/**
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.bop.solutions;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.FutureTask;
import com.bigdata.bop.BOp;
import com.bigdata.bop.BOpContext;
import com.bigdata.bop.ConcurrentHashMapAnnotations;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.IQueryAttributes;
import com.bigdata.bop.IVariable;
import com.bigdata.bop.NV;
import com.bigdata.bop.PipelineOp;
import com.bigdata.bop.engine.BOpStats;
import com.bigdata.bop.join.IDistinctFilter;
import com.bigdata.bop.join.JVMDistinctFilter;
import com.bigdata.bop.join.JVMHashJoinUtility;
import com.bigdata.relation.accesspath.IBlockingBuffer;
import com.bigdata.relation.accesspath.UnsyncLocalOutputBuffer;
import cutthecrap.utils.striterators.ICloseableIterator;
/**
* A pipelined DISTINCT operator based on a hash table.
* <p>
* Note: This implementation is a pipelined operator which inspects each chunk
* of solutions as they arrive and those solutions which are distinct for each
* chunk are passed on. It uses a {@link ConcurrentMap} and is thread-safe. It
* is significantly faster than the single-threaded hash index routines in the
* {@link JVMHashJoinUtility}.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id: DistinctElementFilter.java 3466 2010-08-27 14:28:04Z
* thompsonbry $
*/
public class JVMDistinctBindingSetsOp extends PipelineOp {
// private final static transient Logger log = Logger
// .getLogger(JVMDistinctBindingSetsOp.class);
/**
*
*/
private static final long serialVersionUID = 1L;
public interface Annotations extends PipelineOp.Annotations,
ConcurrentHashMapAnnotations, DistinctAnnotations {
}
/**
* Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
*/
public JVMDistinctBindingSetsOp(final JVMDistinctBindingSetsOp op) {
super(op);
}
/**
* Required shallow copy constructor.
*/
public JVMDistinctBindingSetsOp(final BOp[] args,
final Map<String, Object> annotations) {
super(args, annotations);
switch (getEvaluationContext()) {
case CONTROLLER:
case HASHED:
break;
default:
throw new UnsupportedOperationException(
Annotations.EVALUATION_CONTEXT + "="
+ getEvaluationContext());
}
// shared state is used to share the hash table.
if (!isSharedState()) {
throw new UnsupportedOperationException(Annotations.SHARED_STATE
+ "=" + isSharedState());
}
final IVariable<?>[] vars = (IVariable[]) getProperty(Annotations.VARIABLES);
if (vars == null)
throw new IllegalArgumentException();
}
public JVMDistinctBindingSetsOp(final BOp[] args, NV... annotations) {
this(args, NV.asMap(annotations));
}
/**
* @see Annotations#INITIAL_CAPACITY
*/
public int getInitialCapacity() {
return getProperty(Annotations.INITIAL_CAPACITY,
Annotations.DEFAULT_INITIAL_CAPACITY);
}
/**
* @see Annotations#LOAD_FACTOR
*/
public float getLoadFactor() {
return getProperty(Annotations.LOAD_FACTOR,
Annotations.DEFAULT_LOAD_FACTOR);
}
/**
* @see Annotations#CONCURRENCY_LEVEL
*/
public int getConcurrencyLevel() {
return getProperty(Annotations.CONCURRENCY_LEVEL,
Annotations.DEFAULT_CONCURRENCY_LEVEL);
}
/**
* @see Annotations#VARIABLES
*/
public IVariable<?>[] getVariables() {
return (IVariable<?>[]) getRequiredProperty(Annotations.VARIABLES);
}
public FutureTask<Void> eval(final BOpContext<IBindingSet> context) {
return new FutureTask<Void>(new DistinctTask(this, context));
}
/**
* Task executing on the node.
*/
static private class DistinctTask implements Callable<Void> {
private final BOpContext<IBindingSet> context;
private final IDistinctFilter filter;
private final int chunkCapacity;
DistinctTask(final JVMDistinctBindingSetsOp op,
final BOpContext<IBindingSet> context) {
this.context = context;
this.chunkCapacity = op.getChunkCapacity();
final IVariable<?>[] vars = op.getVariables();
/*
* The map is shared state across invocations of this operator task.
*/
{
final Integer key = op.getId();
final IQueryAttributes attribs = context.getRunningQuery()
.getAttributes();
IDistinctFilter filter = (IDistinctFilter) attribs.get(key);
if (filter == null) {
filter = new JVMDistinctFilter(vars,
op.getInitialCapacity(), op.getLoadFactor(),
op.getConcurrencyLevel());
final IDistinctFilter tmp = (IDistinctFilter) attribs
.putIfAbsent(key, filter);
if (tmp != null)
filter = tmp;
}
this.filter = filter;
}
}
@Override
public Void call() throws Exception {
final BOpStats stats = context.getStats();
final ICloseableIterator<IBindingSet[]> itr = context.getSource();
final IBlockingBuffer<IBindingSet[]> sink = context.getSink();
try {
final UnsyncLocalOutputBuffer<IBindingSet> unsyncBuffer = new UnsyncLocalOutputBuffer<IBindingSet>(
chunkCapacity, sink);
filter.filterSolutions(itr, stats, unsyncBuffer);
unsyncBuffer.flush();
sink.flush();
// done.
return null;
} finally {
if (context.isLastInvocation()) {
filter.release();
}
sink.close();
}
}
}
}