/**
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 Apr 13, 2007
*/
package com.bigdata.rdf.inf;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicLong;
import com.bigdata.rdf.changesets.IChangeLog;
import com.bigdata.rdf.internal.IV;
import com.bigdata.rdf.model.BigdataBNode;
import com.bigdata.rdf.spo.ISPO;
import com.bigdata.rdf.spo.ISPOAssertionBuffer;
import com.bigdata.rdf.spo.JustificationWriter;
import com.bigdata.rdf.spo.SPO;
import com.bigdata.rdf.spo.StatementWriter;
import com.bigdata.rdf.store.AbstractTripleStore;
import com.bigdata.relation.accesspath.IElementFilter;
import com.bigdata.relation.accesspath.AbstractElementBuffer.InsertBuffer;
import com.bigdata.relation.rule.eval.AbstractSolutionBuffer.InsertSolutionBuffer;
import com.bigdata.striterator.ChunkedArrayIterator;
/**
* A buffer for {@link ISPO}s and optional {@link Justification}s that is
* flushed on overflow into a backing {@link AbstractTripleStore}.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*
* @deprecated by {@link InsertBuffer} and {@link InsertSolutionBuffer} and the
* changes to how truth maintenance is handled (by rule rewrites).
*/
public class SPOAssertionBuffer extends AbstractSPOBuffer implements ISPOAssertionBuffer {
/**
* The database on which the lexicon is stored.
*/
final private AbstractTripleStore db;
/**
* The focusStore on which the entailments computed by closure will be
* written. This may be either the database or a temporary focusStore used
* during incremental TM.
*/
final private AbstractTripleStore focusStore;
/**
* The focusStore on which the entailments computed by closure will be
* written. This may be either the database or a temporary focusStore used
* during incremental TM.
*/
public AbstractTripleStore getFocusStore() {
return focusStore;
}
/**
* The array in which the optional {@link Justification}s are stored.
*/
final private Justification[] justifications;
/**
* The #of justifications currently in {@link #justifications}
*/
private int numJustifications;
public int getJustificationCount() {
return numJustifications;
}
/**
* true iff the Truth Maintenance strategy requires that we focusStore
* {@link Justification}s for entailments.
*/
protected final boolean justify;
/**
* Used for change set notification (optional).
*/
protected final IChangeLog changeLog;
/**
* Create a buffer.
*
* @param focusStore
* The focusStore on which the entailments computed by closure
* will be written (required). This is either the database or a
* temporary focusStore used during incremental TM.
* @param db
* The database in which the terms are defined (required).
* @param filter
* Option filter. When present statements matched by the filter
* are NOT retained by the {@link SPOAssertionBuffer} and will
* NOT be added to the <i>focusStore</i>.
* @param capacity
* The maximum {@link SPO}s that the buffer can hold before it
* is {@link #flush()}ed.
* @param justified
* true iff the Truth Maintenance strategy requires that we
* focusStore {@link Justification}s for entailments.
*/
public SPOAssertionBuffer(AbstractTripleStore focusStore,
AbstractTripleStore db, IElementFilter<ISPO> filter, int capacity,
boolean justified) {
this(focusStore, db, filter, capacity, justified,
null/* changeLog */);
}
/**
* Create a buffer.
*
* @param focusStore
* The focusStore on which the entailments computed by closure
* will be written (required). This is either the database or a
* temporary focusStore used during incremental TM.
* @param db
* The database in which the terms are defined (required).
* @param filter
* Option filter. When present statements matched by the filter
* are NOT retained by the {@link SPOAssertionBuffer} and will
* NOT be added to the <i>focusStore</i>.
* @param capacity
* The maximum {@link SPO}s that the buffer can hold before it
* is {@link #flush()}ed.
* @param justified
* true iff the Truth Maintenance strategy requires that we
* focusStore {@link Justification}s for entailments.
* @param changeLog
* optional change log for change notification
*/
public SPOAssertionBuffer(AbstractTripleStore focusStore,
AbstractTripleStore db, IElementFilter<ISPO> filter, int capacity,
boolean justified, final IChangeLog changeLog
) {
super(db, filter, capacity);
if (focusStore == null)
throw new IllegalArgumentException();
if (db == null)
throw new IllegalArgumentException();
this.db = db;
this.focusStore = focusStore;
this.justify = justified;
justifications = justified ? new Justification[capacity] : null;
this.changeLog = changeLog;
}
/**
* Returns true iff there is no more space remaining in the buffer. Under
* those conditions adding another statement to the buffer could cause an
* overflow.
*
* @return True if the buffer might overflow if another statement were
* added.
*/
protected boolean nearCapacity() {
if(super.nearCapacity()) return true;
if (numJustifications + 1 > capacity) {
// would overflow the justification[].
return true;
}
return false;
}
public int flush() {
if (isEmpty()) return 0;
final long n;
if(log.isInfoEnabled()) log.info("numStmts=" + numStmts+", numJustifications="+numJustifications);
final long begin = System.currentTimeMillis();
if (numJustifications == 0) {
if (changeLog == null) {
// batch insert statements into the focusStore.
n = db.addStatements(
focusStore,
true/* copyOnly */,
new ChunkedArrayIterator<ISPO>(numStmts, stmts, null/*keyOrder*/),
null/*filter*/);
} else {
n = com.bigdata.rdf.changesets.StatementWriter.addStatements(
db,
focusStore,
true/* copyOnly */,
null/* filter */,
new ChunkedArrayIterator<ISPO>(numStmts, stmts, null/*keyOrder*/),
changeLog);
}
} else {
/*
* Use a thread pool to write out the statement and the
* justifications concurrently. This dramatically reduces the
* latency when also writing justifications.
*/
final List<Callable<Long>> tasks = new ArrayList<Callable<Long>>(2);
/*
* Note: we reject using the filter before stmts or
* justifications make it into the buffer so we do not need to
* apply the filter again here.
*/
// set as a side-effect.
final AtomicLong nwritten = new AtomicLong();
// task will write SPOs on the statement indices.
tasks.add(new StatementWriter(getTermDatabase(), focusStore,
false/* copyOnly */, new ChunkedArrayIterator<ISPO>(
numStmts, stmts, null/*keyOrder*/), nwritten,
changeLog));
// task will write justifications on the justifications index.
final AtomicLong nwrittenj = new AtomicLong();
tasks.add(new JustificationWriter(focusStore,
new ChunkedArrayIterator<Justification>(numJustifications,
justifications, null/* keyOrder */), nwrittenj));
final List<Future<Long>> futures;
final long elapsed_SPO;
final long elapsed_JST;
try {
futures = focusStore.getIndexManager().getExecutorService().invokeAll( tasks );
elapsed_SPO = futures.get(0).get();
elapsed_JST = futures.get(1).get();
} catch(InterruptedException ex) {
throw new RuntimeException(ex);
} catch(ExecutionException ex) {
throw new RuntimeException(ex);
}
if(log.isInfoEnabled()) log.info("Wrote " + nwritten + " statements in " + elapsed_SPO
+ "ms and " + nwrittenj + " justifications in "
+ elapsed_JST + "ms");
n = nwritten.get();
} // end else
/*
* reset the buffer.
*/
final long elapsed = System.currentTimeMillis() - begin;
if(log.isInfoEnabled()) log.info("Wrote "
+ n
+ " statements"
+ (justify ? " with " + numJustifications + " justifications"
: "") + " in " + elapsed + "ms");
numStmts = numJustifications = 0;
// FIXME Note: being truncated to int, but whole class is deprecated.
return (int) Math.min(Integer.MAX_VALUE, n);
}
/**
* When the buffer is {@link #nearCapacity()} the statements in the buffer
* will be flushed into the backing focusStore.
*
* @see #nearCapacity()
* @see #flush()
*/
public boolean add( final SPO stmt, final Justification justification) {
if (!super.add(stmt)) {
/*
* Note: Do not add focusStore statements (or justifications)
* matched by the filter.
*/
if(DEBUG) {
log.debug("(filtered out)"
+ "\n"
+ (justification == null ? stmt.toString(getTermDatabase())
: justification.toString(getTermDatabase())));
}
return false;
}
/*
* When justification is required the rule MUST supply a justification.
*
* When it is NOT required then the rule SHOULD NOT supply a
* justification.
*/
assert justify ? justification != null : justification == null;
if(justify) {
justifications[numJustifications++] = justification;
if (DEBUG) {
/*
* Note: If [focusStore] is a TempTripleStore then this will NOT be able
* to resolve the terms from the ids (since the lexicon is only in
* the database).
*/
log.debug("\n"
+ (justification == null ? stmt.toString(getTermDatabase())
: justification.toString(getTermDatabase())));
}
}
return true;
}
/**
* @todo also dump the justifications.
*/
public void dump(AbstractTripleStore store) {
System.err.println("numJusts=" + numJustifications);
super.dump(store);
}
}