/*
* 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.server.rmi;
// Java 2 standard packages
import java.net.URI;
import java.rmi.*;
import java.util.*;
// JRDF
import org.jrdf.graph.*;
// Locally written packages
import org.mulgara.jrdf.*;
import org.mulgara.query.*;
import org.mulgara.server.JRDFSession;
/**
* Wrapper around a {@link LocalJRDFSession} to make it look like a
* {@link RemoteJRDFSession}.
*
* @author Andrew Newman
*
* @created 2004-11-02
*
* @version $Revision: 1.14 $
*
* @modified $Date: 2005/01/28 00:30:36 $ by $Author: newmana $
*
* @company <A href="mailto:info@PIsoftware.com">Plugged In Software</A>
*
* @copyright © 2002-2003 <A href="http://www.PIsoftware.com/">Plugged In
* Software Pty Ltd</A>
*
* @licence <a href="{@docRoot}/../../LICENCE">Mozilla Public License v1.1</a>
*/
class JRDFSessionWrapperRemoteJRDFSession extends SessionWrapperRemoteSession
implements RemoteJRDFSession {
/**
* The wrapped {@link JRDFSession}
*/
private final LocalJRDFSession jrdfSession;
/**
* Contains a reference of in memory blank nodes to internal node ids. Reset
* every transaction.
*/
private HashMap<BlankNode,BlankNode> bNodeMap = new HashMap<BlankNode,BlankNode>();
// private HashMap<org.jrdf.graph.mem.BlankNodeImpl,BlankNode> bNodeMap = new HashMap<org.jrdf.graph.mem.BlankNodeImpl,BlankNode>();
//
// Constructor
//
JRDFSessionWrapperRemoteJRDFSession(LocalJRDFSession session) {
super(session);
// Initialize fields
this.jrdfSession = session;
}
public void commit() throws QueryException, RemoteException {
// Clear node map.
bNodeMap.clear();
super.commit();
}
public void rollback() throws QueryException, RemoteException {
// Clean node map.
bNodeMap.clear();
super.rollback();
}
public void setAutoCommit(boolean autoCommit) throws QueryException,
RemoteException {
// Turning autocommit on resets map.
if (autoCommit) {
bNodeMap.clear();
}
super.setAutoCommit(autoCommit);
}
public RemoteAnswer find(URI modelURI, SubjectNode subject,
PredicateNode predicate, ObjectNode object)
throws GraphException, RemoteException {
try {
JRDFGraph graph = new JRDFGraph((JRDFSession) jrdfSession, modelURI);
SubjectNode subjectNode = subject;
PredicateNode predicateNode = predicate;
ObjectNode objectNode = object;
if (subjectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
subjectNode = createBlankNode(
((org.jrdf.graph.mem.BlankNodeImpl) subjectNode),
graph.getElementFactory());
}
if (objectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
objectNode = createBlankNode(
((org.jrdf.graph.mem.BlankNodeImpl) objectNode),
graph.getElementFactory());
}
// Wrap results from regular find in a wrapper to convert blank nodes.
Answer ans = new BlankNodeWrapperAnswer(jrdfSession.find(modelURI,
subjectNode, predicateNode, objectNode), bNodeMap);
try {
if (ans.getRowExpectedCount() <= RemoteAnswer.MARSHALL_SIZE_LIMIT) {
RemoteAnswer serialAnswer = new AnswerWrapperRemoteAnswerSerialised(new
ArrayAnswer(ans));
ans.close();
return serialAnswer;
}
else {
return new AnswerWrapperRemoteAnswer(ans);
}
}
catch (TuplesException e) {
throw new QueryException("Error getting information for answer", e);
}
}
catch (Throwable t) {
throw convertToGraphException(t);
}
}
public boolean contains(URI modelURI, SubjectNode subject,
PredicateNode predicate, ObjectNode object)
throws GraphException, RemoteException {
try {
JRDFGraph graph = new JRDFGraph((JRDFSession) jrdfSession, modelURI);
SubjectNode subjectNode = subject;
PredicateNode predicateNode = predicate;
ObjectNode objectNode = object;
if (subjectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
subjectNode = createBlankNode(
((org.jrdf.graph.mem.BlankNodeImpl) subjectNode),
graph.getElementFactory());
}
if (objectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
objectNode = createBlankNode(
((org.jrdf.graph.mem.BlankNodeImpl) objectNode),
graph.getElementFactory());
}
return jrdfSession.contains(modelURI, subjectNode, predicateNode,
objectNode);
}
catch (Throwable t) {
throw convertToGraphException(t);
}
}
public long getNumberOfTriples(URI graphURI) {
try {
return jrdfSession.getNumberOfTriples(graphURI);
}
catch (Throwable t) {
return -1;
}
}
/**
* Perform a query locally and return an Answer object that can be exported
* over a network.
*
* @param query The query to perform.
* @return A wrapper object that holds an answer, but implements the RemoteAnswer interface.
* This object can be exported across a network.
* @throws QueryException An exception was performed while executing a query.
* @throws RemoteException Should not occur at this end of a connection.
*/
public RemoteAnswer query(Query query) throws QueryException, RemoteException {
// Generate the answer locally
Answer localAnswer = jrdfSession.query(query);
return convertToRemoteAnswer(localAnswer);
}
public boolean query(AskQuery query) throws QueryException, RemoteException {
return jrdfSession.query(query);
}
/**
* Queries the local server and returns a remote reference to an Answer.
*
* @param query The query to perform.
* @return A remote reference to an Answer.
* @throws QueryException The query caused an exception.
* @throws RemoteException Thrown when there is a network error.
*/
public RemoteAnswer query(ConstructQuery query) throws QueryException, RemoteException {
return convertToRemoteAnswer(jrdfSession.query(query));
}
public void insert(URI modelURI, Set<? extends Triple> statements)
throws QueryException, RemoteException {
try {
JRDFGraph graph = new JRDFGraph((JRDFSession) jrdfSession, modelURI);
HashSet<Triple> newStatements = new HashSet<Triple>();
// Iterator through the statements replacing JRDF memory blank nodes with
// server specific blank nodes from the map.
Iterator<? extends Triple> iter = statements.iterator();
while (iter.hasNext()) {
Triple tmpTriple = (Triple) iter.next();
SubjectNode subjectNode = tmpTriple.getSubject();
PredicateNode predicateNode = tmpTriple.getPredicate();
ObjectNode objectNode = tmpTriple.getObject();
// Replace subject blank nodes.
if (subjectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
subjectNode = createBlankNode(
((org.jrdf.graph.mem.BlankNodeImpl) subjectNode),
graph.getElementFactory());
}
// Replace object blank nodes.
if (objectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
objectNode = createBlankNode(
((org.jrdf.graph.mem.BlankNodeImpl) objectNode),
graph.getElementFactory());
}
newStatements.add(new org.mulgara.query.rdf.TripleImpl(subjectNode,
predicateNode, objectNode));
}
super.insert(modelURI, newStatements);
}
catch (GraphException ge) {
throw new QueryException("Failed to insert statements", ge);
}
catch (GraphElementFactoryException gef) {
throw new QueryException("Failed to insert statements", gef);
}
}
public void delete(URI modelURI, Set<? extends Triple> statements) throws QueryException,
RemoteException {
try {
JRDFGraph graph = new JRDFGraph((JRDFSession) jrdfSession, modelURI);
HashSet<Triple> newStatements = new HashSet<Triple>();
// Iterator through the statements replacing JRDF memory blank nodes with
// server specific blank nodes from the map.
Iterator<? extends Triple> iter = statements.iterator();
while (iter.hasNext()) {
Triple tmpTriple = (Triple) iter.next();
SubjectNode subjectNode = tmpTriple.getSubject();
PredicateNode predicateNode = tmpTriple.getPredicate();
ObjectNode objectNode = tmpTriple.getObject();
// Replace subject blank nodes.
if (subjectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
subjectNode = removeBlankNode((org.jrdf.graph.mem.BlankNodeImpl) subjectNode,
graph.getElementFactory());
}
// Replace object blank nodes.
if (objectNode instanceof org.jrdf.graph.mem.BlankNodeImpl) {
objectNode = removeBlankNode((org.jrdf.graph.mem.BlankNodeImpl) objectNode,
graph.getElementFactory());
}
// Create new statemet.
newStatements.add(new org.mulgara.query.rdf.TripleImpl(subjectNode,
predicateNode, objectNode));
}
super.delete(modelURI, newStatements);
}
catch (GraphException ge) {
throw new QueryException("Failed to delete statements", ge);
}
catch (GraphElementFactoryException gef) {
throw new QueryException("Failed to delete statements", gef);
}
}
/**
* Used when adding statements with blank nodes in them. Returns one if
* it already exists in the map or creates a new one (adding it to the map).
*
* @param existingNode the existing memory blank node.
* @param factory the factory to be used to create new resources.
* @throws GraphElementFactoryException if there was an exception creating
* new resources.
* @return the blank node from the map or a new blank node.
*/
private BlankNode createBlankNode(org.jrdf.graph.mem.BlankNodeImpl existingNode,
GraphElementFactory factory) throws GraphElementFactoryException {
if (bNodeMap.containsKey(existingNode)) {
return (BlankNode) bNodeMap.get(existingNode);
} else {
BlankNode bNode = factory.createResource();
bNodeMap.put(existingNode, bNode);
return bNode;
}
}
/**
* Used when removing statements with blank nodes in them. Returns one if
* it already exists in the map or creates a new one (without adding it to
* the map).
*
* @param existingNode the existing memory blank node.
* @param factory the factory to be used to create new resources.
* @throws GraphElementFactoryException if there was an exception creating
* new resources.
* @return the blank node from the map or a new blank node.
*/
private BlankNode removeBlankNode(org.jrdf.graph.mem.BlankNodeImpl existingNode,
GraphElementFactory factory) throws GraphElementFactoryException {
if (bNodeMap.containsKey(existingNode)) {
BlankNode bNode = (BlankNode) bNodeMap.get(existingNode);
return bNode;
}
else {
return factory.createResource();
}
}
/**
* Return t if it is already a QueryException or wrap it as one.
*
* @return t if it is already a QueryException or wrap it as one.
*/
protected GraphException convertToGraphException(Throwable t) {
t = mapThrowable(t);
if (t instanceof GraphException) return (GraphException) t;
return new GraphException(t.toString(), t);
}
private RemoteAnswer convertToRemoteAnswer(Answer ans) throws QueryException, RemoteException {
try {
if (ans.getRowExpectedCount() <= RemoteAnswer.MARSHALL_SIZE_LIMIT) {
RemoteAnswer serialAnswer = new AnswerWrapperRemoteAnswerSerialised(new ArrayAnswer(ans));
ans.close();
return serialAnswer;
} else {
return new AnswerWrapperRemoteAnswer(ans);
}
} catch (TuplesException e) {
throw new QueryException("Unable to resolve answer", e);
}
}
}