package org.jgroups.protocols.pbcast;
import org.jgroups.Address;
import org.jgroups.View;
import org.jgroups.ViewId;
import org.jgroups.util.ArrayIterator;
import org.jgroups.util.Util;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.Arrays;
import java.util.Iterator;
/**
* Subclass of {@link org.jgroups.View} with a null members field. Adds an array for left members and one for joined
* members compared to the previous view. A recipient receiving a DeltaView can construct a new view by grabbing the
* view corresponding to {@link #view_id}, removing the left members and adding the new members.<p/>
* This class is only used with VIEW messages in GMS to install new views (not merge views). When a VIEW
* message is received, the DeltaView is read from the {@link org.jgroups.protocols.pbcast.GMS.GmsHeader}, a View is
* constructured and the header discarded. Therefore, the lifetime of a DeltaView is short: it is created and set in
* a GmsHeader, the header is then marshalled. On the receiving side, the DeltaView is created from the stream, a View
* is created and the DeltaView discarded again.<p/>
* Instances of this class are created by {@link CoordGmsImpl#handleMembershipChange(java.util.Collection)}.<p/>
* JIRA issue: https://issues.jboss.org/browse/JGRP-1354
* @author Bela Ban
* @since 3.4
*/
public class DeltaView extends View {
/** The fields left_members and new_members refer to the view corresponding to ref_view_id */
protected ViewId ref_view_id;
/** Members which left the view corresponding to ref_view_id */
protected Address[] left_members;
/** Members which joined the view corresponding to ref_view_id */
protected Address[] new_members;
public DeltaView() {
}
public DeltaView(ViewId view_id, ViewId ref_view_id, Address[] left_members, Address[] new_members) {
this.view_id=view_id;
this.ref_view_id=ref_view_id;
this.left_members=left_members;
this.new_members=new_members;
if(view_id == null) throw new IllegalArgumentException("view_id cannot be null");
if(ref_view_id == null) throw new IllegalArgumentException("ref_view_id cannot be null");
}
public ViewId getRefViewId() {return ref_view_id;}
public Address[] getLeftMembers() {return left_members;}
public Address[] getNewMembers() {return new_members;}
public int serializedSize() {
int retval=view_id.serializedSize() + ref_view_id.serializedSize();
retval+=Util.size(left_members);
retval+=Util.size(new_members);
return retval;
}
public void writeTo(DataOutput out) throws Exception {
view_id.writeTo(out);
ref_view_id.writeTo(out);
Util.writeAddresses(left_members, out);
Util.writeAddresses(new_members, out);
}
public void readFrom(DataInput in) throws Exception {
view_id=new ViewId();
view_id.readFrom(in);
ref_view_id=new ViewId();
ref_view_id.readFrom(in);
left_members=Util.readAddresses(in);
new_members=Util.readAddresses(in);
}
public Iterator<Address> iterator() {
Address[] combined=new Address[left_members.length + new_members.length];
int left_len=left_members.length;
System.arraycopy(left_members, 0, combined, 0, left_len);
System.arraycopy(new_members, 0, combined, left_len, new_members.length);
return new ArrayIterator<Address>(combined);
}
public String toString() {
StringBuilder sb=new StringBuilder(super.toString()).append(", ref-view=").append(ref_view_id);
if(left_members != null && left_members.length > 0)
sb.append(", left=").append(Arrays.toString(left_members));
if(new_members != null && new_members.length > 0)
sb.append(", joined=").append(Arrays.toString(new_members));
return sb.toString();
}
}