/*
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.constraints;
import java.util.Map;
import org.apache.log4j.Logger;
import com.bigdata.bop.BOp;
import com.bigdata.bop.BOpBase;
import com.bigdata.bop.IBindingSet;
import com.bigdata.bop.IConstraint;
import com.bigdata.rdf.internal.NotMaterializedException;
import com.bigdata.util.InnerCause;
/**
* This is useful when a solution can be filtered out before it goes through the
* materialization pipeline. Note that if a solution passes, it will still enter
* the materialization pipeline. It is up to the first step in the pipeline to
* ensure that the solution gets routed around the materialization steps. See
* {@link IsMaterializedBOp}.
*/
public class TryBeforeMaterializationConstraint extends BOpBase implements
IConstraint {
/**
*
*/
private static final long serialVersionUID = -761919593813838105L;
private static final transient Logger log = Logger
.getLogger(TryBeforeMaterializationConstraint.class);
public TryBeforeMaterializationConstraint(final IConstraint x) {
this(new BOp[] { x }, null/*annocations*/);
}
/**
* Required shallow copy constructor.
*/
public TryBeforeMaterializationConstraint(final BOp[] args,
final Map<String, Object> anns) {
super(args, anns);
if (args.length != 1 || args[0] == null)
throw new IllegalArgumentException();
}
/**
* Constructor required for {@link com.bigdata.bop.BOpUtility#deepCopy(FilterNode)}.
*/
public TryBeforeMaterializationConstraint(
final TryBeforeMaterializationConstraint op) {
super(op);
}
/**
* This is useful when a solution can be filtered out before it goes
* through the materialization pipeline. Note that if a solution passes,
* it will still enter the materialization pipeline. It is up to the first
* step in the pipeline to ensure that the solution gets routed around
* the materialization steps. See {@link IsMaterializedBOp}.
*/
@Override
public boolean accept(final IBindingSet bs) {
final IConstraint c = (IConstraint) get(0);
try {
if (log.isDebugEnabled()) {
log.debug("about to attempt evaluation prior to materialization");
}
final boolean accept = c.accept(bs);
if (log.isDebugEnabled()) {
log.debug("successfully evaluated constraint without materialization");
}
return accept;
} catch (Throwable t) {
if (InnerCause.isInnerCause(t, NotMaterializedException.class)) {
if (log.isDebugEnabled()) {
log.debug("could not evaluate constraint without materialization");
}
// let the solution through for now, it will get tested again
// on the other side of the materialization pipeline
return true;
} else
throw new RuntimeException(t);
}
}
}