/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.rdf.rio;
import org.openrdf.model.Resource;
import org.openrdf.model.Statement;
import org.openrdf.model.Value;
import org.openrdf.rio.RDFHandler;
import org.openrdf.rio.RDFHandlerException;
import com.bigdata.rdf.model.BigdataURI;
/**
* Statement handler for the RIO RDF Parser that writes on a
* {@link StatementBuffer}.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public class PresortRioLoader extends BasicRioLoader implements RDFHandler
{
/**
* Used to buffer RDF {@link Value}s and {@link Statement}s emitted by
* the RDF parser (the value is supplied by the ctor).
*/
final protected IStatementBuffer<?> buffer;
/**
* When true, the <i>buffer</i> will be flushed when the end of the input is
* reached.
*
* @see BLZG-1562 (DataLoader.Options.FLUSH does not defer flush of
* StatementBuffer)
*/
private final boolean flush;
/**
* The value that will be used for the graph/context co-ordinate when
* loading data represented in a triple format into a quad store.
*/
private BigdataURI defaultGraphURI = null ;
/**
* Sets up parser to load RDF.
*
* @param buffer
* The buffer used to collect, sort, and write statements onto
* the database.
*/
public PresortRioLoader(final IStatementBuffer<?> buffer) {
this(buffer, true/* flush */);
}
/**
*
* @param buffer
* The buffer onto which the parsed statements will be written.
* @param flush
* When true, the <i>buffer</i> will be flushed when the end of
* the input is reached.
*
* @see BLZG-1562 (DataLoader.Options.FLUSH does not defer flush of
* StatementBuffer)
*/
public PresortRioLoader(final IStatementBuffer<?> buffer, final boolean flush) {
super(buffer.getDatabase().getValueFactory());
this.buffer = buffer;
this.flush = flush;
}
/**
* {@inheritDoc}
* <p>
* bulk insert the buffered data into the store iff <code>flush:=true</code>
*/
@Override
protected void success() {
if (buffer != null && flush) {
buffer.flush();
}
}
@Override
protected void error(final Exception ex) {
if(buffer != null) {
// discard all buffered data.
buffer.reset();
}
super.error( ex );
}
@Override
public RDFHandler newRDFHandler() {
defaultGraphURI = null != defaultGraph && buffer.getDatabase().isQuads()
? buffer.getDatabase ().getValueFactory ().createURI ( defaultGraph )
: null
;
return this;
}
@Override
public void handleStatement(final Statement stmt) {
if (log.isDebugEnabled()) {
log.debug(stmt);
}
Resource graph = stmt.getContext() ;
if (null == graph && null != defaultGraphURI) {
/*
* Only true when we know we are loading a quad store.
*/
graph = defaultGraphURI;
}
// buffer the write (handles overflow).
buffer.add(stmt.getSubject(), stmt.getPredicate(), stmt.getObject(),
graph);
stmtsAdded++;
if ( stmtsAdded % 100000 == 0 ) {
notifyListeners();
}
}
@Override
public void endRDF() throws RDFHandlerException {
// @todo why not invoke buffer#force()?
}
@Override
public void handleComment(String arg0) throws RDFHandlerException {
}
@Override
public void handleNamespace(String arg0, String arg1) throws RDFHandlerException {
}
@Override
public void startRDF() throws RDFHandlerException {
}
}