for partial state transfer. If null entire state will be transferred.timeout
- the timeout for state transfer.- Throws:
ChannelException
- The protocol stack cannot be startedChannelException
- Connecting to cluster was not successfulChannelClosedException
- The channel is closed and therefore cannot be used any longer. A new channel has to be created first.StateTransferException
- State transfer was not successful
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disconnect
public void disconnect()
Disconnects the channel if it is connected. If the channel is closed, this operation is ignored
Otherwise the following actions happen in the listed order
- The JChannel sends a DISCONNECT event down the protocol stack
- Blocks until the event has returned
- Sends a STOP_QUEING event down the stack
- Stops the protocol stack by calling ProtocolStack.stop()
- Notifies the listener, if the listener is available
- Specified by:
disconnect
in classChannel
- See Also:
Channel.connect(String)
- The JChannel sends a DISCONNECT event down the protocol stack
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close
public void close()
Destroys the channel. After this method has been called, the channel us unusable.
This operation will disconnect the channel and close the channel receive queue immediately
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shutdown
public void shutdown()
Shuts down the channel without disconnecting
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open
public void open() throws ChannelException
Opens the channel. Note that the channel is only open, but not connected. This does the following actions:- Resets the receiver queue by calling Queue.reset
- Sets up the protocol stack by calling ProtocolStack.setup
- Sets the closed flag to false
- Overrides:
open
in classChannel
- Throws:
ChannelException
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isOpen
public boolean isOpen()
returns true if the Open operation has been called successfully
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isConnected
public boolean isConnected()
returns true if the Connect operation has been called successfully- Specified by:
isConnected
in classChannel
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getNumMessages
public int getNumMessages()
Description copied from class:Channel
Returns the number of messages that are waiting. Those messages can be removed byChannel.receive(long)
. Note that this number could change after calling this method and before calling receive() (e.g. the latter method might be called by a different thread).- Overrides:
getNumMessages
in classChannel
- Returns:
- The number of messages on the queue, or -1 if the queue/channel is closed/disconnected.
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dumpStats
public java.util.Map<java.lang.String,java.lang.Object> dumpStats()
Returns a map of statistics of the various protocols and of the channel itself.
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dumpStats
public java.util.Map<java.lang.String,java.lang.Object> dumpStats(java.lang.String protocol_name)
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dumpChannelStats
protected java.util.Map<java.lang.String,java.lang.Long> dumpChannelStats()
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send
public void send(Message msg) throws ChannelNotConnectedException, ChannelClosedException
Sends a message through the protocol stack. Implements the Transport interface.- Specified by:
send
in interfaceTransport
- Specified by:
send
in classChannel
- Parameters:
msg
- the message to be sent through the protocol stack, the destination of the message is specified inside the message itself- Throws:
ChannelNotConnectedException
ChannelClosedException
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send
public void send(Address dst, Address src, java.io.Serializable obj) throws ChannelNotConnectedException, ChannelClosedException
creates a new message with the destination address, and the source address and the object as the message value- Specified by:
send
in classChannel
- Parameters:
dst
- - the destination address of the message, null for all memberssrc
- - the source address of the messageobj
- - the value of the message- Throws:
ChannelNotConnectedException
ChannelClosedException
- See Also:
send(org.jgroups.Message)
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receive
public java.lang.Object receive(long timeout) throws ChannelNotConnectedException, ChannelClosedException, TimeoutException
Deprecated.Use aReceiver
insteadBlocking receive method. This method returns the object that was first received by this JChannel and that has not been received before. After the object is received, it is removed from the receive queue.
If you only want to inspect the object received without removing it from the queue call JChannel.peek
If no messages are in the receive queue, this method blocks until a message is added or the operation times out
By specifying a timeout of 0, the operation blocks forever, or until a message has been received.- Specified by:
receive
in interfaceTransport
- Specified by:
receive
in classChannel
- Parameters:
timeout
- the number of milliseconds to wait if the receive queue is empty. 0 means wait forever- Returns:
- A Message, View, BlockEvent, SuspectEvent, GetStateEvent, SetStateEvent or ExitEvent, depending on what is on top of the internal queue.
- Throws:
TimeoutException
- if a timeout occured prior to a new message was receivedChannelNotConnectedException
ChannelClosedException
- See Also:
peek(long)
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peek
public java.lang.Object peek(long timeout) throws ChannelNotConnectedException, ChannelClosedException, TimeoutException
Just peeks at the next message, view or block. Does not install new view if view is received
Does the same thing as JChannel.receive but doesn't remove the object from the receiver queue- Specified by:
peek
in classChannel
- Parameters:
timeout
- Value in milliseconds. Value <= 0 means wait forever- Returns:
- A Message, View, BlockEvent, SuspectEvent, GetStateEvent or SetStateEvent object, depending on what is on top of the internal queue.
- Throws:
ChannelNotConnectedException
- The channel must be connected to receive messages.ChannelClosedException
- The channel is closed and therefore cannot be used any longer. A new channel has to be created first.TimeoutException
- Thrown when a timeout has occurred.- See Also:
Channel.receive(long)
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getView
public View getView()
Returns the current view.
If the channel is not connected or if it is closed it will return null.
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getLocalAddress
public Address getLocalAddress()
returns the local address of the channel returns null if the channel is closed- Specified by:
getLocalAddress
in classChannel
- Returns:
- The channel's address. Generated by the underlying transport, and opaque.
Addresses can be used as destination in the
Send
operation.
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getLocalAddressAsString
public java.lang.String getLocalAddressAsString()
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getChannelName
public java.lang.String getChannelName()
Deprecated.UsegetClusterName()
insteadreturns the name of the channel if the channel is not connected or if it is closed it will return null- Specified by:
getChannelName
in classChannel
- Returns:
- The group address
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getClusterName
public java.lang.String getClusterName()
Description copied from class:Channel
Returns the cluster name of the group of which the channel is a member. This is the object that was the argument toconnect()
. Calling this method on a closed channel returnsnull
.- Specified by:
getClusterName
in classChannel
- Returns:
- The cluster name
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setOpt
public void setOpt(int option, java.lang.Object value)
Sets a channel option. The options can be one of the following:- Channel.BLOCK
- Channel.LOCAL
- Channel.AUTO_RECONNECT
- Channel.AUTO_GETSTATE
There are certain dependencies between the options that you can set, I will try to describe them here.
Option: Channel.BLOCK
Value: java.lang.Boolean
Result: set to true will set setOpt(VIEW, true) and the JChannel will receive BLOCKS and VIEW events
Option: LOCAL
Value: java.lang.Boolean
Result: set to true the JChannel will receive messages that it self sent out.
Option: AUTO_RECONNECT
Value: java.lang.Boolean
Result: set to true and the JChannel will try to reconnect when it is being closed
Option: AUTO_GETSTATE
Value: java.lang.Boolean
Result: set to true, the AUTO_RECONNECT will be set to true and the JChannel will try to get the state after a close and reconnect happens
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getOpt
public java.lang.Object getOpt(int option)
returns the value of an option.- Specified by:
getOpt
in classChannel
- Parameters:
option
- the option you want to see the value for- Returns:
- the object value, in most cases java.lang.Boolean
- See Also:
setOpt(int, java.lang.Object)
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blockOk
public void blockOk()
Called to acknowledge a block() (callback inMembershipListener
orBlockEvent
received from call toreceive()
). After sending blockOk(), no messages should be sent until a new view has been received. Calling this method on a closed channel has no effect.
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getState
public boolean getState(Address target, long timeout) throws ChannelNotConnectedException, ChannelClosedException
Retrieves a full state from the target member.State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.
- Specified by:
getState
in classChannel
- Parameters:
target
- State provider. If null, coordinator is usedstate_id
- The ID of the substate. If null, the entire state will be transferredtimeout
- the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received- Returns:
- true if state transfer was successful, false otherwise
- Throws:
ChannelNotConnectedException
- if channel was not connected at the time state retrieval was initiatedChannelClosedException
- if channel was closed at the time state retrieval was initiatedjava.lang.IllegalStateException
- if one of state transfer protocols is not present in this channeljava.lang.IllegalStateException
- if flush is used in this channel and cluster could not be flushed- See Also:
ExtendedMessageListener.getState(OutputStream)
,ExtendedMessageListener.setState(InputStream)
,MessageListener.getState()
,MessageListener.setState(byte[])
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getState
public boolean getState(Address target, java.lang.String state_id, long timeout) throws ChannelNotConnectedException, ChannelClosedException
Retrieves a substate (or partial state) indicated by state_id from the target member.State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.
- Specified by:
getState
in classChannel
- Parameters:
target
- State provider. If null, coordinator is usedstate_id
- The ID of the substate. If null, the entire state will be transferredtimeout
- the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received- Returns:
- true if state transfer was successful, false otherwise
- Throws:
ChannelNotConnectedException
- if channel was not connected at the time state retrieval was initiatedChannelClosedException
- if channel was closed at the time state retrieval was initiatedjava.lang.IllegalStateException
- if one of state transfer protocols is not present in this channeljava.lang.IllegalStateException
- if flush is used in this channel and cluster could not be flushed- See Also:
ExtendedMessageListener.getState(OutputStream)
,ExtendedMessageListener.setState(InputStream)
,MessageListener.getState()
,MessageListener.setState(byte[])
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getState
public boolean getState(Address target, java.lang.String state_id, long timeout, boolean useFlushIfPresent) throws ChannelNotConnectedException, ChannelClosedException
Retrieves a substate (or partial state) indicated by state_id from the target member.State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.
- Parameters:
target
- State provider. If null, coordinator is usedstate_id
- The ID of the substate. If null, the entire state will be transferredtimeout
- the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been receiveduseFlushIfPresent
- whether channel should be flushed prior to state retrieval- Returns:
- true if state transfer was successful, false otherwise
- Throws:
ChannelNotConnectedException
- if channel was not connected at the time state retrieval was initiatedChannelClosedException
- if channel was closed at the time state retrieval was initiatedjava.lang.IllegalStateException
- if one of state transfer protocols is not present in this channeljava.lang.IllegalStateException
- if flush is used in this channel and cluster could not be flushed- See Also:
ExtendedMessageListener.getState(OutputStream)
,ExtendedMessageListener.setState(InputStream)
,MessageListener.getState()
,MessageListener.setState(byte[])
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getState
protected boolean getState(Address target, java.lang.String state_id, long timeout, java.util.concurrent.Callable<java.lang.Boolean> flushInvoker) throws ChannelNotConnectedException, ChannelClosedException
Retrieves a substate (or partial state) indicated by state_id from the target member.State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.
- Parameters:
target
- State provider. If null, coordinator is usedstate_id
- The ID of the substate. If null, the entire state will be transferredtimeout
- the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been receivedflushInvoker
- algorithm invoking flush- Returns:
- true if state transfer was successful, false otherwise
- Throws:
ChannelNotConnectedException
- if channel was not connected at the time state retrieval was initiatedChannelClosedException
- if channel was closed at the time state retrieval was initiatedjava.lang.IllegalStateException
- if one of state transfer protocols is not present in this channeljava.lang.IllegalStateException
- if flush is used in this channel and cluster could not be flushed- See Also:
ExtendedMessageListener.getState(OutputStream)
,ExtendedMessageListener.setState(InputStream)
,MessageListener.getState()
,MessageListener.setState(byte[])
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getAllStates
public boolean getAllStates(java.util.Vector targets, long timeout) throws ChannelNotConnectedException, ChannelClosedException
Deprecated.Not really needed - we always want to get the state from a single member, usegetState(org.jgroups.Address, long)
insteadRetrieves the current group state. Sends GET_STATE event down to STATE_TRANSFER layer. Blocks until STATE_TRANSFER sends up a GET_STATE_OK event or untiltimeout
milliseconds have elapsed. The argument of GET_STATE_OK should be a vector of objects.- Specified by:
getAllStates
in classChannel
- Parameters:
targets
- - the target members to receive the state from ( an Address list )timeout
- - the number of milliseconds to wait for the operation to complete successfully- Returns:
- true of the state was received, false if the operation timed out
- Throws:
ChannelNotConnectedException
- The channel must be connected to receive messages.ChannelClosedException
- The channel is closed and therefore cannot be used any longer. A new channel has to be created first.
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returnState
public void returnState(byte[] state)
Called by the application is response to receiving agetState()
object when callingreceive()
. When the application receives a getState() message on the receive() method, it should call returnState() to reply with the state of the application- Specified by:
returnState
in classChannel
- Parameters:
state
- The state of the application as a byte buffer (to send over the network).
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returnState
public void returnState(byte[] state, java.lang.String state_id)
Returns a substate as indicated by state_id- Specified by:
returnState
in classChannel
- Parameters:
state
-state_id
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up
public java.lang.Object up(Event evt)
Callback method
Called by the ProtocolStack when a message is received. It will be added to the message queue from which subsequentReceive
s will dequeue it.- Parameters:
evt
- the event carrying the message from the protocol stack
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down
public void down(Event evt)
Sends a message through the protocol stack if the stack is available
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downcall
public java.lang.Object downcall(Event evt)
Description copied from class:Channel
Can be used instead of down() when a return value is expected. This will be removed in 3.0 when we change the signature of down() to return Object rather than void
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toString
public java.lang.String toString(boolean details)
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init
protected final void init(ProtocolStackConfigurator configurator) throws ChannelException
- Throws:
ChannelException
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checkClosed
protected void checkClosed() throws ChannelClosedException
health check
throws a ChannelClosed exception if the channel is closed- Throws:
ChannelClosedException
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checkClosedOrNotConnected
protected void checkClosedOrNotConnected() throws ChannelNotConnectedException, ChannelClosedException
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_close
protected void _close(boolean disconnect, boolean close_mq)
Disconnects and closes the channel. This method does the following things- Calls
this.disconnect
if the disconnect parameter is true - Calls
Queue.close
on mq if the close_mq parameter is true - Calls
ProtocolStack.stop
on the protocol stack - Calls
ProtocolStack.destroy
on the protocol stack - Sets the channel closed and channel connected flags to true and false
- Notifies any channel listener of the channel close operation
- Calls
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stopStack
protected void stopStack(boolean disconnect, boolean destroy)
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closeMessageQueue
public final void closeMessageQueue(boolean flush_entries)
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flushSupported
public boolean flushSupported()
- Specified by:
flushSupported
in classChannel
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startFlush
public boolean startFlush(boolean automatic_resume)
Will perform a flush of the system, ie. all pending messages are flushed out of the system and all members ack their reception. After this call returns, no member will be sending any messages untilstopFlush()
is called.In case of flush collisions, random sleep time backoff algorithm is employed and flush is reattempted for numberOfAttempts. Therefore this method is guaranteed to return after timeout x numberOfAttempts miliseconds.
- Specified by:
startFlush
in classChannel
- Parameters:
automatic_resume
- CallstopFlush()
after the flush- Returns:
- true if FLUSH completed within the timeout
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startFlush
public boolean startFlush(java.util.List<Address> flushParticipants, boolean automatic_resume)
Performs a partial flush in a cluster for flush participants.All pending messages are flushed out only for flush participants. Remaining members in a cluster are not included in flush. Flush participants should be a proper subset of a current view.
In case of flush collisions, random sleep time backoff algorithm is employed and flush is reattempted for numberOfAttempts. Therefore this method is guaranteed to return after timeout x numberOfAttempts miliseconds.
- Specified by:
startFlush
in classChannel
- Parameters:
automatic_resume
- CallstopFlush()
after the flush- Returns:
- true if FLUSH completed within the timeout
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startFlush
public boolean startFlush(long timeout, boolean automatic_resume)
Will perform a flush of the system, ie. all pending messages are flushed out of the system and all members ack their reception. After this call returns, no member will be sending any messages untilstopFlush()
is called.In case of flush collisions, random sleep time backoff algorithm is employed and flush is reattempted for numberOfAttempts. Therefore this method is guaranteed to return after timeout x numberOfAttempts miliseconds.
- Specified by:
startFlush
in classChannel
- Parameters:
timeout
-automatic_resume
- CallstopFlush()
after the flush- Returns:
- true if FLUSH completed within the timeout
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stopFlush
public void stopFlush(java.util.List<Address> flushParticipants)
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getInfo
public java.util.Map<java.lang.String,java.lang.Object> getInfo()
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