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* Copyright 2000 - 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.cache.buddyreplication;
import org.jboss.cache.CacheException;
import org.jboss.cache.Fqn;
import org.jgroups.Address;
import java.util.ArrayList;
import java.util.List;
/**
* Knows how to transform between fqn and buddy-formated fqns.
*
* @author Mircea.Markus@jboss.com
* @since 2.2
*/
public class BuddyFqnTransformer
{
public static final String BUDDY_BACKUP_SUBTREE = BuddyManager.BUDDY_BACKUP_SUBTREE;
public static final Fqn BUDDY_BACKUP_SUBTREE_FQN = BuddyManager.BUDDY_BACKUP_SUBTREE_FQN;
/**
* Utility method that retrieves a buddy backup Fqn given the actual Fqn of some data and the data owner's Address.
*
* @param dataOwnerAddress the JGroups {@link org.jgroups.Address} of the data owner
* @param origFqn the original Fqn
* @return a backup Fqn
*/
public Fqn getBackupFqn(Address dataOwnerAddress, Fqn origFqn)
{
return getBackupFqn(getGroupNameFromAddress(dataOwnerAddress), origFqn);
}
/**
* Utility method that retrieves a buddy backup Fqn given the actual Fqn of some data and the buddy group name.
*
* @param buddyGroupName the buddy group name
* @param origFqn the original Fqn
* @return a backup Fqn
*/
public Fqn getBackupFqn(String buddyGroupName, Fqn origFqn)
{
if (isBackupFqn(origFqn))
throw new CacheException("Cannot make a backup Fqn from a backup Fqn! Attempting to create a backup of " + origFqn);
List<Object> elements = new ArrayList<Object>(origFqn.size() + 2);
elements.add(BuddyManager.BUDDY_BACKUP_SUBTREE);
elements.add(buddyGroupName);
elements.addAll(origFqn.peekElements());
return Fqn.fromList(elements, true);
}
/**
* Utility method that retrieves a buddy backup Fqn given the actual Fqn of some data and the backup subtree for the
* buddy group in question
*
* @param buddyGroupRoot the subtree under which data for a particular buddy is backed up
* @param origFqn the original Fqn
* @return a backup Fqn
*/
public Fqn getBackupFqn(Fqn buddyGroupRoot, Fqn origFqn)
{
if (isBackupFqn(origFqn))
throw new CacheException("Cannot make a backup Fqn from a backup Fqn! Attempting to create a backup of " + origFqn);
List<Object> elements = new ArrayList<Object>(origFqn.size() + 2);
elements.add(BuddyManager.BUDDY_BACKUP_SUBTREE);
elements.add(buddyGroupRoot.get(1));
elements.addAll(origFqn.peekElements());
return Fqn.fromList(elements, true);
}
public boolean isBackupFqn(Fqn name)
{
return name != null && name.hasElement(BuddyManager.BUDDY_BACKUP_SUBTREE);
}
public Fqn getActualFqn(Fqn fqn)
{
if (!isBackupFqn(fqn)) return fqn;
if (fqn.equals(BUDDY_BACKUP_SUBTREE_FQN)) return Fqn.ROOT;
// remove the first 2 (or 3 in the case of a dead backup region) elements
return fqn.getSubFqn(isDeadBackupFqn(fqn) ? 3 : 2, fqn.size());
}
/**
* Tests whether a given Fqn belongs to a dead backup region.
*
* @param name fqn to test
* @return true if the fqn is a part of a dead backup region; false otherwise.
*/
public boolean isDeadBackupFqn(Fqn name)
{
if (name == null || name.size() < 2) return false;
Object elem1 = name.get(1);
if (elem1 instanceof String)
{
String strElem1 = (String) elem1;
return name.hasElement(BuddyManager.BUDDY_BACKUP_SUBTREE) && strElem1.endsWith(":DEAD");
}
else
{
return false;
}
}
/**
* @param dataOwner owner of a data set
* @return a backup root for a given data owner
*/
public Fqn getBackupRoot(Address dataOwner)
{
return Fqn.fromRelativeElements(BUDDY_BACKUP_SUBTREE_FQN, getGroupNameFromAddress(dataOwner));
}
/**
* Returns the backup root of a dead data owner
*
* @param dataOwner owner of data
* @return Fqn of dead data owner's root
*/
public Fqn getDeadBackupRoot(Address dataOwner)
{
return Fqn.fromRelativeElements(BUDDY_BACKUP_SUBTREE_FQN, getGroupNameFromAddress(dataOwner) + ":DEAD");
}
public boolean isDeadBackupRoot(Fqn f)
{
return f.isDirectChildOf(BUDDY_BACKUP_SUBTREE_FQN) && f.getLastElementAsString().endsWith(":DEAD");
}
public String getGroupNameFromAddress(Address address)
{
return address.toString().replace(':', '_');
}
/**
* Returns the buddy backp root portion of a given Fqn, provided it is a backup Fqn. If it is not a backup Fqn, Fqn.ROOT is returned.
*
* @param fqn fqn
* @return a backup root from an Fqn
*/
public Fqn getBackupRootFromFqn(Fqn fqn)
{
if (isBackupFqn(fqn) && fqn.size() > 1)
{
return fqn.getSubFqn(0, isDeadBackupFqn(fqn) ? 3 : 2);
}
else
{
return Fqn.root();
}
}
}