/**
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.internal;
import java.util.LinkedHashSet;
import java.util.Set;
import org.openrdf.model.Literal;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import org.openrdf.model.datatypes.XMLDatatypeUtil;
import org.openrdf.model.impl.URIImpl;
import com.bigdata.rdf.internal.impl.literal.AbstractLiteralIV;
import com.bigdata.rdf.internal.impl.literal.LiteralExtensionIV;
import com.bigdata.rdf.internal.impl.literal.XSDNumericIV;
import com.bigdata.rdf.model.BigdataURI;
import com.bigdata.rdf.model.BigdataValue;
import com.bigdata.rdf.model.BigdataValueFactory;
import com.bigdata.rdf.store.BD;
/**
* This implementation of {@link IExtension} implements inlining for literals
* that represent time in milliseconds since the epoch. The milliseconds are
* encoded as an inline long.
*/
public class EpochExtension<V extends BigdataValue> implements IExtension<V> {
/**
* The datatype URI for the epoch extension.
*/
public transient static final URI EPOCH = new URIImpl(BD.NAMESPACE + "Epoch");
private final BigdataURI epoch;
public EpochExtension(final IDatatypeURIResolver resolver) {
this.epoch = resolver.resolve(EPOCH);
}
public Set<BigdataURI> getDatatypes() {
final Set<BigdataURI> datatypes = new LinkedHashSet<BigdataURI>();
datatypes.add(epoch);
return datatypes;
}
/**
* Attempts to convert the supplied value into an epoch representation.
* Tests for a literal value with the correct datatype that can be converted
* to a positive long integer. Encodes the long in a delegate
* {@link XSDLongIV}, and returns an {@link LiteralExtensionIV} to wrap the native
* type.
*/
public LiteralExtensionIV createIV(final Value value) {
if (value instanceof Literal == false)
throw new IllegalArgumentException();
final Literal lit = (Literal) value;
final URI dt = lit.getDatatype();
if (dt == null || !EPOCH.stringValue().equals(dt.stringValue()))
throw new IllegalArgumentException();
final String s = value.stringValue();
final long l = XMLDatatypeUtil.parseLong(s);
final AbstractLiteralIV delegate = new XSDNumericIV(l);
return new LiteralExtensionIV(delegate, epoch.getIV());
}
/**
* Use the string value of the {@link LiteralExtensionIV} (which defers to the
* string value of the native type) to create a literal with the epoch
* datatype.
*/
public V asValue(final LiteralExtensionIV iv, final BigdataValueFactory vf) {
return (V) vf.createLiteral(iv.getDelegate().stringValue(), epoch);
}
}