org.jgroups.protocols.pbcast

Class Merger

java.lang.Object

org.jgroups.protocols.pbcast.Merger

public class Merger
extends java.lang.Object

Handles merging. Called by CoordGmsImpl and ParticipantGmsImpl

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	Merger.MergeKiller
protected class	Merger.MergeTask Starts the merge protocol (only run by the merge leader).

Field Summary

Fields

Modifier and Type	Field and Description
protected ResponseCollector<Digest>	digest_collector For GET_DIGEST / DIGEST_RSP correlation
protected GMS	gms
protected Log	log
protected MergeId	merge_id
protected BoundedList<MergeId>	merge_id_history
protected java.util.concurrent.Future<?>	merge_killer
protected ResponseCollector<MergeData>	merge_rsps For MERGE_REQ/MERGE_RSP correlation, contains MergeData elements
protected Merger.MergeTask	merge_task

Constructor Summary

Constructors

Constructor and Description
Merger(GMS gms)

Method Summary

Modifier and Type	Method and Description
protected void	_handleMergeRequest(Address sender, MergeId merge_id, java.util.Collection<? extends Address> mbrs)
protected void	cancelMerge(MergeId id)
protected static java.util.Map<Address,java.util.Collection<Address>>	determineMergeCoords(java.util.Map<Address,View> views) Needs to return a map of all subview coordinators and their views (as a collection of members).
protected Address	determineMergeLeader(java.util.Map<Address,View> views) Returns the address of the merge leader
protected Digest	fetchDigestsFromAllMembersInSubPartition(View view, MergeId merge_id) Multicasts a GET_DIGEST_REQ to all members of this sub partition and waits for all responses (GET_DIGEST_RSP) or N ms.
protected void	fixDigests() Fetches the digests from all members and installs them again.
protected void	forceCancelMerge()
MergeId	getMergeId()
java.lang.String	getMergeIdAsString()
java.lang.String	getMergeIdHistory()
void	handleDigestResponse(Address sender, Digest digest)
void	handleMergeCancelled(MergeId merge_id)
void	handleMergeRequest(Address sender, MergeId merge_id, java.util.Collection<? extends Address> mbrs) Get the view and digest and send back both (MergeData) in the form of a MERGE_RSP to the sender.
void	handleMergeResponse(MergeData data, MergeId merge_id)
void	handleMergeView(MergeData data, MergeId merge_id) If merge_id is not equal to this.merge_id then discard.
boolean	isMergeInProgress()
boolean	isMergeKillerTaskRunning()
boolean	isMergeTaskRunning()
boolean	matchMergeId(MergeId id)
void	merge(java.util.Map<Address,View> views) Invoked upon receiving a MERGE event from the MERGE layer.
static void	sanitizeViews(java.util.Map<Address,View> map) Removes all members from a given view which don't have us in their view (https://jira.jboss.org/browse/JGRP-1061).
protected void	sendMergeCancelledMessage(java.util.Collection<Address> coords, MergeId merge_id)
protected void	sendMergeRejectedResponse(Address sender, MergeId merge_id)
protected void	sendMergeResponse(Address sender, View view, Digest digest, MergeId merge_id) Send back a response containing view and digest to sender
protected void	sendMergeView(java.util.Collection<Address> coords, MergeData combined_merge_data, MergeId merge_id) Sends the new view and digest to all subgroup coordinors in coords.
boolean	setMergeId(MergeId expected, MergeId new_value)
protected void	startMergeKiller()
protected void	stop()
protected void	stopMergeKiller()

Methods inherited from class java.lang.Object

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

Field Detail

gms

protected final GMS gms

log

protected final Log log

merge_task

protected final Merger.MergeTask merge_task

merge_rsps

protected final ResponseCollector<MergeData> merge_rsps

For MERGE_REQ/MERGE_RSP correlation, contains MergeData elements

digest_collector

protected final ResponseCollector<Digest> digest_collector

For GET_DIGEST / DIGEST_RSP correlation

merge_id

protected MergeId merge_id

merge_id_history

protected final BoundedList<MergeId> merge_id_history

merge_killer

protected java.util.concurrent.Future<?> merge_killer

Constructor Detail

Merger

public Merger(GMS gms)

Method Detail

getMergeIdAsString

public java.lang.String getMergeIdAsString()

getMergeIdHistory

public java.lang.String getMergeIdHistory()

isMergeTaskRunning

public boolean isMergeTaskRunning()

isMergeKillerTaskRunning

public boolean isMergeKillerTaskRunning()

getMergeId

public MergeId getMergeId()

isMergeInProgress

public boolean isMergeInProgress()

matchMergeId

public boolean matchMergeId(MergeId id)

setMergeId

public boolean setMergeId(MergeId expected,
                          MergeId new_value)

merge

public void merge(java.util.Map<Address,View> views)

Invoked upon receiving a MERGE event from the MERGE layer. Starts the merge protocol. See description of protocol in DESIGN.

Parameters:

views - A List of different views detected by the merge protocol, keyed by sender

handleMergeRequest

public void handleMergeRequest(Address sender,
                               MergeId merge_id,
                               java.util.Collection<? extends Address> mbrs)

Get the view and digest and send back both (MergeData) in the form of a MERGE_RSP to the sender. If a merge is already in progress, send back a MergeData with the merge_rejected field set to true.

Parameters:

sender - The address of the merge leader

merge_id - The merge ID

mbrs - The set of members from which we expect responses. Guaranteed to be non-null

handleMergeResponse

public void handleMergeResponse(MergeData data,
                                MergeId merge_id)

handleMergeView

public void handleMergeView(MergeData data,
                            MergeId merge_id)

If merge_id is not equal to this.merge_id then discard. Else cast the view/digest to all members of this group.

handleMergeCancelled

public void handleMergeCancelled(MergeId merge_id)

handleDigestResponse

public void handleDigestResponse(Address sender,
                                 Digest digest)

sanitizeViews

public static void sanitizeViews(java.util.Map<Address,View> map)

Removes all members from a given view which don't have us in their view (https://jira.jboss.org/browse/JGRP-1061). Example:

 A: AB
 B: AB
 C: ABC
 

becomes

 A: AB
 B: AB
 C: C // A and B don't have C in their views
 

Parameters:

map - A map of members and their associated views

determineMergeLeader

protected Address determineMergeLeader(java.util.Map<Address,View> views)

Returns the address of the merge leader

determineMergeCoords

protected static java.util.Map<Address,java.util.Collection<Address>> determineMergeCoords(java.util.Map<Address,View> views)

Needs to return a map of all subview coordinators and their views (as a collection of members). The merge policy is defined in https://issues.jboss.org/browse/JGRP-1910

_handleMergeRequest

protected void _handleMergeRequest(Address sender,
                                   MergeId merge_id,
                                   java.util.Collection<? extends Address> mbrs)
                            throws java.lang.Exception

Throws:

java.lang.Exception

sendMergeResponse

protected void sendMergeResponse(Address sender,
                                 View view,
                                 Digest digest,
                                 MergeId merge_id)

Send back a response containing view and digest to sender

sendMergeView

protected void sendMergeView(java.util.Collection<Address> coords,
                             MergeData combined_merge_data,
                             MergeId merge_id)

Sends the new view and digest to all subgroup coordinors in coords. Each coord will in turn

1. broadcast the new view and digest to all the members of its subgroup (MergeView)
2. on reception of the view, if it is a MergeView, each member will set the digest and install the new view

sendMergeRejectedResponse

protected void sendMergeRejectedResponse(Address sender,
                                         MergeId merge_id)

sendMergeCancelledMessage

protected void sendMergeCancelledMessage(java.util.Collection<Address> coords,
                                         MergeId merge_id)

fetchDigestsFromAllMembersInSubPartition

protected Digest fetchDigestsFromAllMembersInSubPartition(View view,
                                                          MergeId merge_id)

Multicasts a GET_DIGEST_REQ to all members of this sub partition and waits for all responses (GET_DIGEST_RSP) or N ms.

fixDigests

protected void fixDigests()

Fetches the digests from all members and installs them again. Used only for diagnosis and support; don't use this otherwise !

stop

protected void stop()

cancelMerge

protected void cancelMerge(MergeId id)

forceCancelMerge

protected void forceCancelMerge()

startMergeKiller

protected void startMergeKiller()

stopMergeKiller

protected void stopMergeKiller()