org.hibernate.cache.jbc.util.DataVersionAdapter Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2007, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program 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 distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.cache.jbc.util;
import java.io.IOException;
import java.util.Comparator;
import org.hibernate.cache.jbc.entity.TransactionalAccess;
import org.hibernate.util.CalendarComparator;
import org.hibernate.util.ComparableComparator;
import org.jboss.cache.optimistic.DataVersion;
import org.jboss.cache.optimistic.DefaultDataVersion;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A DataVersionAdapter.
*
* @author Brian Stansberry
* @version $Revision: 1 $
*/
public class DataVersionAdapter implements DataVersion {
private static final Logger log = LoggerFactory.getLogger(TransactionalAccess.class);
private static final long serialVersionUID = 5564692336076405571L;
private final Object currentVersion;
private final Object previousVersion;
/**
* Comparator does not extend Serializable and the std impls don't either,
* so we make the field transient to allow special handling
*/
private transient Comparator versionComparator;
private final String sourceIdentifer;
public DataVersionAdapter(Object currentVersion, Object previousVersion, Comparator versionComparator,
String sourceIdentifer) {
this.currentVersion = currentVersion;
this.previousVersion = previousVersion;
this.versionComparator = versionComparator;
this.sourceIdentifer = sourceIdentifer;
log.trace("created " + this);
}
/**
* newerThan() call is dispatched against the DataVersion currently
* associated with the node; the passed dataVersion param is the DataVersion
* associated with the data we are trying to put into the node. we are
* expected to return true in the case where we (the current node
* DataVersion) are newer that then incoming value. Returning true here
* essentially means that a optimistic lock failure has occured (because
* conversely, the value we are trying to put into the node is "older than"
* the value already there...)
*/
public boolean newerThan(DataVersion dataVersion) {
log.trace("checking [" + this + "] against [" + dataVersion + "]");
if (dataVersion instanceof CircumventChecksDataVersion) {
log.trace("skipping lock checks...");
return false;
} else if (dataVersion instanceof NonLockingDataVersion) {
// can happen because of the multiple ways Cache.remove()
// can be invoked :(
log.trace("skipping lock checks...");
return false;
} else if (dataVersion instanceof DefaultDataVersion) {
// JBC put a version in the node when it created as part of
// some internal operation. We are always newer, but if
// the JBC version is > 1 something odd has happened
if (((DefaultDataVersion) dataVersion).getRawVersion() > 1) {
log.warn("Unexpected comparison to " + dataVersion +
" -- we are " + toString());
}
return true;
}
DataVersionAdapter other = (DataVersionAdapter) dataVersion;
if (other.previousVersion == null) {
log.warn("Unexpected optimistic lock check on inserting data");
// work around the "feature" where tree cache is validating the
// inserted node during the next transaction. no idea...
if (this == dataVersion) {
log.trace("skipping lock checks due to same DV instance");
return false;
}
}
if (currentVersion == null) {
// If the workspace node has null as well, OK; if not we've
// been modified in a non-comparable manner, which we have to
// treat as us being newer
return (other.previousVersion != null);
}
// Can't be newer than itself
if ( this == dataVersion ) {
return false;
}
return versionComparator.compare(currentVersion, other.previousVersion) >= 1;
}
public String toString() {
return super.toString() + " [current=" + currentVersion + ", previous=" + previousVersion + ", src="
+ sourceIdentifer + "]";
}
private void writeObject(java.io.ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
// The standard comparator types are not Serializable but are singletons
if (versionComparator instanceof ComparableComparator)
out.writeByte(0);
else if (versionComparator instanceof CalendarComparator)
out.writeByte(1);
else {
out.writeByte(999);
out.writeObject(versionComparator);
}
}
private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
byte comparatorType = in.readByte();
switch (comparatorType) {
case 0:
versionComparator = ComparableComparator.INSTANCE;
break;
case 1:
versionComparator = CalendarComparator.INSTANCE;
break;
default:
versionComparator = (Comparator) in.readObject();
}
}
}