/*
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.joinGraph;
import com.bigdata.bop.IPredicate;
import com.bigdata.relation.rule.IRule;
import com.bigdata.relation.rule.IAccessPathExpander;
import com.bigdata.relation.rule.eval.IJoinNexus;
/**
* Useful for testing - will not reorder the join predicates.
*
* @author mike
*/
public class NoReorderEvaluationPlan implements IEvaluationPlan {
protected final IJoinNexus joinNexus;
protected final IRule rule;
protected final long[/*tailIndex*/] rangeCount;
protected final int[] order;
public NoReorderEvaluationPlan(final IJoinNexus joinNexus,
final IRule rule) {
if (joinNexus == null)
throw new IllegalArgumentException();
if (rule == null)
throw new IllegalArgumentException();
this.joinNexus = joinNexus;
this.rule = rule;
final int tailCount = rule.getTailCount();
this.rangeCount = new long[tailCount];
this.order = new int[tailCount];
for (int i = 0; i < tailCount; i++) {
order[i] = i; // -1 is used to detect logic errors.
rangeCount[i] = -1L; // -1L indicates no range count yet.
}
}
public int[] getOrder() {
return order;
}
/**
* <code>true</code> iff the rule was proven to have no solutions.
*
* @todo this is not being computed.
*/
private boolean empty = false;
public boolean isEmpty() {
return empty;
}
public long rangeCount(final int tailIndex) {
if (rangeCount[tailIndex] == -1L) {
final IPredicate predicate = rule.getTail(tailIndex);
final IAccessPathExpander expander = predicate.getAccessPathExpander();
if (expander != null && expander.runFirst()) {
/*
* Note: runFirst() essentially indicates that the cardinality
* of the predicate in the data is to be ignored. Therefore we
* do not request the actual range count and just return -1L as
* a marker indicating that the range count is not available.
*/
return -1L;
}
final long rangeCount = joinNexus.getRangeCountFactory()
.rangeCount(rule.getTail(tailIndex));
this.rangeCount[tailIndex] = rangeCount;
}
return rangeCount[tailIndex];
}
}