Package org.jgroups.protocols
Class BARRIER
- java.lang.Object
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- org.jgroups.stack.Protocol
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- org.jgroups.protocols.BARRIER
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public class BARRIER extends Protocol
All messages up the stack have to go through a barrier (read lock, RL). By default, the barrier is open. When a CLOSE_BARRIER event is received, we close the barrier by acquiring a write lock (WL). This succeeds when all previous messages have completed (by releasing their RLs). Thus, when we have acquired the WL, we know that there are no pending messages processed.
When an OPEN_BARRIER event is received, we simply open the barrier again and let all messages pass in the up direction. This is done by releasing the WL.- Version:
- $Id: BARRIER.java,v 1.6.4.4 2008/05/22 13:23:06 belaban Exp $
- Author:
- Bela Ban
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Constructor Summary
Constructors Constructor Description BARRIER()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
destroy()
This method is called on aChannel.close()
.java.lang.Object
down(Event evt)
An event is to be sent down the stack.long
getMaxCloseTime()
java.lang.String
getName()
int
getNumberOfInFlightThreads()
void
init()
Called after instance has been created (null constructor) and before protocol is started.boolean
isClosed()
boolean
isOpenerScheduled()
boolean
setProperties(java.util.Properties props)
Configures the protocol initially.void
stop()
This method is called on aChannel.disconnect()
.java.lang.Object
up(Event evt)
An event was received from the layer below.-
Methods inherited from class org.jgroups.stack.Protocol
downThreadEnabled, dumpStats, enableStats, getDownProtocol, getProperties, getProtocolStack, getThreadFactory, getTransport, getUpProtocol, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStats, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, start, statsEnabled, upThreadEnabled
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Method Detail
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setProperties
public boolean setProperties(java.util.Properties props)
Description copied from class:Protocol
Configures the protocol initially. A configuration string consists of name=value items, separated by a ';' (semicolon), e.g.:"loopback=false;unicast_inport=4444"
- Overrides:
setProperties
in classProtocol
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isClosed
public boolean isClosed()
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isOpenerScheduled
public boolean isOpenerScheduled()
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getMaxCloseTime
public long getMaxCloseTime()
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getNumberOfInFlightThreads
public int getNumberOfInFlightThreads()
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init
public void init() throws java.lang.Exception
Description copied from class:Protocol
Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
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stop
public void stop()
Description copied from class:Protocol
This method is called on aChannel.disconnect()
. Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed
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destroy
public void destroy()
Description copied from class:Protocol
This method is called on aChannel.close()
. Does some cleanup; after the call the VM will terminate
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down
public java.lang.Object down(Event evt)
Description copied from class:Protocol
An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack usingdown_prot.down()
. In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack usingup_prot.up()
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up
public java.lang.Object up(Event evt)
Description copied from class:Protocol
An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack usingdown_prot.down()
or c) the event (or another event) is sent up the stack usingup_prot.up()
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