Package org.jgroups.blocks
Class MessageDispatcher
java.lang.Object
org.jgroups.blocks.MessageDispatcher
- All Implemented Interfaces:
RequestHandler
- Direct Known Subclasses:
RpcDispatcher
Provides synchronous and asynchronous message sending with request-response
correlation; i.e., matching responses with the original request.
It also offers push-style message reception (by internally using the PullPushAdapter).
Channels are simple patterns to asynchronously send a receive messages. However, a significant number of communication patterns in group communication require synchronous communication. For example, a sender would like to send a message to the group and wait for all responses. Or another application would like to send a message to the group and wait only until the majority of the receivers have sent a response, or until a timeout occurred. MessageDispatcher offers a combination of the above pattern with other patterns.
Used on top of channel to implement group requests. Client's handle()
method is called when request is received. Is the equivalent of RpcProtocol on
the application instead of protocol level.
- Version:
- $Id: MessageDispatcher.java,v 1.74.2.5 2008/12/05 14:49:54 belaban Exp $
- Author:
- Bela Ban
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected PullPushAdapter
protected Channel
protected boolean
Process items on the queue concurrently (RequestCorrelator).protected RequestCorrelator
protected boolean
protected org.jgroups.blocks.MessageDispatcher.PullPushHandler
protected Serializable
protected Address
protected final org.apache.commons.logging.Log
protected final Collection
protected MembershipListener
protected MessageListener
protected org.jgroups.blocks.MessageDispatcher.ProtocolAdapter
protected RequestHandler
protected org.jgroups.blocks.MessageDispatcher.TransportAdapter
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Constructor Summary
ConstructorsConstructorDescriptionMessageDispatcher
(PullPushAdapter adapter, Serializable id, MessageListener l, MembershipListener l2) MessageDispatcher
(PullPushAdapter adapter, Serializable id, MessageListener l, MembershipListener l2, RequestHandler req_handler) MessageDispatcher
(PullPushAdapter adapter, Serializable id, MessageListener l, MembershipListener l2, RequestHandler req_handler, boolean concurrent_processing) MessageDispatcher
(Channel channel, MessageListener l, MembershipListener l2) MessageDispatcher
(Channel channel, MessageListener l, MembershipListener l2, boolean deadlock_detection) MessageDispatcher
(Channel channel, MessageListener l, MembershipListener l2, boolean deadlock_detection, boolean concurrent_processing) MessageDispatcher
(Channel channel, MessageListener l, MembershipListener l2, RequestHandler req_handler) MessageDispatcher
(Channel channel, MessageListener l, MembershipListener l2, RequestHandler req_handler, boolean deadlock_detection) MessageDispatcher
(Channel channel, MessageListener l, MembershipListener l2, RequestHandler req_handler, boolean deadlock_detection, boolean concurrent_processing) -
Method Summary
Modifier and TypeMethodDescriptionvoid
castMessage
(Vector dests, long req_id, Message msg, RspCollector coll) Multicast a message request to all members indests
and receive responses via the RspCollector interface.castMessage
(Vector dests, Message msg, int mode, long timeout) castMessage
(Vector dests, Message msg, int mode, long timeout, boolean use_anycasting) Cast a message to all members, and wait formode
responses.castMessage
(Vector dests, Message msg, int mode, long timeout, boolean use_anycasting, RspFilter filter) protected void
void
done
(long req_id) Offers access to the underlying Channel.boolean
boolean
protected Collection
Returns a copy of membersGives access to the currently configured MessageListener.void
sendMessage
(Message msg, int mode, long timeout) Sends a message to a single member (destination = msg.dest) and returns the response.void
setChannel
(Channel ch) void
setConcurrentProcessing
(boolean flag) void
setDeadlockDetection
(boolean flag) final void
final void
final void
final void
start()
void
stop()
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Field Details
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channel
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corr
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msg_listener
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membership_listener
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req_handler
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prot_adapter
protected org.jgroups.blocks.MessageDispatcher.ProtocolAdapter prot_adapter -
transport_adapter
protected org.jgroups.blocks.MessageDispatcher.TransportAdapter transport_adapter -
members
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local_addr
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deadlock_detection
protected boolean deadlock_detection -
adapter
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handler
protected org.jgroups.blocks.MessageDispatcher.PullPushHandler handler -
id
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log
protected final org.apache.commons.logging.Log log -
concurrent_processing
protected boolean concurrent_processingProcess items on the queue concurrently (RequestCorrelator). The default is to wait until the processing of an item has completed before fetching the next item from the queue. Note that setting this to true may destroy the properties of a protocol stack, e.g total or causal order may not be guaranteed. Set this to true only if you know what you're doing !
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Constructor Details
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MessageDispatcher
public MessageDispatcher() -
MessageDispatcher
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MessageDispatcher
public MessageDispatcher(Channel channel, MessageListener l, MembershipListener l2, boolean deadlock_detection) -
MessageDispatcher
public MessageDispatcher(Channel channel, MessageListener l, MembershipListener l2, boolean deadlock_detection, boolean concurrent_processing) -
MessageDispatcher
public MessageDispatcher(Channel channel, MessageListener l, MembershipListener l2, RequestHandler req_handler) -
MessageDispatcher
public MessageDispatcher(Channel channel, MessageListener l, MembershipListener l2, RequestHandler req_handler, boolean deadlock_detection) -
MessageDispatcher
public MessageDispatcher(Channel channel, MessageListener l, MembershipListener l2, RequestHandler req_handler, boolean deadlock_detection, boolean concurrent_processing) -
MessageDispatcher
public MessageDispatcher(PullPushAdapter adapter, Serializable id, MessageListener l, MembershipListener l2) -
MessageDispatcher
public MessageDispatcher(PullPushAdapter adapter, Serializable id, MessageListener l, MembershipListener l2, RequestHandler req_handler) -
MessageDispatcher
public MessageDispatcher(PullPushAdapter adapter, Serializable id, MessageListener l, MembershipListener l2, RequestHandler req_handler, boolean concurrent_processing)
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Method Details
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getMembers
Returns a copy of members -
getDeadlockDetection
public boolean getDeadlockDetection() -
setDeadlockDetection
public void setDeadlockDetection(boolean flag) -
getConcurrentProcessing
public boolean getConcurrentProcessing() -
setConcurrentProcessing
public void setConcurrentProcessing(boolean flag) -
start
public final void start() -
correlatorStarted
protected void correlatorStarted() -
stop
public void stop() -
setMessageListener
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getMessageListener
Gives access to the currently configured MessageListener. Returns null if there is no configured MessageListener. -
setMembershipListener
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setRequestHandler
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getChannel
Offers access to the underlying Channel.- Returns:
- a reference to the underlying Channel.
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setChannel
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send
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castMessage
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castMessage
public RspList castMessage(Vector dests, Message msg, int mode, long timeout, boolean use_anycasting) Cast a message to all members, and wait formode
responses. The responses are returned in a response list, where each response is associated with its sender.Uses
GroupRequest
.- Parameters:
dests
- The members to which the message is to be sent. If it is null, then the message is sent to all membersmsg
- The message to be sent to n membersmode
- Defined inGroupRequest
. The number of responses to wait for:- GET_FIRST: return the first response received.
- GET_ALL: wait for all responses (minus the ones from suspected members)
- GET_MAJORITY: wait for a majority of all responses (relative to the grp size)
- GET_ABS_MAJORITY: wait for majority (absolute, computed once)
- GET_N: wait for n responses (may block if n > group size)
- GET_NONE: wait for no responses, return immediately (non-blocking)
timeout
- If 0: wait forever. Otherwise, wait formode
responses or timeout time.- Returns:
- RspList A list of responses. Each response is an
Object
and associated to its sender.
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castMessage
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castMessage
Multicast a message request to all members indests
and receive responses via the RspCollector interface. When done receiving the required number of responses, the caller has to call done(req_id) on the underlyinh RequestCorrelator, so that the resources allocated to that request can be freed.- Parameters:
dests
- The list of members from which to receive responses. Null means all membersreq_id
- The ID of the request. Used by the underlying RequestCorrelator to correlate responses with requestsmsg
- The request to be sentcoll
- The sender needs to provide this interface to collect responses. Call will return immediately if this is null
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done
public void done(long req_id) -
sendMessage
public Object sendMessage(Message msg, int mode, long timeout) throws TimeoutException, SuspectedException Sends a message to a single member (destination = msg.dest) and returns the response. The message's destination must be non-zero !- Throws:
TimeoutException
SuspectedException
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handle
- Specified by:
handle
in interfaceRequestHandler
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