How to use

Digest$Entry

in

org.jgroups.util

public Entry next() {
  if(index >= capacity())
    throw new NoSuchElementException("index=" + index + ", capacity=" + capacity());
  Address mbr=members != null? members[index] : null;
  long hd=seqnos != null? seqnos[index*2] : 0, hr=seqnos != null? seqnos[index*2+1] : 0;
  Entry entry=new Entry(mbr, hd, hr);
  index++;
  return entry;
}

Address member=entry.getMember();
long[] my_entry=my_digest.get(member);
if(my_entry == null)
  continue;
long their_high=entry.getHighest();

Address member=entry.getMember();
if(member == null)
  continue;
long highest_delivered_seqno=entry.getHighestDeliveredSeqno();

public MutableDigest set(Digest digest) {
  if(digest == null)
    return this;
  for(Entry entry: digest)
    set(entry.getMember(), entry.getHighestDeliveredSeqno(), entry.getHighestReceivedSeqno());
  return this;
}

public Entry next() {
  if(index >= capacity())
    throw new NoSuchElementException("index=" + index + ", capacity=" + capacity());
  Address mbr=members != null? members[index] : null;
  long hd=seqnos != null? seqnos[index*2] : 0, hr=seqnos != null? seqnos[index*2+1] : 0;
  Entry entry=new Entry(mbr, hd, hr);
  index++;
  return entry;
}

public Entry(long low_seqno, long highest_delivered_seqno) {
  this.low_seqno=low_seqno;
  this.highest_delivered_seqno=highest_delivered_seqno;
  check();
}

public void setHighestDeliveredAndSeenSeqnos(Address sender, long low_seqno, long highest_delivered_seqno, long highest_received_seqno) {
  Entry entry=senders.get(sender);
  if(entry != null) {
    checkSealed();
    Entry new_entry=new Entry(low_seqno, highest_delivered_seqno, highest_received_seqno);
    senders.put(sender, new_entry);
  }
}

/**
 * Adds a digest to this digest. For each sender in the other digest, the merge() method will be called.
 */
public MutableDigest merge(Digest digest) {
  if(digest == null)
    return this;
  for(Entry entry: digest)
    merge(entry.getMember(), entry.getHighestDeliveredSeqno(), entry.getHighestReceivedSeqno());
  return this;
}

public void add(Address sender, long low_seqno, long highest_delivered_seqno, long highest_received_seqno) {
  checkSealed();
  add(sender, new Digest.Entry(low_seqno, highest_delivered_seqno, highest_received_seqno));
}

public Digest(Address sender, long low, long highest_delivered, long highest_received) {
  senders=createSenders(1);
  senders.put(sender, new Entry(low, highest_delivered, highest_received));
}

public void add(Digest digest) {
  if(digest != null) {
    checkSealed();
    Map.Entry<Address,Entry> entry;
    Address key;
    Entry val;
    for(Iterator<Map.Entry<Address,Entry>> it=digest.senders.entrySet().iterator(); it.hasNext();) {
      entry=it.next();
      key=entry.getKey();
      val=entry.getValue();
      add(key, val.getLow(), val.getHighestDeliveredSeqno(), val.getHighestReceivedSeqno());
    }
  }
}

/**
 * Returns true if all senders of the current digest have their seqnos >= the ones from other
 */
protected static boolean isGreaterThanOrEqual(Digest first, Digest other) {
  if(other == null)
    return true;
  for(Digest.Entry entry: first) {
    Address sender=entry.getMember();
    long[] their_entry=other.get(sender);
    if(their_entry == null)
      continue;
    long my_highest=entry.getHighest();
    long their_highest=Math.max(their_entry[0],their_entry[1]);
    if(my_highest < their_highest)
      return false;
  }
  return true;
}

/**
 * Adds a digest to this digest. This digest must have enough space to add the other digest; otherwise an error
 * message will be written. For each sender in the other digest, the merge() method will be called.
 */
public void merge(Digest digest) {
  if(digest == null) {
    if(log.isErrorEnabled()) log.error("digest to be merged with is null");
    return;
  }
  checkSealed();
  Map.Entry<Address,Entry> entry;
  Address sender;
  Entry val;
  for(Iterator<Map.Entry<Address,Entry>> it=digest.senders.entrySet().iterator(); it.hasNext();) {
    entry=it.next();
    sender=entry.getKey();
    val=entry.getValue();
    if(val != null) {
      merge(sender, val.getLow(), val.getHighestDeliveredSeqno(), val.getHighestReceivedSeqno());
    }
  }
}

/**
 * Increments the sender's high_seqno by 1.
 */
public void incrementHighestDeliveredSeqno(Address sender) {
  Entry entry=senders.get(sender);
  if(entry == null)
    return;
  checkSealed();
  Entry new_entry=new Entry(entry.getLow(), entry.getHighestDeliveredSeqno() +1, entry.getHighestReceivedSeqno());
  senders.put(sender, new_entry);
}

/**
 * Similar to add(), but if the sender already exists, its seqnos will be modified (no new entry) as follows:
 * <ol>
 * <li>this.low_seqno=min(this.low_seqno, low_seqno)
 * <li>this.highest_delivered_seqno=max(this.highest_delivered_seqno, highest_delivered_seqno)
 * <li>this.highest_received_seqno=max(this.highest_received_seqno, highest_received_seqno)
 * </ol>
 * If the sender doesn not exist, a new entry will be added (provided there is enough space)
 */
public void merge(Address sender, long low_seqno, long highest_delivered_seqno, long highest_received_seqno) {
  if(sender == null) {
    if(log.isErrorEnabled()) log.error("sender == null");
    return;
  }
  checkSealed();
  Entry entry=senders.get(sender);
  if(entry == null) {
    add(sender, low_seqno, highest_delivered_seqno, highest_received_seqno);
  }
  else {
    Entry new_entry=new Entry(Math.min(entry.getLow(), low_seqno),
                 Math.max(entry.getHighestDeliveredSeqno(), highest_delivered_seqno),
                 Math.max(entry.getHighestReceivedSeqno(), highest_received_seqno));
    senders.put(sender, new_entry);
  }
}

public Entry(Entry other) {
  if(other != null) {
    low_seqno=other.low_seqno;
    highest_delivered_seqno=other.highest_delivered_seqno;
    highest_received_seqno=other.highest_received_seqno;
    check();
  }
}

/** Update my own digest from a digest received by somebody else. Returns whether the update was successful.
 *  Needs to be called with a lock on digest */
@GuardedBy("lock")
protected void updateLocalDigest(Digest d, Address sender) {
  StringBuilder sb=null;
  if(log.isTraceEnabled())
    sb=new StringBuilder().append(local_addr).append(": handling digest from ").append(sender).append(":\nmine:   ")
     .append(printDigest(digest)).append("\nother:  ").append(printDigest(d));
  for(Digest.Entry entry: d) {
    Address mbr=entry.getMember();
    long hd=entry.getHighestDeliveredSeqno(), hr=entry.getHighestReceivedSeqno();
    // compute the minimum of the highest seqnos deliverable (for garbage collection)
    long[] seqnos=digest.get(mbr);
    if(seqnos == null)
      continue;
    long my_hd=seqnos[0];
    long my_hr=seqnos[1]; // (for retransmission of last missing message)
    if(my_hd == -1) // -1 means the seqno hasn't been set yet
      my_hd=hd;
    long new_hd=Math.min(my_hd, hd);
    long new_hr=Math.max(my_hr, hr);
    digest.set(mbr, new_hd, new_hr);
  }
  if(sb != null) // implies log.isTraceEnabled() == true
    log.trace(sb.append("\nresult: ").append(printDigest(digest)).append("\n"));
}

public MutableDigest set(Digest digest) {
  if(digest == null)
    return this;
  for(Entry entry: digest)
    set(entry.getMember(), entry.getHighestDeliveredSeqno(), entry.getHighestReceivedSeqno());
  return this;
}

/**
 * Returns true if all senders of the current digest have their seqnos >= the ones from other
 * @param other
 * @return
 */
public boolean isGreaterThanOrEqual(Digest other) {
  if(other == null)
    return true;
  Map<Address,Entry> our_map=getSenders();
  Address sender;
  Entry my_entry, their_entry;
  long my_highest, their_highest;
  for(Map.Entry<Address,Entry> entry: our_map.entrySet()) {
    sender=entry.getKey();
    my_entry=entry.getValue();
    their_entry=other.get(sender);
    if(their_entry == null)
      continue;
    my_highest=my_entry.getHighest();
    their_highest=their_entry.getHighest();
    if(my_highest < their_highest)
      return false;
  }
  return true;
}

/**
 * Resets the seqnos for the sender at 'index' to 0. This happens when a member has left the group,
 * but it is still in the digest. Resetting its seqnos ensures that no-one will request a message
 * retransmission from the dead member.
 */
public void resetAt(Address sender) {
  Entry entry=senders.get(sender);
  if(entry != null)
    checkSealed();
    senders.put(sender, new Entry());
}