/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
*
* Copyright 2006-2010 Sun Microsystems, Inc.
* Portions Copyright 2011-2013 ForgeRock AS
*/
package org.opends.server.replication.common;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.zip.DataFormatException;
import org.opends.server.protocols.asn1.ASN1Writer;
import org.opends.server.replication.protocol.ProtocolVersion;
import org.opends.server.types.ByteString;
/**
* ServerState class.
* This object is used to store the last update seen on this server
* from each server.
* It is exchanged with the replication servers at connection establishment
* time.
*/
public class ServerState implements Iterable<Integer>
{
private final HashMap<Integer, ChangeNumber> list;
private volatile boolean saved = true;
/**
* Creates a new empty ServerState.
*/
public ServerState()
{
list = new HashMap<Integer, ChangeNumber>();
}
/**
* Empty the ServerState.
* After this call the Server State will be in the same state
* as if it was just created.
*/
public void clear()
{
synchronized (list)
{
list.clear();
}
}
/**
* Creates a new ServerState object from its encoded form.
*
* @param in The byte array containing the encoded ServerState form.
* @param pos The position in the byte array where the encoded ServerState
* starts.
* @param endpos The position in the byte array where the encoded ServerState
* ends.
* @throws DataFormatException If the encoded form was not correct.
*/
public ServerState(byte[] in, int pos, int endpos)
throws DataFormatException
{
try
{
list = new HashMap<Integer, ChangeNumber>();
while (endpos > pos)
{
/*
* read the ServerId
*/
int length = getNextLength(in, pos);
String serverIdString = new String(in, pos, length, "UTF-8");
int serverId = Integer.valueOf(serverIdString);
pos += length +1;
/*
* read the ChangeNumber
*/
length = getNextLength(in, pos);
String cnString = new String(in, pos, length, "UTF-8");
ChangeNumber cn = new ChangeNumber(cnString);
pos += length +1;
/*
* Add the serverid
*/
list.put(serverId, cn);
}
} catch (UnsupportedEncodingException e)
{
throw new DataFormatException("UTF-8 is not supported by this jvm.");
}
}
/**
* Get the length of the next String encoded in the in byte array.
* This method is used to cut the different parts (server ids, change number)
* of a server state.
*
* @param in the byte array where to calculate the string.
* @param pos the position where to start from in the byte array.
* @return the length of the next string.
* @throws DataFormatException If the byte array does not end with null.
*/
private int getNextLength(byte[] in, int pos) throws DataFormatException
{
int offset = pos;
int length = 0;
while (in[offset++] != 0)
{
if (offset >= in.length)
throw new DataFormatException("byte[] is not a valid server state");
length++;
}
return length;
}
/**
* Update the Server State with a ChangeNumber.
*
* @param changeNumber The committed ChangeNumber.
*
* @return a boolean indicating if the update was meaningful.
*/
public boolean update(ChangeNumber changeNumber)
{
if (changeNumber == null)
return false;
saved = false;
synchronized(list)
{
int id = changeNumber.getServerId();
ChangeNumber oldCN = list.get(id);
if (oldCN == null || changeNumber.newer(oldCN))
{
list.put(id,changeNumber);
return true;
}
else
{
return false;
}
}
}
/**
* Update the Server State with a Server State. Every change number of this
* object is updated with the change number of the passed server state if
* it is newer.
*
* @param serverState the server state to use for the update.
*
* @return a boolean indicating if the update was meaningful.
*/
public boolean update(ServerState serverState)
{
if (serverState == null)
return false;
boolean updated = false;
for (ChangeNumber cn : serverState.list.values())
{
if (update(cn))
{
updated = true;
}
}
return updated;
}
/**
* Replace the Server State with another ServerState.
*
* @param serverState The ServerState.
*
* @return a boolean indicating if the update was meaningful.
*/
public boolean reload(ServerState serverState) {
if (serverState == null) {
return false;
}
boolean result = false;
synchronized (list)
{
clear();
for (Integer id : serverState) {
ChangeNumber maxChangeNumber = serverState.getMaxChangeNumber(id);
if (this.update(maxChangeNumber)) {
result = true;
}
}
}
return (result);
}
/**
* return a Set of String usable as a textual representation of
* a Server state.
* format : time seqnum id
*
* example :
* 1 00000109e4666da600220001
* 2 00000109e44567a600220002
*
* @return the representation of the Server state
*/
public Set<String> toStringSet()
{
HashSet<String> set = new HashSet<String>();
synchronized (list)
{
for (int key : list.keySet())
{
ChangeNumber change = list.get(key);
Date date = new Date(change.getTime());
set.add(change.toString() + " " + date.toString() + " "
+ change.getTime());
}
}
return set;
}
/**
* Return an ArrayList of ANS1OctetString encoding the ChangeNumbers
* contained in the ServerState.
* @return an ArrayList of ANS1OctetString encoding the ChangeNumbers
* contained in the ServerState.
*/
public ArrayList<ByteString> toASN1ArrayList()
{
ArrayList<ByteString> values = new ArrayList<ByteString>(0);
synchronized (list)
{
for (int id : list.keySet())
{
ByteString value = ByteString.valueOf(list.get(id).toString());
values.add(value);
}
}
return values;
}
/**
* Encodes this server state to the provided ASN1 writer.
*
* @param writer
* The ASN1 writer.
* @param protocolVersion
* The replication protocol version.
* @throws IOException
* If an error occurred during encoding.
*/
public void writeTo(ASN1Writer writer, short protocolVersion)
throws IOException
{
synchronized (list)
{
if (protocolVersion >= ProtocolVersion.REPLICATION_PROTOCOL_V7)
{
for (ChangeNumber cn : list.values())
{
writer.writeOctetString(cn.toByteString());
}
}
else
{
for (ChangeNumber cn : list.values())
{
writer.writeOctetString(cn.toString());
}
}
}
}
/**
* Return the text representation of ServerState.
* @return the text representation of ServerState
*/
public String toString()
{
StringBuilder buffer = new StringBuilder();
synchronized (list)
{
for (int key : list.keySet())
{
ChangeNumber change = list.get(key);
buffer.append(change.toString());
buffer.append(" ");
}
if (!list.isEmpty())
buffer.deleteCharAt(buffer.length()-1);
}
return buffer.toString();
}
/**
* Get the largest ChangeNumber seen for a given LDAP server ID.
*
* @param serverId2 : the server ID
* @return the largest ChangeNumber seen
*/
public ChangeNumber getMaxChangeNumber(int serverId2)
{
return list.get(serverId2);
}
/**
* Get the largest ChangeNumber.
* @return the largest ChangeNumber
*/
public ChangeNumber getMaxChangeNumber()
{
ChangeNumber maxCN = null;
synchronized (list)
{
for (int id : list.keySet())
{
ChangeNumber tmpMax = list.get(id);
if ((maxCN==null) || (tmpMax.newer(maxCN)))
maxCN = tmpMax;
}
}
return maxCN;
}
/**
* Add the tail into resultByteArray at position pos.
*/
private int addByteArray(byte[] tail, byte[] resultByteArray, int pos)
{
for (int i=0; i<tail.length; i++,pos++)
{
resultByteArray[pos] = tail[i];
}
resultByteArray[pos++] = 0;
return pos;
}
/**
* Encode this ServerState object and return its byte array representation.
*
* @return a byte array with an encoded representation of this object.
* @throws UnsupportedEncodingException if UTF8 is not supported by the JVM.
*/
public byte[] getBytes() throws UnsupportedEncodingException
{
synchronized (list)
{
int length = 0;
List<String> idList = new ArrayList<String>(list.size());
for (int id : list.keySet())
{
String temp = String.valueOf(id);
idList.add(temp);
length += temp.length() + 1;
}
List<String> cnList = new ArrayList<String>(list.size());
for (ChangeNumber cn : list.values())
{
String temp = cn.toString();
cnList.add(temp);
length += temp.length() + 1;
}
byte[] result = new byte[length];
int pos = 0;
for (int i=0; i< list.size(); i++)
{
String str = idList.get(i);
pos = addByteArray(str.getBytes("UTF-8"), result, pos);
str = cnList.get(i);
pos = addByteArray(str.getBytes("UTF-8"), result, pos);
}
return result;
}
}
/**
* {@inheritDoc}
*/
public Iterator<Integer> iterator()
{
return list.keySet().iterator();
}
/**
* Check that all the ChangeNumbers in the covered serverState are also in
* this serverState.
*
* @param covered The ServerState that needs to be checked.
* @return A boolean indicating if this ServerState covers the ServerState
* given in parameter.
*/
public boolean cover(ServerState covered)
{
for (ChangeNumber coveredChange : covered.list.values())
{
ChangeNumber change = this.list.get(coveredChange.getServerId());
if ((change == null) || (change.older(coveredChange)))
{
return false;
}
}
return true;
}
/**
* Checks that the ChangeNumber given as a parameter is in this ServerState.
*
* @param covered The ChangeNumber that should be checked.
* @return A boolean indicating if this ServerState contains the ChangeNumber
* given in parameter.
*/
public boolean cover(ChangeNumber covered)
{
ChangeNumber change = this.list.get(covered.getServerId());
return !((change == null) || (change.older(covered)));
}
/**
* Tests if the state is empty.
*
* @return True if the state is empty.
*/
public boolean isEmpty()
{
return list.isEmpty();
}
/**
* Make a duplicate of this state.
* @return The duplicate of this state.
*/
public ServerState duplicate()
{
ServerState newState = new ServerState();
synchronized (list)
{
for (Integer key : list.keySet())
{
ChangeNumber change = list.get(key);
Integer id = change.getServerId();
newState.list.put(id,change);
}
}
return newState;
}
/**
* Computes the number of changes a first server state has in advance
* compared to a second server state.
* @param ss1 The server state supposed to be newer than the second one
* @param ss2 The server state supposed to be older than the first one
* @return The difference of changes (sum of the differences for each server
* id changes). 0 If no gap between 2 states.
* @throws IllegalArgumentException If one of the passed state is null
*/
public static int diffChanges(ServerState ss1, ServerState ss2)
throws IllegalArgumentException
{
if ( (ss1 == null) || (ss2 == null) )
throw new IllegalArgumentException("Null server state(s)");
int diff = 0;
for (Integer serverId : ss1.list.keySet())
{
ChangeNumber cn1 = ss1.list.get(serverId);
if (cn1 != null)
{
ChangeNumber cn2 = ss2.list.get(serverId);
if (cn2 != null)
{
diff += ChangeNumber.diffSeqNum(cn1, cn2);
} else {
// ss2 does not have a change for this server id but ss1, so the
// server holding ss1 has every changes represented in cn1 in advance
// compared to server holding ss2, add this amount
diff += cn1.getSeqnum();
}
}
}
return diff;
}
/**
* Set the saved status of this ServerState.
*
* @param b A boolean indicating if the State has been safely stored.
*/
public void setSaved(boolean b)
{
saved = b;
}
/**
* Get the saved status of this ServerState.
*
* @return The saved status of this ServerState.
*/
public boolean isSaved()
{
return saved;
}
/**
* Build a copy of the ServerState with only ChangeNumbers older than
* a specific ChangeNumber. This is used when building the initial
* Cookie in the External Changelog, to cope with purged changes.
* @param cn The ChangeNumber to compare the ServerState with
* @return a copy of the ServerState which only contains the ChangeNumbers
* older than cn.
*/
public ServerState duplicateOnlyOlderThan(ChangeNumber cn)
{
ServerState newState = new ServerState();
synchronized (list)
{
for (Integer key : list.keySet())
{
ChangeNumber change = list.get(key);
Integer id = change.getServerId();
if (change.older(cn))
{
newState.list.put(id,change);
}
}
}
return newState;
}
}