/*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* The Original Code is the Kowari Metadata Store.
*
* The Initial Developer of the Original Code is Plugged In Software Pty
* Ltd (http://www.pisoftware.com, mailto:info@pisoftware.com). Portions
* created by Plugged In Software Pty Ltd are Copyright (C) 2001,2002
* Plugged In Software Pty Ltd. All Rights Reserved.
*
* Contributor(s): N/A.
*
* [NOTE: The text of this Exhibit A may differ slightly from the text
* of the notices in the Source Code files of the Original Code. You
* should use the text of this Exhibit A rather than the text found in the
* Original Code Source Code for Your Modifications.]
*
*/
package org.mulgara.resolver;
// Java 2 standard packages
import java.net.URI;
import java.util.Set;
// Third party packages
import org.apache.log4j.Logger;
//JRDF
import org.jrdf.graph.*;
import org.jrdf.graph.mem.*;
// Local packages
import org.mulgara.resolver.jrdf.BlankNodeMap;
import org.mulgara.resolver.jrdf.BlankNodeMapFactory;
import org.mulgara.resolver.spi.*;
import org.mulgara.store.nodepool.NodePool;
import org.mulgara.store.stringpool.SPObject;
import org.mulgara.store.stringpool.StringPool;
import org.mulgara.store.xa.SimpleXAResource;
import org.mulgara.store.xa.SimpleXAResourceException;
import org.mulgara.store.xa.XANodePool;
import org.mulgara.store.xa.XAStringPool;
import org.mulgara.util.UIDGenerator;
/**
* ResolverSession that supports JRDF operations.
*
* @created 2004-10-20
*
* @author <a href="mailto:robert.turner@tucanatech.com">Robert Turner</a>
*
* @version $Revision: 1.8 $
*
* @modified $Date: 2005/01/05 04:58:23 $
*
* @maintenanceAuthor $Author: newmana $
*
* @company <A href="mailto:info@PIsoftware.com">Plugged In Software</A>
*
* @copyright ©2001 <a href="http://www.pisoftware.com/">Plugged In
* Software Pty Ltd</a>
*
* @licence <a href="{@docRoot}/../../LICENCE">Mozilla Public License v1.1</a>
*/
public class JRDFResolverSession extends StringPoolSession {
/** Logger. */
private static final Logger logger =
Logger.getLogger(JRDFResolverSession.class.getName());
/** Used to create BlankNodeMaps */
private BlankNodeMapFactory nodeMapFactory = null;
/** Used to localize/globalize external BlankNodes */
private BlankNodeMap blankNodeMap = null;
/**
* Constructor.
*
* @param databaseURI URI
* @param aliases Set of Strings that are alternative hostnames for this host
* @param persistentStringPool XAStringPool
* @param persistentNodePool XANodePool
* @param temporaryStringPool StringPool
* @param temporaryNodePool NodePool
* @param globalLock Object
*/
JRDFResolverSession(URI databaseURI,
Set aliases,
XAStringPool persistentStringPool,
XANodePool persistentNodePool,
StringPool temporaryStringPool,
NodePool temporaryNodePool,
Object globalLock) {
super(
databaseURI, aliases, persistentStringPool, persistentNodePool,
temporaryStringPool, temporaryNodePool, globalLock
);
this.nodeMapFactory = new BlankNodeMapFactory();
logger.debug("JRDFResolverSession created.");
}
//
// Globalize/Localize methods.
//
/**
* Converts a local node ID to a Global Node.
*
* @param localNode long
* @throws GlobalizeException
* @return Node
*/
public Node globalize(long localNode) throws GlobalizeException
{
Node node = super.globalize(localNode);
return node;
}
/**
* Checks the BlankNodeMap for the localNode. If it is not in the map, a new
* BlankNode is mapped for the id.
*
* @param localNode long
* @param spObject SPObject
* @throws GlobalizeException
* @return BlankNode
*/
protected Node globalizeBlankNode(long localNode, SPObject spObject) throws
GlobalizeException {
BlankNode node = null;
try {
//check map first
node = blankNodeMap.get(localNode);
//was it in there?
if (node == null) {
//create a new mapping
node = newJrdfBlankNode();
blankNodeMap.put( (BlankNodeImpl) node, localNode);
}
} catch (GraphException graphException) {
throw new GlobalizeException(localNode, "Failed to Globalize BlankNode.",
graphException);
}
assert node != null;
return node;
}
/**
* Converts a Global Node to a local node id.
*
* @param node Node
* @param flags int
* @throws LocalizeException
* @return long
*/
protected long localize(Node node, int flags) throws LocalizeException
{
long localNode = super.localize(node, flags);
return localNode;
}
/**
* If the node is an org.jrdf.graph.mem.BlankNodeImpl, the BlankNodeMap is
* checked, otherwise it is handled normally.
*
* @param node BlankNode
* @param flags int
* @throws LocalizeException
* @return long
*/
protected long localizeBlankNode(BlankNode node, int flags) throws
LocalizeException {
//BlankNodeImpl objects can be handled by this class
if (node instanceof BlankNodeImpl) {
return localizeBlankNodeImpl((BlankNodeImpl) node, flags);
} else {
return super.localizeBlankNode(node, flags);
}
}
/**
* Checks the BlankNodeMap before localizing. If the node is not in the map,
* it is added.
*
* @param node BlankNodeImpl
* @param flags int
* @throws LocalizeException
* @return long
*/
protected long localizeBlankNodeImpl(BlankNodeImpl node, int flags) throws
LocalizeException {
long localNode = 0;
try {
//has it been mapped?
localNode = blankNodeMap.get(node);
if (localNode <= 0) {
//get a new node id
localNode = super.localizeBlankNode(node, flags);
//map
blankNodeMap.put(node, localNode);
}
} catch (GraphException graphException) {
throw new LocalizeException(node, "Failed to localize BlankNode.",
graphException);
}
assert localNode > 0;
return localNode;
}
/**
* Creates a new org.jrdf.graph.mem.BlankNodeImpl containing a new
* Globally Unique Identifier.
*
* @throws GraphException
* @return BlankNodeImpl
*/
private BlankNodeImpl newJrdfBlankNode() throws GraphException {
String uid = null;
try {
uid = UIDGenerator.generateUID();
} catch (Exception exception) {
throw new GraphException("Failed to create BlankNode.", exception);
}
//blank node will not have an id
return (BlankNodeImpl)BlankNodeImpl.valueOf(uid + "#0");
}
//
// Transaction code.
//
public void refresh(SimpleXAResource[] resources) throws
SimpleXAResourceException {
super.refresh(resources);
}
/**
* Creates a new BlankNodeMap for the phase.
* @throws SimpleXAResourceException
*/
public void prepare() throws SimpleXAResourceException {
super.prepare();
createBlankNodeMap();
}
/**
* Closes and Invalidates the BlankNodeMap used for the phase.
* @throws SimpleXAResourceException
*/
public void commit() throws SimpleXAResourceException {
super.commit();
deleteBlankNodeMap();
}
/**
* Closes and Invalidates the BlankNodeMap used for the phase.
* @throws SimpleXAResourceException
*/
public void rollback() throws SimpleXAResourceException {
super.rollback();
deleteBlankNodeMap();
}
/**
* Closes and Invalidates the BlankNodeMap used for the phase.
* @throws SimpleXAResourceException
*/
public void release() throws SimpleXAResourceException {
super.release();
deleteBlankNodeMap();
}
/**
* Closes any existing BlankNodeMap and creates a new one.
*
* @throws SimpleXAResourceException
*/
private void createBlankNodeMap() throws SimpleXAResourceException {
//is there already a map?
try {
if (blankNodeMap != null) {
deleteBlankNodeMap();
}
} catch (SimpleXAResourceException resourceException) {
throw new SimpleXAResourceException("Failed to delete existing " +
"BlankNodeMap.", resourceException);
}
//create a new one
try {
blankNodeMap = nodeMapFactory.newBlankNodeMap();
}
catch (GraphException graphException) {
throw new SimpleXAResourceException("Failed to create BlankNodeMap.",
graphException);
}
}
/**
* Closes and invalidates the BlankNodeMap and frees any resources associated
* with it.
*
* @throws SimpleXAResourceException
*/
private void deleteBlankNodeMap() throws SimpleXAResourceException {
try {
blankNodeMap.close();
blankNodeMap = null;
}
catch (GraphException graphException) {
throw new SimpleXAResourceException("Failed to close BlankNodeMap.",
graphException);
}
}
}