package org.jgroups;
import org.jgroups.annotations.Immutable;
import org.jgroups.util.Util;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.function.Supplier;
/**
* A view that is sent as a result of a cluster merge. Whenever a group splits into subgroups, e.g., due to
* a network partition, and later the subgroups merge back together, a MergeView instead of a View
* will be received by the application. The MergeView class is a subclass of View and contains as
* additional instance variable: the list of views that were merged. For example, if the group
* denoted by view V1:(p,q,r,s,t) splits into subgroups V2:(p,q,r) and V2:(s,t), the merged view
* might be V3:(p,q,r,s,t). In this case the MergeView would contain a list of 2 views: V2:(p,q,r)
* and V2:(s,t).
*
* @since 2.0
* @author Bela Ban
*/
@Immutable
public class MergeView extends View {
protected View[] subgroups; // subgroups that merged into this single view (a list of Views)
public MergeView() { // Used by externalization
}
/**
* Creates a new merge view
*
* @param view_id The view id of this view (can not be null)
* @param members Contains a list of all the members in the view, can be empty but not null.
* @param subgroups A list of Views representing the former subgroups
*/
public MergeView(ViewId view_id, List<Address> members, List<View> subgroups) {
super(view_id, members);
this.subgroups=listToArray(subgroups);
}
public MergeView(ViewId view_id, Address[] members, List<View> subgroups) {
super(view_id, members);
this.subgroups=listToArray(subgroups);
}
/**
* Creates a new view
*
* @param creator The creator of this view (can not be null)
* @param id The lamport timestamp of this view
* @param members Contains a list of all the members in the view, can be empty but not null.
* @param subgroups A list of Views representing the former subgroups
*/
public MergeView(Address creator, long id, List<Address> members, List<View> subgroups) {
super(creator, id, members);
this.subgroups=listToArray(subgroups);
}
public Supplier<? extends MergeView> create() {
return MergeView::new;
}
public List<View> getSubgroups() {
return Collections.unmodifiableList(Arrays.asList(subgroups));
}
public MergeView copy() {
return this;
}
public boolean deepEquals(View other) {
if(!super.deepEquals(other)) return false;
if(!(other instanceof MergeView))
return true;
MergeView other_view=(MergeView)other;
if(subgroups == null && other_view.subgroups == null) return true;
if(subgroups.length != other_view.subgroups.length) return false;
for(int i=0; i < subgroups.length; i++) {
View my_view=subgroups[i], oth_view=other_view.subgroups[i];
if(!my_view.deepEquals(oth_view))
return false;
}
return true;
}
public String toString() {
StringBuilder sb=new StringBuilder();
sb.append("MergeView::").append(super.toString());
if(subgroups != null && subgroups.length > 0) {
sb.append(", ").append(subgroups.length).append(" subgroups: ");
sb.append(Util.printListWithDelimiter(subgroups, ", ", Util.MAX_LIST_PRINT_SIZE));
}
return sb.toString();
}
public void writeTo(DataOutput out) throws Exception {
super.writeTo(out);
// write subgroups
int len=subgroups != null? subgroups.length : 0;
out.writeShort(len);
if(len == 0)
return;
for(View v: subgroups) {
int index=get(v.getCreator());
out.writeShort(index);
// if we don't find the member, write the addres (https://issues.jboss.org/browse/JGRP-1707)
if(index < 0)
Util.writeAddress(v.getCreator(), out);
out.writeLong(v.getViewId().getId());
int num_mbrs=v.size();
out.writeShort(num_mbrs);
for(Address mbr: v) {
index=get(mbr);
out.writeShort(index);
if(index < 0)
Util.writeAddress(mbr, out);
}
}
}
public void readFrom(DataInput in) throws Exception {
super.readFrom(in);
short len=in.readShort();
if(len > 0) {
subgroups=new View[len];
for(int i=0; i < len; i++) {
int index=in.readShort();
Address creator=index >= 0 ? get(index) : Util.readAddress(in);
long id=in.readLong();
Address[] mbrs=new Address[in.readShort()];
for(int j=0; j < mbrs.length; j++) {
index=in.readShort();
mbrs[j]=index >= 0? get(index) : Util.readAddress(in);
}
try {
View view=View.create(creator, id, mbrs);
subgroups[i]=view;
}
catch(Throwable t) {
}
}
}
}
public int serializedSize() {
int retval=super.serializedSize();
retval+=Global.SHORT_SIZE; // for size of subgroups vector
if(subgroups == null)
return retval;
for(View v: subgroups) {
retval+=Global.SHORT_SIZE + Global.LONG_SIZE // creator and ID (ViewId)
+ Global.SHORT_SIZE; // number of members in the subview
Address creator=v.getCreator();
if(get(creator) < 0)
retval+=Util.size(creator);
retval+=v.size() * Global.SHORT_SIZE; // a short (index) for each member
for(Address sub_mbr: v) {
int index=get(sub_mbr);
if(index < 0)
retval+=Util.size(sub_mbr);
}
}
return retval;
}
protected static View[] listToArray(List<View> list) {
if(list == null)
return null;
View[] retval=new View[list.size()];
int index=0;
for(View view: list)
retval[index++]=view;
return retval;
}
protected int get(Address member) {
if(member == null)
return -1;
for(int i=0; i < members.length; i++)
if(member.equals(members[i]))
return i;
return -1;
}
protected Address get(int index) {
return members != null && index >= 0 && index < members.length? members[index] : null;
}
}