/**
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
*/
/*
* Created on March 11, 2008
*/
package com.bigdata.rdf.inf;
import java.io.PrintWriter;
import java.io.StringWriter;
import org.apache.log4j.Logger;
import com.bigdata.rdf.internal.IV;
import com.bigdata.rdf.rules.InferenceEngine;
import com.bigdata.rdf.spo.ISPO;
import com.bigdata.rdf.store.AbstractTripleStore;
import com.bigdata.rdf.store.IRawTripleStore;
import com.bigdata.striterator.IChunkedOrderedIterator;
import com.bigdata.striterator.IKeyOrder;
/**
* Provides backward chaining for property collection and reverse property
* collection on owl:sameAs for all access paths.
* <p>
* Note:
*
* @see BackchainOwlSameAsPropertiesSPOIterator
* @see BackchainOwlSameAsPropertiesSPIterator
* @see BackchainOwlSameAsPropertiesPOIterator
* @see BackchainOwlSameAsPropertiesPIterator
* @see InferenceEngine
* @see InferenceEngine.Options
* @author <a href="mailto:mpersonick@users.sourceforge.net">Mike Personick</a>
* @version $Id: BackchainOwlSameAsPropertiesIterator.java,v 1.2 2008/03/20
* 04:05:51 mrpersonick Exp $
*/
public class BackchainOwlSameAsPropertiesIterator implements IChunkedOrderedIterator<ISPO> {
/**
* Enables record of stack traces for callers and verification that the
* iterator is closed.
*/
private static final boolean RECORD_STACK_TRACES = false;
private static final Logger log =
Logger.getLogger(BackchainOwlSameAsPropertiesIterator.class);
private boolean closed = false;
private String stack;
@Override
protected void finalize() throws Throwable {
super.finalize();
if (!closed) {
log
.error("DANGER! Someone needs to close this iterator correctly.\n"
+ (stack != null ? stack : ""));
}
}
private IChunkedOrderedIterator<ISPO> delegate;
/**
* Create an iterator that will visit all statements in the source iterator
* and also backchain any entailments that would have resulted from
* owl:sameAs {2,3}.
*
* @param src
* The source iterator. {@link #nextChunk()} will sort statements
* into the {@link IKeyOrder} reported by this iterator (as long
* as the {@link IKeyOrder} is non-<code>null</code>).
* @param s
* The subject of the triple pattern.
* @param p
* The predicate of the triple pattern.
* @param o
* The object of the triple pattern.
* @param db
* The database from which we will read the distinct subject
* identifiers (iff this is an all unbound triple pattern).
* @param sameAs
* The term identifier that corresponds to owl:sameAs for the
* database.
*/
public BackchainOwlSameAsPropertiesIterator(
IChunkedOrderedIterator<ISPO> src, IV s, IV p, IV o,
AbstractTripleStore db, final IV sameAs) {
if (s != null && o != null) {
this.delegate =
new BackchainOwlSameAsPropertiesSPOIterator(
src, s, p, o, db, sameAs);
} else if (s != null && o == null) {
this.delegate =
new BackchainOwlSameAsPropertiesSPIterator(
src, s, p, db, sameAs);
} else if (s == null && o != null) {
this.delegate =
new BackchainOwlSameAsPropertiesPOIterator(
src, p, o, db, sameAs);
} else if (s == null && o == null) {
this.delegate =
new BackchainOwlSameAsPropertiesPIterator(
src, p, db, sameAs);
} else throw new AssertionError();
if (RECORD_STACK_TRACES) {
StringWriter sw = new StringWriter();
new Exception("Stack trace").printStackTrace(new PrintWriter(sw));
stack = sw.toString();
}
}
public IKeyOrder<ISPO> getKeyOrder() {
return delegate.getKeyOrder();
}
public boolean hasNext() {
return delegate.hasNext();
}
public ISPO next() {
return delegate.next();
}
public ISPO[] nextChunk() {
return delegate.nextChunk();
}
public ISPO[] nextChunk(IKeyOrder<ISPO> keyOrder) {
return delegate.nextChunk(keyOrder);
}
public void close() {
delegate.close();
closed = true;
}
public void remove() {
delegate.remove();
}
}