/*
* JBoss, Home of Professional Open Source
*
* Distributable under LGPL license.
* See terms of license at gnu.org.
*/
package org.jboss.cache;
import org.apache.commons.logging.LogFactory;
import org.jboss.cache.lock.IdentityLock;
import org.jboss.cache.optimistic.DataVersion;
import org.jboss.cache.optimistic.DefaultDataVersion;
import java.util.Map;
/**
* VersionedNode extends the {@link org.jboss.cache.UnversionedNode} by adding a {@link org.jboss.cache.optimistic.DataVersion} property.
* <p/>
* Unlike {@link org.jboss.cache.UnversionedNode}, this node supports {@link #getVersion} and {@link #setVersion(org.jboss.cache.optimistic.DataVersion)}
* defined in {@link org.jboss.cache.NodeSPI}
* <p/>
* Typically used when the cache mode configured is {@link org.jboss.cache.config.Configuration.NodeLockingScheme#OPTIMISTIC}
*
* @author <a href="mailto:manik@jboss.org">Manik Surtani (manik@jboss.org)</a>
* @since 2.0.0
*/
public class VersionedNode<K, V> extends UnversionedNode<K, V>
{
private static final String DATA_VERSION_INTERNAL_KEY = "_JBOSS_INTERNAL_OPTIMISTIC_DATA_VERSION";
private DataVersion version; // make sure this is NOT initialized to anything, even a null! Since the UnversionedNode constructor may set this value based on a data version passed along in the data map.
/**
* Although this object has a reference to the CacheImpl, the optimistic
* node is actually disconnected from the CacheImpl itself.
* The parent could be looked up from the TransactionWorkspace.
*/
private NodeSPI<K, V> parent;
protected VersionedNode(Fqn fqn, NodeSPI<K, V> parent, Map<K, V> data, CacheSPI<K, V> cache)
{
super(fqn.getLastElement(), fqn, data, false, cache);
if (version == null) version = DefaultDataVersion.ZERO;
if (parent == null && !fqn.isRoot()) throw new NullPointerException("parent");
this.parent = parent;
log = LogFactory.getLog(VersionedNode.class);
}
/**
* Returns the version id of this node.
*
* @return the version
*/
@Override
public DataVersion getVersion()
{
return version;
}
/**
* Returns the parent.
*/
@Override
public NodeSPI<K, V> getParent()
{
return parent;
}
/**
* Sets the version id of this node.
*
* @param version
*/
@Override
public void setVersion(DataVersion version)
{
this.version = version;
}
/**
* Optimistically locked nodes (VersionedNodes) will always use repeatable read.
*/
@Override
protected synchronized void initLock()
{
if (lock == null) lock = new IdentityLock(lockStrategyFactory, delegate);
}
@Override
public Map getInternalState(boolean onlyInternalState)
{
Map state = super.getInternalState(onlyInternalState);
state.put(DATA_VERSION_INTERNAL_KEY, version);
return state;
}
@Override
public void setInternalState(Map state)
{
if (state != null)
{
DataVersion dv = (DataVersion) state.remove(DATA_VERSION_INTERNAL_KEY);
if (dv != null) version = dv;
}
super.setInternalState(state);
}
}